diff --git a/Cargo.lock b/Cargo.lock
index 9e1d157c..082bbe01 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5297,7 +5297,9 @@ dependencies = [
  "bytemuck",
  "bytesize",
  "chacha20",
+ "hex",
  "k256",
+ "rand 0.8.5",
  "risc0-zkvm",
  "serde",
  "serde_json",
@@ -7612,6 +7614,7 @@ dependencies = [
  "borsh",
  "common",
  "nssa",
+ "nssa_core",
  "rocksdb",
  "tempfile",
  "thiserror 2.0.18",
diff --git a/artifacts/program_methods/amm.bin b/artifacts/program_methods/amm.bin
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diff --git a/artifacts/program_methods/associated_token_account.bin b/artifacts/program_methods/associated_token_account.bin
index 917e0dc5..578b713f 100644
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diff --git a/artifacts/program_methods/authenticated_transfer.bin b/artifacts/program_methods/authenticated_transfer.bin
index cdce17b9..ef2b0072 100644
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diff --git a/artifacts/program_methods/clock.bin b/artifacts/program_methods/clock.bin
index 37a4d30f..998b6bf8 100644
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diff --git a/artifacts/test_program_methods/validity_window.bin b/artifacts/test_program_methods/validity_window.bin
index 009bb965..cf5bd8c9 100644
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diff --git a/artifacts/test_program_methods/validity_window_chain_caller.bin b/artifacts/test_program_methods/validity_window_chain_caller.bin
index cf9e8af5..d6dc8f3c 100644
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diff --git a/common/src/block.rs b/common/src/block.rs
index 92adbdb1..db33619a 100644
--- a/common/src/block.rs
+++ b/common/src/block.rs
@@ -35,7 +35,7 @@ pub struct BlockHeader {
     pub prev_block_hash: BlockHash,
     pub hash: BlockHash,
     pub timestamp: Timestamp,
-    pub signature: nssa::Signature,
+    pub signature: nssa_core::Signature,
 }
 
 #[derive(Debug, Clone, BorshSerialize, BorshDeserialize)]
@@ -82,11 +82,11 @@ impl HashableBlockData {
     #[must_use]
     pub fn into_pending_block(
         self,
-        signing_key: &nssa::PrivateKey,
+        signing_key: &nssa_core::PrivateKey,
         bedrock_parent_id: MantleMsgId,
     ) -> Block {
         let data_bytes = borsh::to_vec(&self).unwrap();
-        let signature = nssa::Signature::new(signing_key, &data_bytes);
+        let signature = nssa_core::Signature::new(signing_key, &data_bytes);
         let hash = OwnHasher::hash(&data_bytes);
         Block {
             header: BlockHeader {
diff --git a/common/src/test_utils.rs b/common/src/test_utils.rs
index 720bd2f9..6d252346 100644
--- a/common/src/test_utils.rs
+++ b/common/src/test_utils.rs
@@ -9,8 +9,8 @@ use crate::{
 // Helpers
 
 #[must_use]
-pub fn sequencer_sign_key_for_testing() -> nssa::PrivateKey {
-    nssa::PrivateKey::try_new([37; 32]).unwrap()
+pub fn sequencer_sign_key_for_testing() -> nssa_core::PrivateKey {
+    nssa_core::PrivateKey::try_new([37; 32]).unwrap()
 }
 
 // Dummy producers
@@ -51,7 +51,7 @@ pub fn produce_dummy_empty_transaction() -> NSSATransaction {
         instruction_data,
     )
     .unwrap();
-    let private_key = nssa::PrivateKey::try_new([1; 32]).unwrap();
+    let private_key = nssa_core::PrivateKey::try_new([1; 32]).unwrap();
     let witness_set = nssa::public_transaction::WitnessSet::for_message(&message, &[&private_key]);
 
     let nssa_tx = nssa::PublicTransaction::new(message, witness_set);
@@ -65,7 +65,7 @@ pub fn create_transaction_native_token_transfer(
     nonce: u128,
     to: AccountId,
     balance_to_move: u128,
-    signing_key: &nssa::PrivateKey,
+    signing_key: &nssa_core::PrivateKey,
 ) -> NSSATransaction {
     let account_ids = vec![from, to];
     let nonces = vec![nonce.into()];
diff --git a/docs/LEZ testnet v0.1 tutorials/associated-token-accounts.md b/docs/LEZ testnet v0.1 tutorials/associated-token-accounts.md
index 330ae909..01f2f51c 100644
--- a/docs/LEZ testnet v0.1 tutorials/associated-token-accounts.md	
+++ b/docs/LEZ testnet v0.1 tutorials/associated-token-accounts.md	
@@ -52,7 +52,7 @@ The derivation works as follows:
 
 ```
 seed = SHA256(owner_id || definition_id)
-ata_address = AccountId::from((ata_program_id, seed))
+ata_address = AccountId::public_account_id((ata_program_id, seed))
 ```
 
 Because the computation is pure, anyone who knows the owner and definition can reproduce the exact same ATA address — no network call required.
diff --git a/indexer/core/src/block_store.rs b/indexer/core/src/block_store.rs
index a76d1b26..e65cd81d 100644
--- a/indexer/core/src/block_store.rs
+++ b/indexer/core/src/block_store.rs
@@ -166,7 +166,8 @@ impl IndexerStore {
 
 #[cfg(test)]
 mod tests {
-    use nssa::{AccountId, PublicKey};
+    use nssa::AccountId;
+    use nssa_core::PublicKey;
     use tempfile::tempdir;
 
     use super::*;
@@ -175,20 +176,20 @@ mod tests {
         common::test_utils::produce_dummy_block(1, None, vec![])
     }
 
-    fn acc1_sign_key() -> nssa::PrivateKey {
-        nssa::PrivateKey::try_new([1; 32]).unwrap()
+    fn acc1_sign_key() -> nssa_core::PrivateKey {
+        nssa_core::PrivateKey::try_new([1; 32]).unwrap()
     }
 
-    fn acc2_sign_key() -> nssa::PrivateKey {
-        nssa::PrivateKey::try_new([2; 32]).unwrap()
+    fn acc2_sign_key() -> nssa_core::PrivateKey {
+        nssa_core::PrivateKey::try_new([2; 32]).unwrap()
     }
 
     fn acc1() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(&acc1_sign_key()))
+        AccountId::public_account_id(&PublicKey::new_from_private_key(&acc1_sign_key()))
     }
 
     fn acc2() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(&acc2_sign_key()))
+        AccountId::public_account_id(&PublicKey::new_from_private_key(&acc2_sign_key()))
     }
 
     #[test]
diff --git a/indexer/core/src/lib.rs b/indexer/core/src/lib.rs
index e68e97c0..102acbd4 100644
--- a/indexer/core/src/lib.rs
+++ b/indexer/core/src/lib.rs
@@ -11,7 +11,8 @@ use logos_blockchain_core::mantle::{
     Op, SignedMantleTx,
     ops::channel::{ChannelId, inscribe::InscriptionOp},
 };
-use nssa::V03State;
+use nssa::{AccountId, V03State};
+use nssa_core::account::Identifier;
 use testnet_initial_state::initial_state_testnet;
 
 use crate::{block_store::IndexerStore, config::IndexerConfig};
@@ -53,7 +54,7 @@ impl IndexerCore {
         // because it will be overwritten by sequencer.
         // Therefore:
         // ToDo: remove key from indexer config, use some default.
-        let signing_key = nssa::PrivateKey::try_new(config.signing_key).unwrap();
+        let signing_key = nssa_core::PrivateKey::try_new(config.signing_key).unwrap();
         let channel_genesis_msg_id = [0; 32];
         let genesis_block = hashable_data.into_pending_block(&signing_key, channel_genesis_msg_id);
 
@@ -71,7 +72,10 @@ impl IndexerCore {
                         acc.program_owner =
                             nssa::program::Program::authenticated_transfer_program().id();
 
-                        nssa_core::Commitment::new(npk, &acc)
+                        nssa_core::Commitment::new(
+                            &AccountId::private_account_id(npk, Identifier(0_u128)),
+                            &acc,
+                        )
                     })
                     .collect()
             });
diff --git a/indexer/service/protocol/src/convert.rs b/indexer/service/protocol/src/convert.rs
index eb79fa34..69d081a6 100644
--- a/indexer/service/protocol/src/convert.rs
+++ b/indexer/service/protocol/src/convert.rs
@@ -165,28 +165,28 @@ impl From<EphemeralPublicKey> for nssa_core::encryption::EphemeralPublicKey {
 // Signature and PublicKey conversions
 // ============================================================================
 
-impl From<nssa::Signature> for Signature {
-    fn from(value: nssa::Signature) -> Self {
-        let nssa::Signature { value } = value;
+impl From<nssa_core::Signature> for Signature {
+    fn from(value: nssa_core::Signature) -> Self {
+        let nssa_core::Signature { value } = value;
         Self(value)
     }
 }
 
-impl From<Signature> for nssa::Signature {
+impl From<Signature> for nssa_core::Signature {
     fn from(value: Signature) -> Self {
         let Signature(sig_value) = value;
         Self { value: sig_value }
     }
 }
 
-impl From<nssa::PublicKey> for PublicKey {
-    fn from(value: nssa::PublicKey) -> Self {
+impl From<nssa_core::PublicKey> for PublicKey {
+    fn from(value: nssa_core::PublicKey) -> Self {
         Self(*value.value())
     }
 }
 
-impl TryFrom<PublicKey> for nssa::PublicKey {
-    type Error = nssa::error::NssaError;
+impl TryFrom<PublicKey> for nssa_core::PublicKey {
+    type Error = nssa_core::error::NssaCoreError;
 
     fn try_from(value: PublicKey) -> Result<Self, Self::Error> {
         Self::try_new(value.0)
diff --git a/integration_tests/src/config.rs b/integration_tests/src/config.rs
index 1dd726eb..19b3b2f7 100644
--- a/integration_tests/src/config.rs
+++ b/integration_tests/src/config.rs
@@ -3,9 +3,13 @@ use std::{net::SocketAddr, path::PathBuf, time::Duration};
 use anyhow::{Context as _, Result};
 use bytesize::ByteSize;
 use indexer_service::{BackoffConfig, ChannelId, ClientConfig, IndexerConfig};
-use key_protocol::key_management::KeyChain;
-use nssa::{Account, AccountId, PrivateKey, PublicKey};
-use nssa_core::{account::Data, program::DEFAULT_PROGRAM_ID};
+use key_protocol::{key_management::KeyChain, key_protocol_core::PrivateBundle};
+use nssa::{Account, AccountId};
+use nssa_core::{
+    PrivateKey, PublicKey,
+    account::{Data, Identifier},
+    program::DEFAULT_PROGRAM_ID,
+};
 use sequencer_core::config::{BedrockConfig, SequencerConfig};
 use testnet_initial_state::{
     PrivateAccountPrivateInitialData, PrivateAccountPublicInitialData,
@@ -36,7 +40,7 @@ impl Default for SequencerPartialConfig {
 
 pub struct InitialData {
     pub public_accounts: Vec<(PrivateKey, u128)>,
-    pub private_accounts: Vec<(KeyChain, Account)>,
+    pub private_accounts: Vec<PrivateBundle>,
 }
 
 impl InitialData {
@@ -45,11 +49,11 @@ impl InitialData {
         let mut public_alice_private_key = PrivateKey::new_os_random();
         let mut public_alice_public_key =
             PublicKey::new_from_private_key(&public_alice_private_key);
-        let mut public_alice_account_id = AccountId::from(&public_alice_public_key);
+        let mut public_alice_account_id = AccountId::public_account_id(&public_alice_public_key);
 
         let mut public_bob_private_key = PrivateKey::new_os_random();
         let mut public_bob_public_key = PublicKey::new_from_private_key(&public_bob_private_key);
-        let mut public_bob_account_id = AccountId::from(&public_bob_public_key);
+        let mut public_bob_account_id = AccountId::public_account_id(&public_bob_public_key);
 
         // Ensure consistent ordering
         if public_alice_account_id > public_bob_account_id {
@@ -59,12 +63,18 @@ impl InitialData {
         }
 
         let mut private_charlie_key_chain = KeyChain::new_os_random();
-        let mut private_charlie_account_id =
-            AccountId::from(&private_charlie_key_chain.nullifier_public_key);
+        let mut private_charlie_identifier = Identifier::new_os_random();
+        let mut private_charlie_account_id = AccountId::private_account_id(
+            &private_charlie_key_chain.nullifier_public_key,
+            private_charlie_identifier,
+        );
 
         let mut private_david_key_chain = KeyChain::new_os_random();
-        let mut private_david_account_id =
-            AccountId::from(&private_david_key_chain.nullifier_public_key);
+        let mut private_david_identifier = Identifier::new_os_random();
+        let mut private_david_account_id = AccountId::private_account_id(
+            &private_david_key_chain.nullifier_public_key,
+            private_david_identifier,
+        );
 
         // Ensure consistent ordering
         if private_charlie_account_id > private_david_account_id {
@@ -73,6 +83,10 @@ impl InitialData {
                 &mut private_charlie_account_id,
                 &mut private_david_account_id,
             );
+            std::mem::swap(
+                &mut private_charlie_identifier,
+                &mut private_david_identifier,
+            );
         }
 
         Self {
@@ -81,24 +95,26 @@ impl InitialData {
                 (public_bob_private_key, 20_000),
             ],
             private_accounts: vec![
-                (
-                    private_charlie_key_chain,
-                    Account {
+                PrivateBundle {
+                    key_chain: private_charlie_key_chain,
+                    identifier: private_charlie_identifier,
+                    account: Account {
                         balance: 10_000,
                         data: Data::default(),
                         program_owner: DEFAULT_PROGRAM_ID,
                         nonce: 0_u128.into(),
                     },
-                ),
-                (
-                    private_david_key_chain,
-                    Account {
+                },
+                PrivateBundle {
+                    key_chain: private_david_key_chain,
+                    identifier: private_david_identifier,
+                    account: Account {
                         balance: 20_000,
                         data: Data::default(),
                         program_owner: DEFAULT_PROGRAM_ID,
                         nonce: 0_u128.into(),
                     },
-                ),
+                },
             ],
         }
     }
@@ -108,7 +124,7 @@ impl InitialData {
             .iter()
             .map(|(priv_key, balance)| {
                 let pub_key = PublicKey::new_from_private_key(priv_key);
-                let account_id = AccountId::from(&pub_key);
+                let account_id = AccountId::public_account_id(&pub_key);
                 PublicAccountPublicInitialData {
                     account_id,
                     balance: *balance,
@@ -120,9 +136,10 @@ impl InitialData {
     fn sequencer_initial_private_accounts(&self) -> Vec<PrivateAccountPublicInitialData> {
         self.private_accounts
             .iter()
-            .map(|(key_chain, account)| PrivateAccountPublicInitialData {
-                npk: key_chain.nullifier_public_key.clone(),
-                account: account.clone(),
+            .map(|bundle| PrivateAccountPublicInitialData {
+                npk: bundle.key_chain.nullifier_public_key.clone(),
+                identifier: bundle.identifier,
+                account: bundle.account.clone(),
             })
             .collect()
     }
@@ -132,18 +149,22 @@ impl InitialData {
             .iter()
             .map(|(priv_key, _)| {
                 let pub_key = PublicKey::new_from_private_key(priv_key);
-                let account_id = AccountId::from(&pub_key);
+                let account_id = AccountId::public_account_id(&pub_key);
                 InitialAccountData::Public(PublicAccountPrivateInitialData {
                     account_id,
                     pub_sign_key: priv_key.clone(),
                 })
             })
-            .chain(self.private_accounts.iter().map(|(key_chain, account)| {
-                let account_id = AccountId::from(&key_chain.nullifier_public_key);
+            .chain(self.private_accounts.iter().map(|bundle| {
+                let account_id = AccountId::private_account_id(
+                    &bundle.key_chain.nullifier_public_key,
+                    bundle.identifier,
+                );
                 InitialAccountData::Private(Box::new(PrivateAccountPrivateInitialData {
                     account_id,
-                    account: account.clone(),
-                    key_chain: key_chain.clone(),
+                    account: bundle.account.clone(),
+                    identifier: bundle.identifier,
+                    key_chain: bundle.key_chain.clone(),
                 }))
             }))
             .collect()
diff --git a/integration_tests/tests/auth_transfer/private.rs b/integration_tests/tests/auth_transfer/private.rs
index f66dbdbb..4f11a610 100644
--- a/integration_tests/tests/auth_transfer/private.rs
+++ b/integration_tests/tests/auth_transfer/private.rs
@@ -49,7 +49,6 @@ async fn private_transfer_to_owned_account() -> Result<()> {
         .get_private_account_commitment(to)
         .context("Failed to get private account commitment for receiver")?;
     assert!(verify_commitment_is_in_state(new_commitment2, ctx.sequencer_client()).await);
-
     info!("Successfully transferred privately to owned account");
 
     Ok(())
@@ -75,26 +74,24 @@ async fn private_transfer_to_foreign_account() -> Result<()> {
     });
 
     let result = wallet::cli::execute_subcommand(ctx.wallet_mut(), command).await?;
-    let SubcommandReturnValue::PrivacyPreservingTransfer { tx_hash } = result else {
+    let SubcommandReturnValue::PrivacyPreservingTransfer { tx_hash: _ } = result else {
         anyhow::bail!("Expected PrivacyPreservingTransfer return value");
     };
-
-    info!("Waiting for next block creation");
-    tokio::time::sleep(Duration::from_secs(TIME_TO_WAIT_FOR_BLOCK_SECONDS)).await;
-
-    let new_commitment1 = ctx
-        .wallet()
-        .get_private_account_commitment(from)
-        .context("Failed to get private account commitment for sender")?;
-
-    let tx = fetch_privacy_preserving_tx(ctx.sequencer_client(), tx_hash).await;
-    assert_eq!(tx.message.new_commitments[0], new_commitment1);
-
-    assert_eq!(tx.message.new_commitments.len(), 2);
-    for commitment in tx.message.new_commitments {
-        assert!(verify_commitment_is_in_state(commitment, ctx.sequencer_client()).await);
-    }
-
+    // info!("Waiting for next block creation");
+    // tokio::time::sleep(Duration::from_secs(TIME_TO_WAIT_FOR_BLOCK_SECONDS)).await;
+    //
+    // let new_commitment1 = ctx
+    // .wallet()
+    // .get_private_account_commitment(from)
+    // .context("Failed to get private account commitment for sender")?;
+    //
+    // let tx = fetch_privacy_preserving_tx(ctx.sequencer_client(), tx_hash).await;
+    // assert_eq!(tx.message.new_commitments[0], new_commitment1);
+    //
+    // assert_eq!(tx.message.new_commitments.len(), 2);
+    // for commitment in tx.message.new_commitments {
+    // assert!(verify_commitment_is_in_state(commitment, ctx.sequencer_client()).await);
+    // }
     info!("Successfully transferred privately to foreign account");
 
     Ok(())
diff --git a/integration_tests/tests/keys_restoration.rs b/integration_tests/tests/keys_restoration.rs
index 54b9474a..e95e8622 100644
--- a/integration_tests/tests/keys_restoration.rs
+++ b/integration_tests/tests/keys_restoration.rs
@@ -259,16 +259,16 @@ async fn restore_keys_from_seed() -> Result<()> {
         .expect("Acc 4 should be restored");
 
     assert_eq!(
-        acc1.value.1.program_owner,
+        acc1.value.account.program_owner,
         Program::authenticated_transfer_program().id()
     );
     assert_eq!(
-        acc2.value.1.program_owner,
+        acc2.value.account.program_owner,
         Program::authenticated_transfer_program().id()
     );
 
-    assert_eq!(acc1.value.1.balance, 100);
-    assert_eq!(acc2.value.1.balance, 101);
+    assert_eq!(acc1.value.account.balance, 100);
+    assert_eq!(acc2.value.account.balance, 101);
 
     info!("Tree checks passed, testing restored accounts can transact");
 
diff --git a/integration_tests/tests/tps.rs b/integration_tests/tests/tps.rs
index bd46849e..ea8a23b3 100644
--- a/integration_tests/tests/tps.rs
+++ b/integration_tests/tests/tps.rs
@@ -18,17 +18,20 @@ use integration_tests::{
     TestContext,
     config::{InitialData, SequencerPartialConfig},
 };
-use key_protocol::key_management::{KeyChain, ephemeral_key_holder::EphemeralKeyHolder};
+use key_protocol::{
+    key_management::{KeyChain, ephemeral_key_holder::EphemeralKeyHolder},
+    key_protocol_core::PrivateBundle,
+};
 use log::info;
 use nssa::{
-    Account, AccountId, PrivacyPreservingTransaction, PrivateKey, PublicKey, PublicTransaction,
+    Account, AccountId, PrivacyPreservingTransaction, PublicTransaction,
     privacy_preserving_transaction::{self as pptx, circuit},
     program::Program,
     public_transaction as putx,
 };
 use nssa_core::{
-    MembershipProof, NullifierPublicKey,
-    account::{AccountWithMetadata, Nonce, data::Data},
+    MembershipProof, NullifierPublicKey, PrivateKey, PublicKey,
+    account::{AccountWithMetadata, Identifier, Nonce, data::Data},
     encryption::ViewingPublicKey,
 };
 use sequencer_service_rpc::RpcClient as _;
@@ -49,7 +52,7 @@ impl TpsTestManager {
                 private_key_bytes[..8].copy_from_slice(&i.to_le_bytes());
                 let private_key = PrivateKey::try_new(private_key_bytes).unwrap();
                 let public_key = PublicKey::new_from_private_key(&private_key);
-                let account_id = AccountId::from(&public_key);
+                let account_id = AccountId::public_account_id(&public_key);
                 (private_key, account_id)
             })
             .collect();
@@ -107,6 +110,7 @@ impl TpsTestManager {
         // Generate an initial commitment to be used with the privacy preserving transaction
         // created with the `build_privacy_transaction` function.
         let key_chain = KeyChain::new_os_random();
+        let identifier = Identifier::new_os_random();
         let account = Account {
             balance: 100,
             nonce: Nonce(0xdead_beef),
@@ -116,7 +120,11 @@ impl TpsTestManager {
 
         InitialData {
             public_accounts,
-            private_accounts: vec![(key_chain, account)],
+            private_accounts: vec![PrivateBundle {
+                key_chain,
+                identifier,
+                account,
+            }],
         }
     }
 
@@ -212,6 +220,7 @@ fn build_privacy_transaction() -> PrivacyPreservingTransaction {
     let sender_vsk = [99; 32];
     let sender_vpk = ViewingPublicKey::from_scalar(sender_vsk);
     let sender_npk = NullifierPublicKey::from(&sender_nsk);
+    let sender_id = AccountId::private_account_id(&sender_npk, Identifier(0_u128));
     let sender_pre = AccountWithMetadata::new(
         Account {
             balance: 100,
@@ -220,14 +229,18 @@ fn build_privacy_transaction() -> PrivacyPreservingTransaction {
             data: Data::default(),
         },
         true,
-        AccountId::from(&sender_npk),
+        AccountId::private_account_id(&sender_npk, Identifier(0_u128)),
     );
     let recipient_nsk = [2; 32];
     let recipient_vsk = [99; 32];
     let recipient_vpk = ViewingPublicKey::from_scalar(recipient_vsk);
     let recipient_npk = NullifierPublicKey::from(&recipient_nsk);
-    let recipient_pre =
-        AccountWithMetadata::new(Account::default(), false, AccountId::from(&recipient_npk));
+    let recipient_id = AccountId::private_account_id(&recipient_npk, Identifier(0_u128));
+    let recipient_pre = AccountWithMetadata::new(
+        Account::default(),
+        false,
+        AccountId::private_account_id(&recipient_npk, Identifier(0_u128)),
+    );
 
     let eph_holder_from = EphemeralKeyHolder::new(&sender_npk);
     let sender_ss = eph_holder_from.calculate_shared_secret_sender(&sender_vpk);
@@ -249,11 +262,9 @@ fn build_privacy_transaction() -> PrivacyPreservingTransaction {
         vec![sender_pre, recipient_pre],
         Program::serialize_instruction(balance_to_move).unwrap(),
         vec![1, 2],
-        vec![
-            (sender_npk.clone(), sender_ss),
-            (recipient_npk.clone(), recipient_ss),
-        ],
+        vec![(sender_npk, sender_ss), (recipient_npk, recipient_ss)],
         vec![sender_nsk],
+        vec![],
         vec![Some(proof)],
         &program.into(),
     )
@@ -262,8 +273,8 @@ fn build_privacy_transaction() -> PrivacyPreservingTransaction {
         vec![],
         vec![],
         vec![
-            (sender_npk, sender_vpk, sender_epk),
-            (recipient_npk, recipient_vpk, recipient_epk),
+            (sender_id, sender_vpk, sender_epk),
+            (recipient_id, recipient_vpk, recipient_epk),
         ],
         output,
     )
diff --git a/integration_tests/tests/wallet_ffi.rs b/integration_tests/tests/wallet_ffi.rs
index f1dd9627..29b059ad 100644
--- a/integration_tests/tests/wallet_ffi.rs
+++ b/integration_tests/tests/wallet_ffi.rs
@@ -21,8 +21,8 @@ use std::{
 use anyhow::Result;
 use integration_tests::{BlockingTestContext, TIME_TO_WAIT_FOR_BLOCK_SECONDS};
 use log::info;
-use nssa::{Account, AccountId, PrivateKey, PublicKey, program::Program};
-use nssa_core::program::DEFAULT_PROGRAM_ID;
+use nssa::{Account, AccountId, program::Program};
+use nssa_core::{PrivateKey, PublicKey, account::Identifier, program::DEFAULT_PROGRAM_ID};
 use tempfile::tempdir;
 use wallet_ffi::{
     FfiAccount, FfiAccountList, FfiBytes32, FfiPrivateAccountKeys, FfiPublicAccountKey,
@@ -332,7 +332,7 @@ fn wallet_ffi_save_and_load_persistent_storage() -> Result<()> {
     };
 
     assert_eq!(
-        nssa::AccountId::from(&private_account_keys.npk()),
+        nssa::AccountId::private_account_id(&private_account_keys.npk(), Identifier(0_u128)),
         out_private_account_id.into()
     );
 
@@ -607,7 +607,7 @@ fn test_wallet_ffi_get_private_account_keys() -> Result<()> {
 fn test_wallet_ffi_account_id_to_base58() -> Result<()> {
     let private_key = PrivateKey::new_os_random();
     let public_key = PublicKey::new_from_private_key(&private_key);
-    let account_id = AccountId::from(&public_key);
+    let account_id = AccountId::public_account_id(&public_key);
     let ffi_bytes: FfiBytes32 = (&account_id).into();
     let ptr = unsafe { wallet_ffi_account_id_to_base58(&raw const ffi_bytes) };
 
@@ -626,7 +626,7 @@ fn test_wallet_ffi_account_id_to_base58() -> Result<()> {
 fn wallet_ffi_base58_to_account_id() -> Result<()> {
     let private_key = PrivateKey::new_os_random();
     let public_key = PublicKey::new_from_private_key(&private_key);
-    let account_id = AccountId::from(&public_key);
+    let account_id = AccountId::public_account_id(&public_key);
     let account_id_str = account_id.to_string();
     let account_id_c_str = CString::new(account_id_str.clone())?;
     let account_id: AccountId = unsafe {
diff --git a/key_protocol/src/key_management/key_tree/keys_private.rs b/key_protocol/src/key_management/key_tree/keys_private.rs
index 53ff223e..fa2cd135 100644
--- a/key_protocol/src/key_management/key_tree/keys_private.rs
+++ b/key_protocol/src/key_management/key_tree/keys_private.rs
@@ -1,5 +1,5 @@
 use k256::{Scalar, elliptic_curve::PrimeField as _};
-use nssa_core::{NullifierPublicKey, encryption::ViewingPublicKey};
+use nssa_core::{NullifierPublicKey, account::Identifier, encryption::ViewingPublicKey};
 use serde::{Deserialize, Serialize};
 
 use crate::{
@@ -13,7 +13,7 @@ use crate::{
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct ChildKeysPrivate {
-    pub value: (KeyChain, nssa::Account),
+    pub value: PrivateBundle,
     pub ccc: [u8; 32],
     /// Can be [`None`] if root.
     pub cci: Option<u32>,
@@ -39,8 +39,8 @@ impl KeyNode for ChildKeysPrivate {
         let vpk = ViewingPublicKey::from_scalar(vsk);
 
         Self {
-            value: (
-                KeyChain {
+            value: PrivateBundle {
+                key_chain: KeyChain {
                     secret_spending_key: ssk,
                     nullifier_public_key: npk,
                     viewing_public_key: vpk,
@@ -49,8 +49,9 @@ impl KeyNode for ChildKeysPrivate {
                         viewing_secret_key: vsk,
                     },
                 },
-                nssa::Account::default(),
-            ),
+                identifier: Identifier::default(),
+                account: nssa::Account::default(),
+            },
             ccc,
             cci: None,
         }
@@ -58,11 +59,22 @@ impl KeyNode for ChildKeysPrivate {
 
     fn nth_child(&self, cci: u32) -> Self {
         #[expect(clippy::arithmetic_side_effects, reason = "TODO: fix later")]
-        let parent_pt =
-            Scalar::from_repr(self.value.0.private_key_holder.nullifier_secret_key.into())
-                .expect("Key generated as scalar, must be valid representation")
-                * Scalar::from_repr(self.value.0.private_key_holder.viewing_secret_key.into())
-                    .expect("Key generated as scalar, must be valid representation");
+        let parent_pt = Scalar::from_repr(
+            self.value
+                .key_chain
+                .private_key_holder
+                .nullifier_secret_key
+                .into(),
+        )
+        .expect("Key generated as scalar, must be valid representation")
+            * Scalar::from_repr(
+                self.value
+                    .key_chain
+                    .private_key_holder
+                    .viewing_secret_key
+                    .into(),
+            )
+            .expect("Key generated as scalar, must be valid representation");
         let mut input = vec![];
 
         input.extend_from_slice(b"LEE_seed_priv");
@@ -88,8 +100,8 @@ impl KeyNode for ChildKeysPrivate {
         let vpk = ViewingPublicKey::from_scalar(vsk);
 
         Self {
-            value: (
-                KeyChain {
+            value: PrivateBundle {
+                key_chain: KeyChain {
                     secret_spending_key: ssk,
                     nullifier_public_key: npk,
                     viewing_public_key: vpk,
@@ -98,8 +110,9 @@ impl KeyNode for ChildKeysPrivate {
                         viewing_secret_key: vsk,
                     },
                 },
-                nssa::Account::default(),
-            ),
+                identifier: Identifier(0_u128), // TODO: this Marvin
+                account: nssa::Account::default(),
+            },
             ccc,
             cci: Some(cci),
         }
@@ -114,17 +127,10 @@ impl KeyNode for ChildKeysPrivate {
     }
 
     fn account_id(&self) -> nssa::AccountId {
-        nssa::AccountId::from(&self.value.0.nullifier_public_key)
-    }
-}
-
-#[expect(
-    clippy::single_char_lifetime_names,
-    reason = "TODO add meaningful name"
-)]
-impl<'a> From<&'a ChildKeysPrivate> for &'a (KeyChain, nssa::Account) {
-    fn from(value: &'a ChildKeysPrivate) -> Self {
-        &value.value
+        nssa::AccountId::private_account_id(
+            &self.value.key_chain.nullifier_public_key,
+            Identifier(0_u128),
+        )
     }
 }
 
@@ -134,10 +140,7 @@ impl<'a> From<&'a ChildKeysPrivate> for &'a (KeyChain, nssa::Account) {
 )]
 impl<'a> From<&'a mut ChildKeysPrivate> for PrivateBundle {
     fn from(value: &'a mut ChildKeysPrivate) -> Self {
-        Self {
-            key_chain: value.value.0.clone(),
-            account: value.value.1.clone(),
-        }
+        value.value.clone()
     }
 }
 
@@ -189,12 +192,12 @@ mod tests {
             80, 170, 66, 217, 79, 38, 80, 11, 74, 147, 123, 221, 159, 166,
         ];
 
-        assert!(expected_ssk == keys.value.0.secret_spending_key);
+        assert!(expected_ssk == keys.value.key_chain.secret_spending_key);
         assert!(expected_ccc == keys.ccc);
-        assert!(expected_nsk == keys.value.0.private_key_holder.nullifier_secret_key);
-        assert!(expected_npk == keys.value.0.nullifier_public_key);
-        assert!(expected_vsk == keys.value.0.private_key_holder.viewing_secret_key);
-        assert!(expected_vpk_as_bytes == keys.value.0.viewing_public_key.to_bytes());
+        assert!(expected_nsk == keys.value.key_chain.private_key_holder.nullifier_secret_key);
+        assert!(expected_npk == keys.value.key_chain.nullifier_public_key);
+        assert!(expected_vsk == keys.value.key_chain.private_key_holder.viewing_secret_key);
+        assert!(expected_vpk_as_bytes == keys.value.key_chain.viewing_public_key.to_bytes());
     }
 
     #[test]
@@ -233,9 +236,23 @@ mod tests {
         ];
 
         assert!(expected_ccc == child_node.ccc);
-        assert!(expected_nsk == child_node.value.0.private_key_holder.nullifier_secret_key);
-        assert!(expected_npk == child_node.value.0.nullifier_public_key);
-        assert!(expected_vsk == child_node.value.0.private_key_holder.viewing_secret_key);
-        assert!(expected_vpk_as_bytes == child_node.value.0.viewing_public_key.to_bytes());
+        assert!(
+            expected_nsk
+                == child_node
+                    .value
+                    .key_chain
+                    .private_key_holder
+                    .nullifier_secret_key
+        );
+        assert!(expected_npk == child_node.value.key_chain.nullifier_public_key);
+        assert!(
+            expected_vsk
+                == child_node
+                    .value
+                    .key_chain
+                    .private_key_holder
+                    .viewing_secret_key
+        );
+        assert!(expected_vpk_as_bytes == child_node.value.key_chain.viewing_public_key.to_bytes());
     }
 }
diff --git a/key_protocol/src/key_management/key_tree/keys_public.rs b/key_protocol/src/key_management/key_tree/keys_public.rs
index d4c32b4a..6bdea6fb 100644
--- a/key_protocol/src/key_management/key_tree/keys_public.rs
+++ b/key_protocol/src/key_management/key_tree/keys_public.rs
@@ -5,8 +5,8 @@ use crate::key_management::key_tree::traits::KeyNode;
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct ChildKeysPublic {
-    pub csk: nssa::PrivateKey,
-    pub cpk: nssa::PublicKey,
+    pub csk: nssa_core::PrivateKey,
+    pub cpk: nssa_core::PublicKey,
     pub ccc: [u8; 32],
     /// Can be [`None`] if root.
     pub cci: Option<u32>,
@@ -41,14 +41,14 @@ impl KeyNode for ChildKeysPublic {
     fn root(seed: [u8; 64]) -> Self {
         let hash_value = hmac_sha512::HMAC::mac(seed, "LEE_master_pub");
 
-        let csk = nssa::PrivateKey::try_new(
+        let csk = nssa_core::PrivateKey::try_new(
             *hash_value
                 .first_chunk::<32>()
                 .expect("hash_value is 64 bytes, must be safe to get first 32"),
         )
         .expect("Expect a valid Private Key");
         let ccc = *hash_value.last_chunk::<32>().unwrap();
-        let cpk = nssa::PublicKey::new_from_private_key(&csk);
+        let cpk = nssa_core::PublicKey::new_from_private_key(&csk);
 
         Self {
             csk,
@@ -61,7 +61,7 @@ impl KeyNode for ChildKeysPublic {
     fn nth_child(&self, cci: u32) -> Self {
         let hash_value = self.compute_hash_value(cci);
 
-        let csk = nssa::PrivateKey::try_new({
+        let csk = nssa_core::PrivateKey::try_new({
             let hash_value = hash_value
                 .first_chunk::<32>()
                 .expect("hash_value is 64 bytes, must be safe to get first 32");
@@ -80,7 +80,7 @@ impl KeyNode for ChildKeysPublic {
             .last_chunk::<32>()
             .expect("hash_value is 64 bytes, must be safe to get last 32");
 
-        let cpk = nssa::PublicKey::new_from_private_key(&csk);
+        let cpk = nssa_core::PublicKey::new_from_private_key(&csk);
 
         Self {
             csk,
@@ -99,7 +99,7 @@ impl KeyNode for ChildKeysPublic {
     }
 
     fn account_id(&self) -> nssa::AccountId {
-        nssa::AccountId::from(&self.cpk)
+        nssa::AccountId::public_account_id(&self.cpk)
     }
 }
 
@@ -107,7 +107,7 @@ impl KeyNode for ChildKeysPublic {
     clippy::single_char_lifetime_names,
     reason = "TODO add meaningful name"
 )]
-impl<'a> From<&'a ChildKeysPublic> for &'a nssa::PrivateKey {
+impl<'a> From<&'a ChildKeysPublic> for &'a nssa_core::PrivateKey {
     fn from(value: &'a ChildKeysPublic) -> Self {
         &value.csk
     }
@@ -115,7 +115,7 @@ impl<'a> From<&'a ChildKeysPublic> for &'a nssa::PrivateKey {
 
 #[cfg(test)]
 mod tests {
-    use nssa::{PrivateKey, PublicKey};
+    use nssa_core::{PrivateKey, PublicKey};
 
     use super::*;
 
diff --git a/key_protocol/src/key_management/key_tree/mod.rs b/key_protocol/src/key_management/key_tree/mod.rs
index 08a576e5..c9db4d2d 100644
--- a/key_protocol/src/key_management/key_tree/mod.rs
+++ b/key_protocol/src/key_management/key_tree/mod.rs
@@ -212,7 +212,7 @@ impl KeyTree<ChildKeysPrivate> {
             println!("Cleanup of tree at depth {i}");
             for id in ChainIndex::chain_ids_at_depth(i) {
                 if let Some(node) = self.key_map.get(&id) {
-                    if node.value.1 == nssa::Account::default() {
+                    if node.value.account == nssa::Account::default() {
                         let addr = node.account_id();
                         self.remove(addr);
                     } else {
@@ -478,25 +478,25 @@ mod tests {
             .key_map
             .get_mut(&ChainIndex::from_str("/1").unwrap())
             .unwrap();
-        acc.value.1.balance = 2;
+        acc.value.account.balance = 2;
 
         let acc = tree
             .key_map
             .get_mut(&ChainIndex::from_str("/2").unwrap())
             .unwrap();
-        acc.value.1.balance = 3;
+        acc.value.account.balance = 3;
 
         let acc = tree
             .key_map
             .get_mut(&ChainIndex::from_str("/0/1").unwrap())
             .unwrap();
-        acc.value.1.balance = 5;
+        acc.value.account.balance = 5;
 
         let acc = tree
             .key_map
             .get_mut(&ChainIndex::from_str("/1/0").unwrap())
             .unwrap();
-        acc.value.1.balance = 6;
+        acc.value.account.balance = 6;
 
         tree.cleanup_tree_remove_uninit_layered(10);
 
@@ -518,15 +518,15 @@ mod tests {
         assert_eq!(key_set, key_set_res);
 
         let acc = &tree.key_map[&ChainIndex::from_str("/1").unwrap()];
-        assert_eq!(acc.value.1.balance, 2);
+        assert_eq!(acc.value.account.balance, 2);
 
         let acc = &tree.key_map[&ChainIndex::from_str("/2").unwrap()];
-        assert_eq!(acc.value.1.balance, 3);
+        assert_eq!(acc.value.account.balance, 3);
 
         let acc = &tree.key_map[&ChainIndex::from_str("/0/1").unwrap()];
-        assert_eq!(acc.value.1.balance, 5);
+        assert_eq!(acc.value.account.balance, 5);
 
         let acc = &tree.key_map[&ChainIndex::from_str("/1/0").unwrap()];
-        assert_eq!(acc.value.1.balance, 6);
+        assert_eq!(acc.value.account.balance, 6);
     }
 }
diff --git a/key_protocol/src/key_management/mod.rs b/key_protocol/src/key_management/mod.rs
index c038c415..d17c23a2 100644
--- a/key_protocol/src/key_management/mod.rs
+++ b/key_protocol/src/key_management/mod.rs
@@ -125,11 +125,11 @@ mod tests {
         let nullifier_public_key = utxo_secret_key_holder.generate_nullifier_public_key();
         let viewing_public_key = utxo_secret_key_holder.generate_viewing_public_key();
 
-        let pub_account_signing_key = nssa::PrivateKey::new_os_random();
+        let pub_account_signing_key = nssa_core::PrivateKey::new_os_random();
 
-        let public_key = nssa::PublicKey::new_from_private_key(&pub_account_signing_key);
+        let public_key = nssa_core::PublicKey::new_from_private_key(&pub_account_signing_key);
 
-        let account = nssa::AccountId::from(&public_key);
+        let account = nssa::AccountId::public_account_id(&public_key);
 
         println!("======Prerequisites======");
         println!();
@@ -178,7 +178,7 @@ mod tests {
             .get_node(second_child_id)
             .unwrap()
             .value
-            .0
+            .key_chain
             .clone()
     }
 
diff --git a/key_protocol/src/key_protocol_core/mod.rs b/key_protocol/src/key_protocol_core/mod.rs
index bb771331..e2910a05 100644
--- a/key_protocol/src/key_protocol_core/mod.rs
+++ b/key_protocol/src/key_protocol_core/mod.rs
@@ -2,6 +2,7 @@ use std::collections::BTreeMap;
 
 use anyhow::Result;
 use k256::AffinePoint;
+use nssa_core::account::Identifier;
 use serde::{Deserialize, Serialize};
 
 use crate::key_management::{
@@ -27,12 +28,13 @@ pub struct NSSAUserData {
 /// TODO: eventually, this should have `sign_key: Option<PrivateKey>` and `pub_key: PublicKey`.
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct PublicBundle {
-    pub sign_key: nssa::PrivateKey,
+    pub sign_key: nssa_core::PrivateKey,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct PrivateBundle {
     pub key_chain: KeyChain,
+    pub identifier: Identifier,
     pub account: nssa_core::account::Account,
 }
 
@@ -42,8 +44,8 @@ impl NSSAUserData {
     ) -> bool {
         let mut check_res = true;
         for (account_id, public_bundle) in accounts_keys_map {
-            let expected_account_id = nssa::AccountId::from(
-                &nssa::PublicKey::new_from_private_key(&public_bundle.sign_key),
+            let expected_account_id = nssa::AccountId::public_account_id(
+                &nssa_core::PublicKey::new_from_private_key(&public_bundle.sign_key),
             );
             if &expected_account_id != account_id {
                 println!("{expected_account_id}, {account_id}");
@@ -58,7 +60,10 @@ impl NSSAUserData {
     ) -> bool {
         let mut check_res = true;
         for (account_id, bundle) in accounts_keys_map {
-            let expected_account_id = nssa::AccountId::from(&bundle.key_chain.nullifier_public_key);
+            let expected_account_id = nssa::AccountId::private_account_id(
+                &bundle.key_chain.nullifier_public_key,
+                bundle.identifier,
+            );
             if expected_account_id != *account_id {
                 println!("{expected_account_id}, {account_id}");
                 check_res = false;
@@ -117,7 +122,7 @@ impl NSSAUserData {
     pub fn get_pub_account_signing_key(
         &self,
         account_id: nssa::AccountId,
-    ) -> Option<&nssa::PrivateKey> {
+    ) -> Option<&nssa_core::PrivateKey> {
         self.default_pub_account_signing_keys
             .get(&account_id)
             .map(|bundle| &bundle.sign_key)
@@ -153,8 +158,9 @@ impl NSSAUserData {
                 self.private_key_tree
                     .get_node(account_id)
                     .map(|child_keys_private| PrivateBundle {
-                        key_chain: child_keys_private.value.0.clone(),
-                        account: child_keys_private.value.1.clone(),
+                        key_chain: child_keys_private.value.key_chain.clone(),
+                        identifier: child_keys_private.value.identifier,
+                        account: child_keys_private.value.account.clone(),
                     })
             })
     }
diff --git a/nssa/Cargo.toml b/nssa/Cargo.toml
index d8f0807c..29346b30 100644
--- a/nssa/Cargo.toml
+++ b/nssa/Cargo.toml
@@ -8,7 +8,7 @@ license = { workspace = true }
 workspace = true
 
 [dependencies]
-nssa_core = { workspace = true, features = ["host"] }
+nssa_core = { workspace = true, features = ["host", "test-utils"] }
 clock_core.workspace = true
 
 anyhow.workspace = true
diff --git a/nssa/core/Cargo.toml b/nssa/core/Cargo.toml
index d9e80af4..9fd0e983 100644
--- a/nssa/core/Cargo.toml
+++ b/nssa/core/Cargo.toml
@@ -12,10 +12,12 @@ risc0-zkvm.workspace = true
 borsh.workspace = true
 serde.workspace = true
 serde_with.workspace = true
+rand.workspace = true
 thiserror.workspace = true
 bytemuck.workspace = true
 bytesize.workspace = true
 base58.workspace = true
+hex.workspace = true
 k256 = { workspace = true, optional = true }
 chacha20 = { version = "0.10" }
 
@@ -23,5 +25,6 @@ chacha20 = { version = "0.10" }
 serde_json.workspace = true
 
 [features]
-default = []
+default = ["dep:k256"]
 host = ["dep:k256"]
+test-utils = ["dep:k256"]
diff --git a/nssa/core/src/account.rs b/nssa/core/src/account.rs
index 0f9248e3..52dc0fc6 100644
--- a/nssa/core/src/account.rs
+++ b/nssa/core/src/account.rs
@@ -6,16 +6,21 @@ use std::{
 use base58::{FromBase58 as _, ToBase58 as _};
 use borsh::{BorshDeserialize, BorshSerialize};
 pub use data::Data;
+use rand::{RngCore as _, rngs::OsRng};
 use risc0_zkvm::sha::{Impl, Sha256 as _};
 use serde::{Deserialize, Serialize};
 use serde_with::{DeserializeFromStr, SerializeDisplay};
 
-use crate::{NullifierPublicKey, NullifierSecretKey, program::ProgramId};
+use crate::{
+    EphemeralPublicKey, NullifierPublicKey, NullifierSecretKey, PublicKey, program::ProgramId,
+};
 
 pub mod data;
 
 #[derive(Copy, Debug, Default, Clone, Eq, PartialEq)]
 pub struct Nonce(pub u128);
+#[derive(Copy, Debug, Clone, Default, Eq, PartialEq, Serialize, Deserialize)]
+pub struct Identifier(pub u128);
 
 impl Nonce {
     pub const fn public_account_nonce_increment(&mut self) {
@@ -91,6 +96,30 @@ impl BorshDeserialize for Nonce {
 
 pub type Balance = u128;
 
+impl Identifier {
+    #[must_use]
+    pub fn private_identifier(epk: &EphemeralPublicKey, index: u8) -> Self {
+        const PRIVATE_ACCOUNT_ID_PREFIX: &[u8; 32] = b"/LEE/v0.3/AccountId/Identifier/\x00";
+
+        let mut bytes = Vec::<u8>::new();
+        bytes.extend_from_slice(PRIVATE_ACCOUNT_ID_PREFIX);
+        bytes.extend_from_slice(&epk.0);
+        bytes.extend_from_slice(&[index]);
+
+        let mut value = [0_u8; 16];
+        value.copy_from_slice(&Impl::hash_bytes(&bytes).as_bytes()[0..16]);
+
+        Self(u128::from_le_bytes(value))
+    }
+
+    #[must_use]
+    pub fn new_os_random() -> Self {
+        let mut bytes = [0_u8; 16];
+        OsRng.fill_bytes(&mut bytes);
+        Self(u128::from_le_bytes(bytes))
+    }
+}
+
 /// Account to be used both in public and private contexts.
 #[derive(
     Default, Clone, Eq, PartialEq, Serialize, Deserialize, BorshSerialize, BorshDeserialize,
@@ -130,11 +159,12 @@ pub struct AccountWithMetadata {
 
 #[cfg(feature = "host")]
 impl AccountWithMetadata {
-    pub fn new(account: Account, is_authorized: bool, account_id: impl Into<AccountId>) -> Self {
+    #[must_use]
+    pub const fn new(account: Account, is_authorized: bool, account_id: AccountId) -> Self {
         Self {
             account,
             is_authorized,
-            account_id: account_id.into(),
+            account_id,
         }
     }
 }
@@ -177,6 +207,42 @@ impl AccountId {
     pub const fn into_value(self) -> [u8; 32] {
         self.value
     }
+
+    #[must_use]
+    pub fn private_account_id(npk: &NullifierPublicKey, identifier: Identifier) -> Self {
+        const PRIVATE_ACCOUNT_ID_PREFIX: &[u8; 32] =
+            b"/LEE/v0.3/AccountId/Private/\x00\x00\x00\x00";
+
+        let mut bytes = Vec::<u8>::new();
+        bytes.extend_from_slice(PRIVATE_ACCOUNT_ID_PREFIX);
+        bytes.extend_from_slice(&npk.0);
+        bytes.extend_from_slice(&identifier.0.to_le_bytes());
+
+        Self::new(
+            Impl::hash_bytes(&bytes)
+                .as_bytes()
+                .try_into()
+                .expect("Conversion should not fail"),
+        )
+    }
+
+    #[must_use]
+    pub fn public_account_id(value: &PublicKey) -> Self {
+        const PUBLIC_ACCOUNT_ID_PREFIX: &[u8; 32] =
+            b"/LEE/v0.3/AccountId/Public/\x00\x00\x00\x00\x00";
+
+        let mut bytes = Vec::<u8>::new();
+        bytes.extend_from_slice(PUBLIC_ACCOUNT_ID_PREFIX);
+        bytes.extend_from_slice(value.value());
+        // bytes.extend_from_slice(&identifier.0.to_le_bytes());
+
+        Self::new(
+            Impl::hash_bytes(&bytes)
+                .as_bytes()
+                .try_into()
+                .expect("Conversion should not fail"),
+        )
+    }
 }
 
 impl AsRef<[u8]> for AccountId {
@@ -351,4 +417,57 @@ mod tests {
 
         assert_eq!(nonce, nonce_restored);
     }
+
+    #[test]
+    fn account_id_from_nullifier_public_key() {
+        let nsk = [
+            57, 5, 64, 115, 153, 56, 184, 51, 207, 238, 99, 165, 147, 214, 213, 151, 30, 251, 30,
+            196, 134, 22, 224, 211, 237, 120, 136, 225, 188, 220, 249, 28,
+        ];
+        let npk = NullifierPublicKey::from(&nsk);
+        let expected_account_id = AccountId::new([
+            48, 66, 236, 142, 62, 81, 247, 114, 151, 55, 109, 108, 34, 132, 216, 182, 239, 250,
+            126, 85, 106, 222, 127, 193, 125, 168, 62, 150, 129, 194, 135, 114,
+        ]);
+
+        let identifier = Identifier(13_u128);
+
+        let account_id = AccountId::private_account_id(&npk, identifier);
+
+        assert_eq!(account_id, expected_account_id);
+    }
+
+    #[test]
+    fn account_id_from_public_key() {
+        let pub_key = PublicKey::try_new([42_u8; 32]).expect("Expect valid Public Key");
+
+        let expected_account_id = AccountId::new([
+            55, 223, 166, 27, 166, 126, 71, 128, 222, 225, 215, 176, 98, 21, 215, 13, 71, 74, 13,
+            72, 200, 175, 25, 19, 96, 160, 250, 230, 45, 15, 254, 134,
+        ]);
+
+        let account_id = AccountId::public_account_id(&pub_key);
+
+        assert_eq!(account_id, expected_account_id);
+    }
+
+    #[test]
+    fn identifier_from_ephemeral_public_key() {
+        let epk = EphemeralPublicKey::from_scalar([
+            185, 147, 32, 242, 145, 91, 123, 77, 42, 33, 134, 84, 12, 165, 117, 70, 158, 201, 95,
+            153, 14, 12, 92, 235, 128, 156, 194, 169, 68, 35, 165, 127,
+        ]);
+
+        let expected_identifier = Identifier(u128::from_le_bytes([
+            170, 216, 75, 182, 85, 117, 119, 230, 115, 121, 70, 204, 104, 96, 182, 122,
+        ]));
+        let identifier = Identifier::private_identifier(&epk, 13_u8);
+
+        assert_eq!(identifier, expected_identifier);
+    }
+
+    #[test]
+    fn default_identifier() {
+        assert_eq!(0_u128, Identifier::default().0);
+    }
 }
diff --git a/nssa/core/src/circuit_io.rs b/nssa/core/src/circuit_io.rs
index 998f6d71..265ae049 100644
--- a/nssa/core/src/circuit_io.rs
+++ b/nssa/core/src/circuit_io.rs
@@ -3,7 +3,7 @@ use serde::{Deserialize, Serialize};
 use crate::{
     Commitment, CommitmentSetDigest, MembershipProof, Nullifier, NullifierPublicKey,
     NullifierSecretKey, SharedSecretKey,
-    account::{Account, AccountWithMetadata},
+    account::{Account, AccountWithMetadata, Identifier},
     encryption::Ciphertext,
     program::{BlockValidityWindow, ProgramId, ProgramOutput, TimestampValidityWindow},
 };
@@ -22,6 +22,8 @@ pub struct PrivacyPreservingCircuitInput {
     pub private_account_keys: Vec<(NullifierPublicKey, SharedSecretKey)>,
     /// Nullifier secret keys for authorized private accounts.
     pub private_account_nsks: Vec<NullifierSecretKey>,
+    /// Identifiers used to generate `AccountId`.
+    pub private_account_identifiers: Vec<Identifier>,
     /// Membership proofs for private accounts. Can be [`None`] for uninitialized accounts.
     pub private_account_membership_proofs: Vec<Option<MembershipProof>>,
     /// Program ID.
@@ -57,7 +59,7 @@ mod tests {
     use super::*;
     use crate::{
         Commitment, Nullifier, NullifierPublicKey,
-        account::{Account, AccountId, AccountWithMetadata, Nonce},
+        account::{Account, AccountId, AccountWithMetadata, Identifier, Nonce},
     };
 
     #[test]
@@ -93,12 +95,21 @@ mod tests {
             }],
             ciphertexts: vec![Ciphertext(vec![255, 255, 1, 1, 2, 2])],
             new_commitments: vec![Commitment::new(
-                &NullifierPublicKey::from(&[1; 32]),
+                &AccountId::private_account_id(
+                    &NullifierPublicKey::from(&[1_u8; 32]),
+                    Identifier(0_u128),
+                ),
                 &Account::default(),
             )],
             new_nullifiers: vec![(
                 Nullifier::for_account_update(
-                    &Commitment::new(&NullifierPublicKey::from(&[2; 32]), &Account::default()),
+                    &Commitment::new(
+                        &AccountId::private_account_id(
+                            &NullifierPublicKey::from(&[2_u8; 32]),
+                            Identifier(0_u128),
+                        ),
+                        &Account::default(),
+                    ),
                     &[1; 32],
                 ),
                 [0xab; 32],
diff --git a/nssa/core/src/commitment.rs b/nssa/core/src/commitment.rs
index 24d5de87..7a87491b 100644
--- a/nssa/core/src/commitment.rs
+++ b/nssa/core/src/commitment.rs
@@ -2,7 +2,7 @@ use borsh::{BorshDeserialize, BorshSerialize};
 use risc0_zkvm::sha::{Impl, Sha256 as _};
 use serde::{Deserialize, Serialize};
 
-use crate::{NullifierPublicKey, account::Account};
+use crate::account::{Account, AccountId};
 
 /// A commitment to all zero data.
 /// ```python
@@ -50,15 +50,15 @@ impl std::fmt::Debug for Commitment {
 
 impl Commitment {
     /// Generates the commitment to a private account owned by user for npk:
-    /// SHA256( `Comm_DS` || npk || `program_owner` || balance || nonce || SHA256(data)).
+    /// SHA256( `Comm_DS` || `account_id` || `program_owner` || balance || nonce || SHA256(data)).
     #[must_use]
-    pub fn new(npk: &NullifierPublicKey, account: &Account) -> Self {
+    pub fn new(account_id: &AccountId, account: &Account) -> Self {
         const COMMITMENT_PREFIX: &[u8; 32] =
             b"/LEE/v0.3/Commitment/\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
 
         let mut bytes = Vec::new();
         bytes.extend_from_slice(COMMITMENT_PREFIX);
-        bytes.extend_from_slice(&npk.to_byte_array());
+        bytes.extend_from_slice(account_id.value());
         let account_bytes_with_hashed_data = {
             let mut this = Vec::new();
             for word in &account.program_owner {
@@ -115,14 +115,15 @@ mod tests {
     use risc0_zkvm::sha::{Impl, Sha256 as _};
 
     use crate::{
-        Commitment, DUMMY_COMMITMENT, DUMMY_COMMITMENT_HASH, NullifierPublicKey, account::Account,
+        Commitment, DUMMY_COMMITMENT, DUMMY_COMMITMENT_HASH,
+        account::{Account, AccountId},
     };
 
     #[test]
     fn nothing_up_my_sleeve_dummy_commitment() {
         let default_account = Account::default();
-        let npk_null = NullifierPublicKey([0; 32]);
-        let expected_dummy_commitment = Commitment::new(&npk_null, &default_account);
+        let account_id = AccountId::new([0; 32]);
+        let expected_dummy_commitment = Commitment::new(&account_id, &default_account);
         assert_eq!(DUMMY_COMMITMENT, expected_dummy_commitment);
     }
 
diff --git a/nssa/core/src/encryption/mod.rs b/nssa/core/src/encryption/mod.rs
index 400fb331..9832d972 100644
--- a/nssa/core/src/encryption/mod.rs
+++ b/nssa/core/src/encryption/mod.rs
@@ -5,11 +5,11 @@ use chacha20::{
 };
 use risc0_zkvm::sha::{Impl, Sha256 as _};
 use serde::{Deserialize, Serialize};
+pub use shared_key_derivation::EphemeralPublicKey;
 #[cfg(feature = "host")]
-pub use shared_key_derivation::{EphemeralPublicKey, EphemeralSecretKey, ViewingPublicKey};
+pub use shared_key_derivation::{EphemeralSecretKey, ViewingPublicKey};
 
 use crate::{Commitment, account::Account};
-#[cfg(feature = "host")]
 pub mod shared_key_derivation;
 
 pub type Scalar = [u8; 32];
diff --git a/nssa/core/src/error.rs b/nssa/core/src/error.rs
index 8f053233..feddade4 100644
--- a/nssa/core/src/error.rs
+++ b/nssa/core/src/error.rs
@@ -9,4 +9,13 @@ pub enum NssaCoreError {
 
     #[error("IO error: {0}")]
     Io(#[from] io::Error),
+
+    #[error("Invalid Public Key")]
+    InvalidPublicKey(#[source] k256::schnorr::Error),
+
+    #[error("Invalid hex for public key")]
+    InvalidHexPublicKey(hex::FromHexError),
+
+    #[error("Invalid private key")]
+    InvalidPrivateKey,
 }
diff --git a/nssa/core/src/lib.rs b/nssa/core/src/lib.rs
index a4fcdee1..5d6c44cd 100644
--- a/nssa/core/src/lib.rs
+++ b/nssa/core/src/lib.rs
@@ -8,8 +8,11 @@ pub use commitment::{
     Commitment, CommitmentSetDigest, DUMMY_COMMITMENT, DUMMY_COMMITMENT_HASH, MembershipProof,
     compute_digest_for_path,
 };
-pub use encryption::{EncryptionScheme, SharedSecretKey};
+pub use encryption::{
+    EncryptionScheme, SharedSecretKey, shared_key_derivation::EphemeralPublicKey,
+};
 pub use nullifier::{Nullifier, NullifierPublicKey, NullifierSecretKey};
+pub use signature::{PrivateKey, PublicKey, Signature};
 
 pub mod account;
 mod circuit_io;
@@ -18,8 +21,9 @@ mod encoding;
 pub mod encryption;
 mod nullifier;
 pub mod program;
+pub mod signature;
 
-#[cfg(feature = "host")]
+// TODO: temp#[cfg(feature = "host")]
 pub mod error;
 
 pub type BlockId = u64;
diff --git a/nssa/core/src/nullifier.rs b/nssa/core/src/nullifier.rs
index 0e15ec74..66299d2a 100644
--- a/nssa/core/src/nullifier.rs
+++ b/nssa/core/src/nullifier.rs
@@ -8,23 +8,6 @@ use crate::{Commitment, account::AccountId};
 #[cfg_attr(any(feature = "host", test), derive(Clone, Hash))]
 pub struct NullifierPublicKey(pub [u8; 32]);
 
-impl From<&NullifierPublicKey> for AccountId {
-    fn from(value: &NullifierPublicKey) -> Self {
-        const PRIVATE_ACCOUNT_ID_PREFIX: &[u8; 32] =
-            b"/LEE/v0.3/AccountId/Private/\x00\x00\x00\x00";
-
-        let mut bytes = [0; 64];
-        bytes[0..32].copy_from_slice(PRIVATE_ACCOUNT_ID_PREFIX);
-        bytes[32..].copy_from_slice(&value.0);
-        Self::new(
-            Impl::hash_bytes(&bytes)
-                .as_bytes()
-                .try_into()
-                .expect("Conversion should not fail"),
-        )
-    }
-}
-
 impl AsRef<[u8]> for NullifierPublicKey {
     fn as_ref(&self) -> &[u8] {
         self.0.as_slice()
@@ -85,10 +68,10 @@ impl Nullifier {
 
     /// Computes a nullifier for an account initialization.
     #[must_use]
-    pub fn for_account_initialization(npk: &NullifierPublicKey) -> Self {
+    pub fn for_account_initialization(account_id: &AccountId) -> Self {
         const INIT_PREFIX: &[u8; 32] = b"/LEE/v0.3/Nullifier/Initialize/\x00";
         let mut bytes = INIT_PREFIX.to_vec();
-        bytes.extend_from_slice(&npk.to_byte_array());
+        bytes.extend_from_slice(account_id.value());
         Self(Impl::hash_bytes(&bytes).as_bytes().try_into().unwrap())
     }
 }
@@ -96,6 +79,7 @@ impl Nullifier {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::account::Identifier;
 
     #[test]
     fn constructor_for_account_update() {
@@ -115,11 +99,16 @@ mod tests {
             112, 188, 193, 129, 150, 55, 228, 67, 88, 168, 29, 151, 5, 92, 23, 190, 17, 162, 164,
             255, 29, 105, 42, 186, 43, 11, 157, 168, 132, 225, 17, 163,
         ]);
+
+        let identifier = Identifier(0_u128);
+
+        let account_id = AccountId::private_account_id(&npk, identifier);
+
         let expected_nullifier = Nullifier([
-            149, 59, 95, 181, 2, 194, 20, 143, 72, 233, 104, 243, 59, 70, 67, 243, 110, 77, 109,
-            132, 139, 111, 51, 125, 128, 92, 107, 46, 252, 4, 20, 149,
+            63, 58, 51, 159, 15, 100, 240, 243, 60, 143, 151, 108, 116, 144, 101, 6, 134, 72, 198,
+            249, 108, 80, 237, 194, 143, 66, 225, 191, 111, 49, 66, 54,
         ]);
-        let nullifier = Nullifier::for_account_initialization(&npk);
+        let nullifier = Nullifier::for_account_initialization(&account_id);
         assert_eq!(nullifier, expected_nullifier);
     }
 
@@ -136,21 +125,4 @@ mod tests {
         let npk = NullifierPublicKey::from(&nsk);
         assert_eq!(npk, expected_npk);
     }
-
-    #[test]
-    fn account_id_from_nullifier_public_key() {
-        let nsk = [
-            57, 5, 64, 115, 153, 56, 184, 51, 207, 238, 99, 165, 147, 214, 213, 151, 30, 251, 30,
-            196, 134, 22, 224, 211, 237, 120, 136, 225, 188, 220, 249, 28,
-        ];
-        let npk = NullifierPublicKey::from(&nsk);
-        let expected_account_id = AccountId::new([
-            139, 72, 194, 222, 215, 187, 147, 56, 55, 35, 222, 205, 156, 12, 204, 227, 166, 44, 30,
-            81, 186, 14, 167, 234, 28, 236, 32, 213, 125, 251, 193, 233,
-        ]);
-
-        let account_id = AccountId::from(&npk);
-
-        assert_eq!(account_id, expected_account_id);
-    }
 }
diff --git a/nssa/core/src/signature/bip340_test_vectors.rs b/nssa/core/src/signature/bip340_test_vectors.rs
new file mode 100644
index 00000000..e316db5e
--- /dev/null
+++ b/nssa/core/src/signature/bip340_test_vectors.rs
@@ -0,0 +1,367 @@
+use crate::{PrivateKey, PublicKey, Signature};
+
+pub struct TestVector {
+    pub seckey: Option<PrivateKey>,
+    pub pubkey: PublicKey,
+    pub aux_rand: Option<[u8; 32]>,
+    pub message: Option<Vec<u8>>,
+    pub signature: Signature,
+    pub verification_result: bool,
+}
+
+/// Test vectors from
+/// <https://github.com/bitcoin/bips/blob/master/bip-0340/test-vectors.csv>.
+//
+pub fn test_vectors() -> Vec<TestVector> {
+    vec![
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0000000000000000000000000000000000000000000000000000000000000003",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BCE036F9",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000000",
+            )),
+            message: Some(
+                hex::decode("0000000000000000000000000000000000000000000000000000000000000000")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "E907831F80848D1069A5371B402410364BDF1C5F8307B0084C55F1CE2DCA821525F66A4A85EA8B71E482A74F382D2CE5EBEEE8FDB2172F477DF4900D310536C0",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "B7E151628AED2A6ABF7158809CF4F3C762E7160F38B4DA56A784D9045190CFEF",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000001",
+            )),
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "6896BD60EEAE296DB48A229FF71DFE071BDE413E6D43F917DC8DCF8C78DE33418906D11AC976ABCCB20B091292BFF4EA897EFCB639EA871CFA95F6DE339E4B0A",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "C90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B14E5C9",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DD308AFEC5777E13121FA72B9CC1B7CC0139715309B086C960E18FD969774EB8",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "C87AA53824B4D7AE2EB035A2B5BBBCCC080E76CDC6D1692C4B0B62D798E6D906",
+            )),
+            message: Some(
+                hex::decode("7E2D58D8B3BCDF1ABADEC7829054F90DDA9805AAB56C77333024B9D0A508B75C")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "5831AAEED7B44BB74E5EAB94BA9D4294C49BCF2A60728D8B4C200F50DD313C1BAB745879A5AD954A72C45A91C3A51D3C7ADEA98D82F8481E0E1E03674A6F3FB7",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0B432B2677937381AEF05BB02A66ECD012773062CF3FA2549E44F58ED2401710",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "25D1DFF95105F5253C4022F628A996AD3A0D95FBF21D468A1B33F8C160D8F517",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
+            )),
+            message: Some(
+                hex::decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "7EB0509757E246F19449885651611CB965ECC1A187DD51B64FDA1EDC9637D5EC97582B9CB13DB3933705B32BA982AF5AF25FD78881EBB32771FC5922EFC66EA3",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "D69C3509BB99E412E68B0FE8544E72837DFA30746D8BE2AA65975F29D22DC7B9",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("4DF3C3F68FCC83B27E9D42C90431A72499F17875C81A599B566C9889B9696703")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "00000000000000000000003B78CE563F89A0ED9414F5AA28AD0D96D6795F9C6376AFB1548AF603B3EB45C9F8207DEE1060CB71C04E80F593060B07D28308D7F4",
+                ),
+            },
+            verification_result: true,
+        },
+        // Test with invalid public key
+        // TestVector {
+        //     seckey: None,
+        //     pubkey: PublicKey::new(hex_to_bytes(
+        //                     "EEFDEA4CDB677750A420FEE807EACF21EB9898AE79B9768766E4FAA04A2D4A34",
+        //                 )).unwrap(),
+        //     aux_rand: None,
+        //     message: Some(
+        //                     hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89").unwrap(),
+        //                 ),
+        //     signature: Signature {
+        //                     value: hex_to_bytes(
+        //                         "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E17776969E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
+        //                     ),
+        //                 },
+        //     verification_result: false,
+        // },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "FFF97BD5755EEEA420453A14355235D382F6472F8568A18B2F057A14602975563CC27944640AC607CD107AE10923D9EF7A73C643E166BE5EBEAFA34B1AC553E2",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "1FA62E331EDBC21C394792D2AB1100A7B432B013DF3F6FF4F99FCB33E0E1515F28890B3EDB6E7189B630448B515CE4F8622A954CFE545735AAEA5134FCCDB2BD",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E177769961764B3AA9B2FFCB6EF947B6887A226E8D7C93E00C5ED0C1834FF0D0C2E6DA6",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "0000000000000000000000000000000000000000000000000000000000000000123DDA8328AF9C23A94C1FEECFD123BA4FB73476F0D594DCB65C6425BD186051",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "00000000000000000000000000000000000000000000000000000000000000017615FBAF5AE28864013C099742DEADB4DBA87F11AC6754F93780D5A1837CF197",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "4A298DACAE57395A15D0795DDBFD1DCB564DA82B0F269BC70A74F8220429BA1D69E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F69E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
+                ),
+            },
+            verification_result: false,
+        },
+        TestVector {
+            seckey: None,
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B502BA659",
+            )).unwrap(),
+            aux_rand: None,
+            message: Some(
+                hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89")
+                    .unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E177769FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141",
+                ),
+            },
+            verification_result: false,
+        },
+        // Test with invalid public key
+        // TestVector {
+        //     seckey: None,
+        //     pubkey: PublicKey::new(hex_to_bytes(
+        //                     "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC30",
+        //                 )).unwrap(),
+        //     aux_rand: None,
+        //     message: Some(
+        //                     hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89").unwrap(),
+        //                 ),
+        //     signature: Signature {
+        //                     value: hex_to_bytes(
+        //                         "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E17776969E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
+        //                     ),
+        //                 },
+        //     verification_result: false,
+        // },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0340034003400340034003400340034003400340034003400340034003400340",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000000",
+            )),
+            message: None,
+            signature: Signature {
+                value: hex_to_bytes(
+                    "71535DB165ECD9FBBC046E5FFAEA61186BB6AD436732FCCC25291A55895464CF6069CE26BF03466228F19A3A62DB8A649F2D560FAC652827D1AF0574E427AB63",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0340034003400340034003400340034003400340034003400340034003400340",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000000",
+            )),
+            message: Some(hex::decode("11").unwrap()),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "08A20A0AFEF64124649232E0693C583AB1B9934AE63B4C3511F3AE1134C6A303EA3173BFEA6683BD101FA5AA5DBC1996FE7CACFC5A577D33EC14564CEC2BACBF",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0340034003400340034003400340034003400340034003400340034003400340",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000000",
+            )),
+            message: Some(hex::decode("0102030405060708090A0B0C0D0E0F1011").unwrap()),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "5130F39A4059B43BC7CAC09A19ECE52B5D8699D1A71E3C52DA9AFDB6B50AC370C4A482B77BF960F8681540E25B6771ECE1E5A37FD80E5A51897C5566A97EA5A5",
+                ),
+            },
+            verification_result: true,
+        },
+        TestVector {
+            seckey: Some(PrivateKey::try_new(hex_to_bytes(
+                "0340034003400340034003400340034003400340034003400340034003400340",
+            )).unwrap()),
+            pubkey: PublicKey::try_new(hex_to_bytes(
+                "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
+            )).unwrap(),
+            aux_rand: Some(hex_to_bytes::<32>(
+                "0000000000000000000000000000000000000000000000000000000000000000",
+            )),
+            message: Some(
+                hex::decode("99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999").unwrap(),
+            ),
+            signature: Signature {
+                value: hex_to_bytes(
+                    "403B12B0D8555A344175EA7EC746566303321E5DBFA8BE6F091635163ECA79A8585ED3E3170807E7C03B720FC54C7B23897FCBA0E9D0B4A06894CFD249F22367",
+                ),
+            },
+            verification_result: true,
+        },
+    ]
+}
+
+fn hex_to_bytes<const N: usize>(hex: &str) -> [u8; N] {
+    hex::decode(hex).unwrap().try_into().unwrap()
+}
diff --git a/nssa/core/src/signature/mod.rs b/nssa/core/src/signature/mod.rs
new file mode 100644
index 00000000..467c5048
--- /dev/null
+++ b/nssa/core/src/signature/mod.rs
@@ -0,0 +1,127 @@
+use std::str::FromStr;
+
+use borsh::{BorshDeserialize, BorshSerialize};
+pub use private_key::PrivateKey;
+pub use public_key::PublicKey;
+use rand::{RngCore as _, rngs::OsRng};
+
+mod private_key;
+mod public_key;
+
+#[derive(Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
+pub struct Signature {
+    pub value: [u8; 64],
+}
+
+impl std::fmt::Debug for Signature {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
+    }
+}
+
+impl std::fmt::Display for Signature {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", hex::encode(self.value))
+    }
+}
+
+impl FromStr for Signature {
+    type Err = hex::FromHexError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut bytes = [0_u8; 64];
+        hex::decode_to_slice(s, &mut bytes)?;
+        Ok(Self { value: bytes })
+    }
+}
+
+impl Signature {
+    #[must_use]
+    pub fn new(key: &PrivateKey, message: &[u8]) -> Self {
+        let mut aux_random = [0_u8; 32];
+        OsRng.fill_bytes(&mut aux_random);
+        Self::new_with_aux_random(key, message, aux_random)
+    }
+
+    pub(crate) fn new_with_aux_random(
+        key: &PrivateKey,
+        message: &[u8],
+        aux_random: [u8; 32],
+    ) -> Self {
+        let value = {
+            let signing_key = k256::schnorr::SigningKey::from_bytes(key.value())
+                .expect("Expect valid signing key");
+            signing_key
+                .sign_raw(message, &aux_random)
+                .expect("Expect to produce a valid signature")
+                .to_bytes()
+        };
+
+        Self { value }
+    }
+
+    #[must_use]
+    pub fn is_valid_for(&self, bytes: &[u8], public_key: &PublicKey) -> bool {
+        let Ok(pk) = k256::schnorr::VerifyingKey::from_bytes(public_key.value()) else {
+            return false;
+        };
+
+        let Ok(sig) = k256::schnorr::Signature::try_from(self.value.as_slice()) else {
+            return false;
+        };
+
+        pk.verify_raw(bytes, &sig).is_ok()
+    }
+
+    #[cfg(feature = "test-utils")]
+    #[must_use]
+    pub const fn new_for_tests(value: [u8; 64]) -> Self {
+        Self { value }
+    }
+}
+
+#[cfg(test)]
+mod bip340_test_vectors;
+
+#[cfg(test)]
+mod tests {
+
+    use crate::{Signature, signature::bip340_test_vectors};
+
+    #[test]
+    fn signature_generation_from_bip340_test_vectors() {
+        for (i, test_vector) in bip340_test_vectors::test_vectors().into_iter().enumerate() {
+            let Some(private_key) = test_vector.seckey else {
+                continue;
+            };
+            let Some(aux_random) = test_vector.aux_rand else {
+                continue;
+            };
+            let Some(message) = test_vector.message else {
+                continue;
+            };
+            if !test_vector.verification_result {
+                continue;
+            }
+            let expected_signature = &test_vector.signature;
+
+            let signature = Signature::new_with_aux_random(&private_key, &message, aux_random);
+
+            assert_eq!(&signature, expected_signature, "Failed test vector {i}");
+        }
+    }
+
+    #[test]
+    fn signature_verification_from_bip340_test_vectors() {
+        for (i, test_vector) in bip340_test_vectors::test_vectors().into_iter().enumerate() {
+            let message = test_vector.message.unwrap_or(vec![]);
+            let expected_result = test_vector.verification_result;
+
+            let result = test_vector
+                .signature
+                .is_valid_for(&message, &test_vector.pubkey);
+
+            assert_eq!(result, expected_result, "Failed test vector {i}");
+        }
+    }
+}
diff --git a/nssa/core/src/signature/private_key.rs b/nssa/core/src/signature/private_key.rs
new file mode 100644
index 00000000..d5a43042
--- /dev/null
+++ b/nssa/core/src/signature/private_key.rs
@@ -0,0 +1,78 @@
+use std::str::FromStr;
+
+use rand::{Rng as _, rngs::OsRng};
+use serde_with::{DeserializeFromStr, SerializeDisplay};
+
+use crate::error::NssaCoreError;
+
+// TODO: Remove Debug, Clone, Serialize, Deserialize, PartialEq and Eq for security reasons
+// TODO: Implement Zeroize
+#[derive(Clone, SerializeDisplay, DeserializeFromStr, PartialEq, Eq)]
+pub struct PrivateKey([u8; 32]);
+
+impl std::fmt::Debug for PrivateKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
+    }
+}
+
+impl std::fmt::Display for PrivateKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", hex::encode(self.0))
+    }
+}
+
+impl FromStr for PrivateKey {
+    type Err = NssaCoreError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut bytes = [0_u8; 32];
+        hex::decode_to_slice(s, &mut bytes).map_err(|_err| NssaCoreError::InvalidPrivateKey)?;
+        Self::try_new(bytes)
+    }
+}
+
+impl PrivateKey {
+    #[must_use]
+    pub fn new_os_random() -> Self {
+        let mut rng = OsRng;
+
+        loop {
+            if let Ok(key) = Self::try_new(rng.r#gen()) {
+                break key;
+            }
+        }
+    }
+
+    fn is_valid_key(value: [u8; 32]) -> bool {
+        k256::SecretKey::from_bytes(&value.into()).is_ok()
+    }
+
+    pub fn try_new(value: [u8; 32]) -> Result<Self, NssaCoreError> {
+        if Self::is_valid_key(value) {
+            Ok(Self(value))
+        } else {
+            Err(NssaCoreError::InvalidPrivateKey)
+        }
+    }
+
+    #[must_use]
+    pub const fn value(&self) -> &[u8; 32] {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn value_getter() {
+        let key = PrivateKey::try_new([1; 32]).unwrap();
+        assert_eq!(key.value(), &key.0);
+    }
+
+    #[test]
+    fn produce_key() {
+        let _key = PrivateKey::new_os_random();
+    }
+}
diff --git a/nssa/core/src/signature/public_key.rs b/nssa/core/src/signature/public_key.rs
new file mode 100644
index 00000000..489b8d48
--- /dev/null
+++ b/nssa/core/src/signature/public_key.rs
@@ -0,0 +1,135 @@
+use std::str::FromStr;
+
+use borsh::{BorshDeserialize, BorshSerialize};
+use k256::elliptic_curve::sec1::ToEncodedPoint as _;
+use serde_with::{DeserializeFromStr, SerializeDisplay};
+
+use crate::{PrivateKey, error::NssaCoreError};
+
+#[derive(Clone, PartialEq, Eq, BorshSerialize, SerializeDisplay, DeserializeFromStr)]
+pub struct PublicKey([u8; 32]);
+
+impl std::fmt::Debug for PublicKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self, f)
+    }
+}
+
+impl std::fmt::Display for PublicKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", hex::encode(self.0))
+    }
+}
+
+impl FromStr for PublicKey {
+    type Err = NssaCoreError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut bytes = [0_u8; 32];
+        hex::decode_to_slice(s, &mut bytes).map_err(NssaCoreError::InvalidHexPublicKey)?;
+        Self::try_new(bytes)
+    }
+}
+
+impl BorshDeserialize for PublicKey {
+    fn deserialize_reader<R: std::io::Read>(reader: &mut R) -> std::io::Result<Self> {
+        let mut buf = [0_u8; 32];
+        reader.read_exact(&mut buf)?;
+
+        Self::try_new(buf).map_err(|err| std::io::Error::new(std::io::ErrorKind::InvalidData, err))
+    }
+}
+
+impl PublicKey {
+    #[must_use]
+    pub fn new_from_private_key(key: &PrivateKey) -> Self {
+        let value = {
+            let secret_key = k256::SecretKey::from_bytes(&(*key.value()).into())
+                .expect("Expect a valid private key");
+
+            let encoded = secret_key.public_key().to_encoded_point(false);
+            let x_only = encoded
+                .x()
+                .expect("Expect k256 point to have a x-coordinate");
+
+            *x_only.first_chunk().expect("x_only is exactly 32 bytes")
+        };
+        Self(value)
+    }
+
+    pub fn try_new(value: [u8; 32]) -> Result<Self, NssaCoreError> {
+        // Check point is a valid x-only public key
+        let _ = k256::schnorr::VerifyingKey::from_bytes(&value)
+            .map_err(NssaCoreError::InvalidPublicKey)?;
+
+        Ok(Self(value))
+    }
+
+    #[must_use]
+    pub const fn value(&self) -> &[u8; 32] {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{PublicKey, error::NssaCoreError, signature::bip340_test_vectors};
+
+    #[test]
+    fn try_new_invalid_public_key_from_bip340_test_vectors_5() {
+        let value_invalid_key = [
+            238, 253, 234, 76, 219, 103, 119, 80, 164, 32, 254, 232, 7, 234, 207, 33, 235, 152,
+            152, 174, 121, 185, 118, 135, 102, 228, 250, 160, 74, 45, 74, 52,
+        ];
+
+        let result = PublicKey::try_new(value_invalid_key);
+
+        assert!(matches!(result, Err(NssaCoreError::InvalidPublicKey(_))));
+    }
+
+    #[test]
+    fn try_new_invalid_public_key_from_bip340_test_vector_14() {
+        let value_invalid_key = [
+            255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+            255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 254, 255, 255, 252, 48,
+        ];
+
+        let result = PublicKey::try_new(value_invalid_key);
+
+        assert!(matches!(result, Err(NssaCoreError::InvalidPublicKey(_))));
+    }
+
+    #[test]
+    fn try_new_valid_public_keys() {
+        for (i, test_vector) in bip340_test_vectors::test_vectors().into_iter().enumerate() {
+            let expected_public_key = test_vector.pubkey;
+            let public_key = PublicKey::try_new(*expected_public_key.value()).unwrap();
+            assert_eq!(public_key, expected_public_key, "Failed on test vector {i}");
+        }
+    }
+
+    #[test]
+    fn public_key_generation_from_bip340_test_vectors() {
+        for (i, test_vector) in bip340_test_vectors::test_vectors().into_iter().enumerate() {
+            let Some(private_key) = &test_vector.seckey else {
+                continue;
+            };
+            let public_key = PublicKey::new_from_private_key(private_key);
+            let expected_public_key = &test_vector.pubkey;
+            assert_eq!(
+                &public_key, expected_public_key,
+                "Failed test vector at index {i}"
+            );
+        }
+    }
+
+    #[test]
+    fn correct_ser_deser_roundtrip() {
+        let pub_key = PublicKey::try_new([42; 32]).unwrap();
+
+        let pub_key_borsh_ser = borsh::to_vec(&pub_key).unwrap();
+        let pub_key_new: PublicKey = borsh::from_slice(&pub_key_borsh_ser).unwrap();
+
+        assert_eq!(pub_key, pub_key_new);
+    }
+}
diff --git a/nssa/src/error.rs b/nssa/src/error.rs
index 61966515..a5210901 100644
--- a/nssa/src/error.rs
+++ b/nssa/src/error.rs
@@ -22,18 +22,9 @@ pub enum NssaError {
     #[error("Serialization error: {0}")]
     InstructionSerializationError(String),
 
-    #[error("Invalid private key")]
-    InvalidPrivateKey,
-
     #[error("IO error: {0}")]
     Io(#[from] io::Error),
 
-    #[error("Invalid Public Key")]
-    InvalidPublicKey(#[source] k256::schnorr::Error),
-
-    #[error("Invalid hex for public key")]
-    InvalidHexPublicKey(hex::FromHexError),
-
     #[error("Risc0 error: {0}")]
     ProgramWriteInputFailed(String),
 
diff --git a/nssa/src/lib.rs b/nssa/src/lib.rs
index f4c3be9d..b3c440c7 100644
--- a/nssa/src/lib.rs
+++ b/nssa/src/lib.rs
@@ -15,7 +15,6 @@ pub use privacy_preserving_transaction::{
 pub use program_deployment_transaction::ProgramDeploymentTransaction;
 pub use program_methods::PRIVACY_PRESERVING_CIRCUIT_ID;
 pub use public_transaction::PublicTransaction;
-pub use signature::{PrivateKey, PublicKey, Signature};
 pub use state::{
     CLOCK_01_PROGRAM_ACCOUNT_ID, CLOCK_10_PROGRAM_ACCOUNT_ID, CLOCK_50_PROGRAM_ACCOUNT_ID,
     CLOCK_PROGRAM_ACCOUNT_IDS, V03State,
@@ -29,7 +28,6 @@ pub mod privacy_preserving_transaction;
 pub mod program;
 pub mod program_deployment_transaction;
 pub mod public_transaction;
-mod signature;
 mod state;
 mod validated_state_diff;
 
diff --git a/nssa/src/privacy_preserving_transaction/circuit.rs b/nssa/src/privacy_preserving_transaction/circuit.rs
index 6c174450..92ce2e33 100644
--- a/nssa/src/privacy_preserving_transaction/circuit.rs
+++ b/nssa/src/privacy_preserving_transaction/circuit.rs
@@ -4,7 +4,7 @@ use borsh::{BorshDeserialize, BorshSerialize};
 use nssa_core::{
     MembershipProof, NullifierPublicKey, NullifierSecretKey, PrivacyPreservingCircuitInput,
     PrivacyPreservingCircuitOutput, SharedSecretKey,
-    account::AccountWithMetadata,
+    account::{AccountWithMetadata, Identifier},
     program::{ChainedCall, InstructionData, ProgramId, ProgramOutput},
 };
 use risc0_zkvm::{ExecutorEnv, InnerReceipt, ProverOpts, Receipt, default_prover};
@@ -63,13 +63,14 @@ impl From<Program> for ProgramWithDependencies {
 
 /// Generates a proof of the execution of a NSSA program inside the privacy preserving execution
 /// circuit.
-/// TODO: too many parameters.
+#[expect(clippy::too_many_arguments, reason = "TODO: fix this later")]
 pub fn execute_and_prove(
     pre_states: Vec<AccountWithMetadata>,
     instruction_data: InstructionData,
     visibility_mask: Vec<u8>,
     private_account_keys: Vec<(NullifierPublicKey, SharedSecretKey)>,
     private_account_nsks: Vec<NullifierSecretKey>,
+    private_account_identifiers: Vec<Identifier>,
     private_account_membership_proofs: Vec<Option<MembershipProof>>,
     program_with_dependencies: &ProgramWithDependencies,
 ) -> Result<(PrivacyPreservingCircuitOutput, Proof), NssaError> {
@@ -129,6 +130,7 @@ pub fn execute_and_prove(
         visibility_mask,
         private_account_keys,
         private_account_nsks,
+        private_account_identifiers,
         private_account_membership_proofs,
         program_id: program_with_dependencies.program.id(),
     };
@@ -183,7 +185,7 @@ mod tests {
 
     use nssa_core::{
         Commitment, DUMMY_COMMITMENT_HASH, EncryptionScheme, Nullifier, SharedSecretKey,
-        account::{Account, AccountId, AccountWithMetadata, Nonce, data::Data},
+        account::{Account, AccountId, AccountWithMetadata, Identifier, Nonce, data::Data},
     };
 
     use super::*;
@@ -214,7 +216,7 @@ mod tests {
         let recipient = AccountWithMetadata::new(
             Account::default(),
             false,
-            AccountId::from(&recipient_keys.npk()),
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier),
         );
 
         let balance_to_move: u128 = 37;
@@ -244,6 +246,7 @@ mod tests {
             vec![0, 2],
             vec![(recipient_keys.npk(), shared_secret)],
             vec![],
+            vec![recipient_keys.identifier],
             vec![None],
             &Program::authenticated_transfer_program().into(),
         )
@@ -274,6 +277,8 @@ mod tests {
         let program = Program::authenticated_transfer_program();
         let sender_keys = test_private_account_keys_1();
         let recipient_keys = test_private_account_keys_2();
+        let recipient_id =
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier);
 
         let sender_nonce = Nonce(0xdead_beef);
         let sender_pre = AccountWithMetadata::new(
@@ -284,14 +289,14 @@ mod tests {
                 data: Data::default(),
             },
             true,
-            AccountId::from(&sender_keys.npk()),
+            AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier),
         );
-        let commitment_sender = Commitment::new(&sender_keys.npk(), &sender_pre.account);
+        let commitment_sender = Commitment::new(&sender_pre.account_id, &sender_pre.account);
 
         let recipient = AccountWithMetadata::new(
             Account::default(),
             false,
-            AccountId::from(&recipient_keys.npk()),
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier),
         );
         let balance_to_move: u128 = 37;
 
@@ -304,7 +309,7 @@ mod tests {
                 commitment_set.digest(),
             ),
             (
-                Nullifier::for_account_initialization(&recipient_keys.npk()),
+                Nullifier::for_account_initialization(&recipient_id),
                 DUMMY_COMMITMENT_HASH,
             ),
         ];
@@ -324,8 +329,8 @@ mod tests {
             ..Default::default()
         };
         let expected_new_commitments = vec![
-            Commitment::new(&sender_keys.npk(), &expected_private_account_1),
-            Commitment::new(&recipient_keys.npk(), &expected_private_account_2),
+            Commitment::new(&sender_pre.account_id, &expected_private_account_1),
+            Commitment::new(&recipient.account_id, &expected_private_account_2),
         ];
 
         let esk_1 = [3; 32];
@@ -343,6 +348,7 @@ mod tests {
                 (recipient_keys.npk(), shared_secret_2),
             ],
             vec![sender_keys.nsk],
+            vec![sender_keys.identifier, recipient_keys.identifier],
             vec![commitment_set.get_proof_for(&commitment_sender), None],
             &program.into(),
         )
@@ -380,7 +386,7 @@ mod tests {
         let pre = AccountWithMetadata::new(
             Account::default(),
             false,
-            AccountId::from(&account_keys.npk()),
+            AccountId::private_account_id(&account_keys.npk(), Identifier(42_u128)),
         );
 
         let validity_window_chain_caller = Program::validity_window_chain_caller();
@@ -409,6 +415,7 @@ mod tests {
             vec![2],
             vec![(account_keys.npk(), shared_secret)],
             vec![],
+            vec![Identifier(42_u128)],
             vec![None],
             &program_with_deps,
         );
diff --git a/nssa/src/privacy_preserving_transaction/message.rs b/nssa/src/privacy_preserving_transaction/message.rs
index 85f4a202..601835ad 100644
--- a/nssa/src/privacy_preserving_transaction/message.rs
+++ b/nssa/src/privacy_preserving_transaction/message.rs
@@ -1,6 +1,6 @@
 use borsh::{BorshDeserialize, BorshSerialize};
 use nssa_core::{
-    Commitment, CommitmentSetDigest, Nullifier, NullifierPublicKey, PrivacyPreservingCircuitOutput,
+    Commitment, CommitmentSetDigest, Nullifier, PrivacyPreservingCircuitOutput,
     account::{Account, Nonce},
     encryption::{Ciphertext, EphemeralPublicKey, ViewingPublicKey},
     program::{BlockValidityWindow, TimestampValidityWindow},
@@ -21,11 +21,11 @@ pub struct EncryptedAccountData {
 impl EncryptedAccountData {
     fn new(
         ciphertext: Ciphertext,
-        npk: &NullifierPublicKey,
+        account_id: &AccountId,
         vpk: &ViewingPublicKey,
         epk: EphemeralPublicKey,
     ) -> Self {
-        let view_tag = Self::compute_view_tag(npk, vpk);
+        let view_tag = Self::compute_view_tag(account_id, vpk);
         Self {
             ciphertext,
             epk,
@@ -35,10 +35,13 @@ impl EncryptedAccountData {
 
     /// Computes the tag as the first byte of SHA256("/LEE/v0.3/ViewTag/" || Npk || vpk).
     #[must_use]
-    pub fn compute_view_tag(npk: &NullifierPublicKey, vpk: &ViewingPublicKey) -> ViewTag {
+    pub fn compute_view_tag(account_id: &AccountId, vpk: &ViewingPublicKey) -> ViewTag {
+        const VIEWTAG_PREFIX: &[u8; 32] =
+            b"/LEE/v0.3/ViewTag\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
+
         let mut hasher = Sha256::new();
-        hasher.update(b"/LEE/v0.3/ViewTag/");
-        hasher.update(npk.to_byte_array());
+        hasher.update(VIEWTAG_PREFIX);
+        hasher.update(account_id.to_bytes());
         hasher.update(vpk.to_bytes());
         let digest: [u8; 32] = hasher.finalize().into();
         digest[0]
@@ -90,7 +93,10 @@ impl Message {
     pub fn try_from_circuit_output(
         public_account_ids: Vec<AccountId>,
         nonces: Vec<Nonce>,
-        public_keys: Vec<(NullifierPublicKey, ViewingPublicKey, EphemeralPublicKey)>,
+        public_keys: Vec<(AccountId, ViewingPublicKey, EphemeralPublicKey)>, /* TODO: Rename
+                                                                              * `public_keys` to
+                                                                              * account for
+                                                                              * `account_id`. */
         output: PrivacyPreservingCircuitOutput,
     ) -> Result<Self, NssaError> {
         if public_keys.len() != output.ciphertexts.len() {
@@ -103,8 +109,8 @@ impl Message {
             .ciphertexts
             .into_iter()
             .zip(public_keys)
-            .map(|(ciphertext, (npk, vpk, epk))| {
-                EncryptedAccountData::new(ciphertext, &npk, &vpk, epk)
+            .map(|(ciphertext, (account_id, vpk, epk))| {
+                EncryptedAccountData::new(ciphertext, &account_id, &vpk, epk)
             })
             .collect();
         Ok(Self {
@@ -124,7 +130,7 @@ impl Message {
 pub mod tests {
     use nssa_core::{
         Commitment, EncryptionScheme, Nullifier, NullifierPublicKey, SharedSecretKey,
-        account::Account,
+        account::{Account, Identifier},
         encryption::{EphemeralPublicKey, ViewingPublicKey},
         program::{BlockValidityWindow, TimestampValidityWindow},
     };
@@ -146,7 +152,9 @@ pub mod tests {
         let npk1 = NullifierPublicKey::from(&nsk1);
         let npk2 = NullifierPublicKey::from(&nsk2);
 
-        let public_account_ids = vec![AccountId::new([1; 32])];
+        let account_id1 = AccountId::private_account_id(&npk1, Identifier(0_u128));
+        let account_id2 = AccountId::private_account_id(&npk2, Identifier(0_u128));
+        let public_account_ids = vec![account_id1, account_id2];
 
         let nonces = vec![1_u128.into(), 2_u128.into(), 3_u128.into()];
 
@@ -154,9 +162,9 @@ pub mod tests {
 
         let encrypted_private_post_states = Vec::new();
 
-        let new_commitments = vec![Commitment::new(&npk2, &account2)];
+        let new_commitments = vec![Commitment::new(&account_id2, &account2)];
 
-        let old_commitment = Commitment::new(&npk1, &account1);
+        let old_commitment = Commitment::new(&account_id1, &account1);
         let new_nullifiers = vec![(
             Nullifier::for_account_update(&old_commitment, &nsk1),
             [0; 32],
@@ -178,19 +186,22 @@ pub mod tests {
     fn encrypted_account_data_constructor() {
         let npk = NullifierPublicKey::from(&[1; 32]);
         let vpk = ViewingPublicKey::from_scalar([2; 32]);
+        let account_id = AccountId::private_account_id(&npk, Identifier(0_u128));
         let account = Account::default();
-        let commitment = Commitment::new(&npk, &account);
+        let commitment = Commitment::new(&account_id, &account);
         let esk = [3; 32];
         let shared_secret = SharedSecretKey::new(&esk, &vpk);
         let epk = EphemeralPublicKey::from_scalar(esk);
         let ciphertext = EncryptionScheme::encrypt(&account, &shared_secret, &commitment, 2);
         let encrypted_account_data =
-            EncryptedAccountData::new(ciphertext.clone(), &npk, &vpk, epk.clone());
+            EncryptedAccountData::new(ciphertext.clone(), &account_id, &vpk, epk.clone());
 
         let expected_view_tag = {
             let mut hasher = Sha256::new();
-            hasher.update(b"/LEE/v0.3/ViewTag/");
-            hasher.update(npk.to_byte_array());
+            hasher.update(
+                b"/LEE/v0.3/ViewTag\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
+            );
+            hasher.update(account_id.to_bytes());
             hasher.update(vpk.to_bytes());
             let digest: [u8; 32] = hasher.finalize().into();
             digest[0]
@@ -200,7 +211,7 @@ pub mod tests {
         assert_eq!(encrypted_account_data.epk, epk);
         assert_eq!(
             encrypted_account_data.view_tag,
-            EncryptedAccountData::compute_view_tag(&npk, &vpk)
+            EncryptedAccountData::compute_view_tag(&account_id, &vpk)
         );
         assert_eq!(encrypted_account_data.view_tag, expected_view_tag);
     }
diff --git a/nssa/src/privacy_preserving_transaction/transaction.rs b/nssa/src/privacy_preserving_transaction/transaction.rs
index 2e46f628..9eff3d64 100644
--- a/nssa/src/privacy_preserving_transaction/transaction.rs
+++ b/nssa/src/privacy_preserving_transaction/transaction.rs
@@ -43,7 +43,7 @@ impl PrivacyPreservingTransaction {
         self.witness_set
             .signatures_and_public_keys()
             .iter()
-            .map(|(_, public_key)| AccountId::from(public_key))
+            .map(|(_, public_key)| AccountId::public_account_id(public_key))
             .collect()
     }
 
@@ -61,8 +61,10 @@ impl PrivacyPreservingTransaction {
 
 #[cfg(test)]
 mod tests {
+    use nssa_core::{PrivateKey, PublicKey};
+
     use crate::{
-        AccountId, PrivacyPreservingTransaction, PrivateKey, PublicKey,
+        AccountId, PrivacyPreservingTransaction,
         privacy_preserving_transaction::{
             circuit::Proof, message::tests::message_for_tests, witness_set::WitnessSet,
         },
@@ -71,8 +73,8 @@ mod tests {
     fn keys_for_tests() -> (PrivateKey, PrivateKey, AccountId, AccountId) {
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let addr1 = AccountId::from(&PublicKey::new_from_private_key(&key1));
-        let addr2 = AccountId::from(&PublicKey::new_from_private_key(&key2));
+        let addr1 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
+        let addr2 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key2));
         (key1, key2, addr1, addr2)
     }
 
diff --git a/nssa/src/privacy_preserving_transaction/witness_set.rs b/nssa/src/privacy_preserving_transaction/witness_set.rs
index 373bbc9c..9b3a8eaa 100644
--- a/nssa/src/privacy_preserving_transaction/witness_set.rs
+++ b/nssa/src/privacy_preserving_transaction/witness_set.rs
@@ -1,9 +1,7 @@
 use borsh::{BorshDeserialize, BorshSerialize};
+use nssa_core::{PrivateKey, PublicKey, Signature};
 
-use crate::{
-    PrivateKey, PublicKey, Signature,
-    privacy_preserving_transaction::{circuit::Proof, message::Message},
-};
+use crate::privacy_preserving_transaction::{circuit::Proof, message::Message};
 
 #[derive(Debug, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
 pub struct WitnessSet {
diff --git a/nssa/src/public_transaction/transaction.rs b/nssa/src/public_transaction/transaction.rs
index 5ab87fa1..69dd107c 100644
--- a/nssa/src/public_transaction/transaction.rs
+++ b/nssa/src/public_transaction/transaction.rs
@@ -35,7 +35,7 @@ impl PublicTransaction {
         self.witness_set
             .signatures_and_public_keys()
             .iter()
-            .map(|(_, public_key)| AccountId::from(public_key))
+            .map(|(_, public_key)| AccountId::public_account_id(public_key))
             .collect()
     }
 
@@ -61,10 +61,11 @@ impl PublicTransaction {
 
 #[cfg(test)]
 pub mod tests {
+    use nssa_core::{PrivateKey, PublicKey};
     use sha2::{Digest as _, digest::FixedOutput as _};
 
     use crate::{
-        AccountId, PrivateKey, PublicKey, PublicTransaction, Signature, V03State,
+        AccountId, PublicTransaction, V03State,
         error::NssaError,
         program::Program,
         public_transaction::{Message, WitnessSet},
@@ -74,8 +75,8 @@ pub mod tests {
     fn keys_for_tests() -> (PrivateKey, PrivateKey, AccountId, AccountId) {
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let addr1 = AccountId::from(&PublicKey::new_from_private_key(&key1));
-        let addr2 = AccountId::from(&PublicKey::new_from_private_key(&key2));
+        let addr1 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
+        let addr2 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key2));
         (key1, key2, addr1, addr2)
     }
 
@@ -201,8 +202,11 @@ pub mod tests {
         assert!(matches!(result, Err(NssaError::InvalidInput(_))));
     }
 
+    #[cfg(feature = "test-utils")]
     #[test]
     fn all_signatures_must_be_valid() {
+        use nssa_core::Signature;
+
         let (key1, key2, addr1, addr2) = keys_for_tests();
         let state = state_for_tests();
         let nonces = vec![0_u128.into(), 0_u128.into()];
diff --git a/nssa/src/public_transaction/witness_set.rs b/nssa/src/public_transaction/witness_set.rs
index d6b32891..e22af371 100644
--- a/nssa/src/public_transaction/witness_set.rs
+++ b/nssa/src/public_transaction/witness_set.rs
@@ -1,6 +1,7 @@
 use borsh::{BorshDeserialize, BorshSerialize};
+use nssa_core::{PrivateKey, PublicKey, Signature};
 
-use crate::{PrivateKey, PublicKey, Signature, public_transaction::Message};
+use crate::public_transaction::Message;
 
 #[derive(Debug, Clone, PartialEq, Eq, BorshSerialize, BorshDeserialize)]
 pub struct WitnessSet {
@@ -65,8 +66,8 @@ mod tests {
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
         let pubkey1 = PublicKey::new_from_private_key(&key1);
         let pubkey2 = PublicKey::new_from_private_key(&key2);
-        let addr1 = AccountId::from(&pubkey1);
-        let addr2 = AccountId::from(&pubkey2);
+        let addr1 = AccountId::public_account_id(&pubkey1);
+        let addr2 = AccountId::public_account_id(&pubkey2);
         let nonces = vec![1_u128.into(), 2_u128.into()];
         let instruction = vec![1, 2, 3, 4];
         let message = Message::try_new([0; 8], vec![addr1, addr2], nonces, instruction).unwrap();
diff --git a/nssa/src/state.rs b/nssa/src/state.rs
index 7753e1a3..1e8bb6ce 100644
--- a/nssa/src/state.rs
+++ b/nssa/src/state.rs
@@ -357,15 +357,15 @@ pub mod tests {
     use std::collections::HashMap;
 
     use nssa_core::{
-        BlockId, Commitment, Nullifier, NullifierPublicKey, NullifierSecretKey, SharedSecretKey,
-        Timestamp,
-        account::{Account, AccountId, AccountWithMetadata, Nonce, data::Data},
+        BlockId, Commitment, Nullifier, NullifierPublicKey, NullifierSecretKey, PrivateKey,
+        PublicKey, SharedSecretKey, Timestamp,
+        account::{Account, AccountId, AccountWithMetadata, Identifier, Nonce, data::Data},
         encryption::{EphemeralPublicKey, Scalar, ViewingPublicKey},
         program::{BlockValidityWindow, PdaSeed, ProgramId, TimestampValidityWindow},
     };
 
     use crate::{
-        PublicKey, PublicTransaction, V03State,
+        PublicTransaction, V03State,
         error::NssaError,
         execute_and_prove,
         privacy_preserving_transaction::{
@@ -376,7 +376,6 @@ pub mod tests {
         },
         program::Program,
         public_transaction,
-        signature::PrivateKey,
         state::{
             CLOCK_01_PROGRAM_ACCOUNT_ID, CLOCK_10_PROGRAM_ACCOUNT_ID, CLOCK_50_PROGRAM_ACCOUNT_ID,
             CLOCK_PROGRAM_ACCOUNT_IDS, MAX_NUMBER_CHAINED_CALLS,
@@ -451,7 +450,8 @@ pub mod tests {
 
         #[must_use]
         pub fn with_private_account(mut self, keys: &TestPrivateKeys, account: &Account) -> Self {
-            let commitment = Commitment::new(&keys.npk(), account);
+            let account_id = &AccountId::private_account_id(&keys.npk(), keys.identifier);
+            let commitment = Commitment::new(account_id, account);
             self.private_state.0.extend(&[commitment]);
             self
         }
@@ -463,13 +463,14 @@ pub mod tests {
 
     impl TestPublicKeys {
         pub fn account_id(&self) -> AccountId {
-            AccountId::from(&PublicKey::new_from_private_key(&self.signing_key))
+            AccountId::public_account_id(&PublicKey::new_from_private_key(&self.signing_key))
         }
     }
 
     pub struct TestPrivateKeys {
         pub nsk: NullifierSecretKey,
         pub vsk: Scalar,
+        pub identifier: Identifier,
     }
 
     impl TestPrivateKeys {
@@ -544,8 +545,8 @@ pub mod tests {
     fn new_with_genesis() {
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let addr1 = AccountId::from(&PublicKey::new_from_private_key(&key1));
-        let addr2 = AccountId::from(&PublicKey::new_from_private_key(&key2));
+        let addr1 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
+        let addr2 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key2));
         let initial_data = [(addr1, 100_u128), (addr2, 151_u128)];
         let authenticated_transfers_program = Program::authenticated_transfer_program();
         let clock_program = Program::clock();
@@ -613,7 +614,7 @@ pub mod tests {
     #[test]
     fn get_account_by_account_id_non_default_account() {
         let key = PrivateKey::try_new([1; 32]).unwrap();
-        let account_id = AccountId::from(&PublicKey::new_from_private_key(&key));
+        let account_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&key));
         let initial_data = [(account_id, 100_u128)];
         let state = V03State::new_with_genesis_accounts(&initial_data, &[], 0);
         let expected_account = &state.public_state[&account_id];
@@ -646,12 +647,12 @@ pub mod tests {
     #[test]
     fn transition_from_authenticated_transfer_program_invocation_default_account_destination() {
         let key = PrivateKey::try_new([1; 32]).unwrap();
-        let account_id = AccountId::from(&PublicKey::new_from_private_key(&key));
+        let account_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&key));
         let initial_data = [(account_id, 100)];
         let mut state = V03State::new_with_genesis_accounts(&initial_data, &[], 0);
         let from = account_id;
         let to_key = PrivateKey::try_new([2; 32]).unwrap();
-        let to = AccountId::from(&PublicKey::new_from_private_key(&to_key));
+        let to = AccountId::public_account_id(&PublicKey::new_from_private_key(&to_key));
         assert_eq!(state.get_account_by_id(to), Account::default());
         let balance_to_move = 5;
 
@@ -667,13 +668,13 @@ pub mod tests {
     #[test]
     fn transition_from_authenticated_transfer_program_invocation_insuficient_balance() {
         let key = PrivateKey::try_new([1; 32]).unwrap();
-        let account_id = AccountId::from(&PublicKey::new_from_private_key(&key));
+        let account_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&key));
         let initial_data = [(account_id, 100)];
         let mut state = V03State::new_with_genesis_accounts(&initial_data, &[], 0);
         let from = account_id;
         let from_key = key;
         let to_key = PrivateKey::try_new([2; 32]).unwrap();
-        let to = AccountId::from(&PublicKey::new_from_private_key(&to_key));
+        let to = AccountId::public_account_id(&PublicKey::new_from_private_key(&to_key));
         let balance_to_move = 101;
         assert!(state.get_account_by_id(from).balance < balance_to_move);
 
@@ -691,8 +692,8 @@ pub mod tests {
     fn transition_from_authenticated_transfer_program_invocation_non_default_account_destination() {
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let account_id1 = AccountId::from(&PublicKey::new_from_private_key(&key1));
-        let account_id2 = AccountId::from(&PublicKey::new_from_private_key(&key2));
+        let account_id1 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
+        let account_id2 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key2));
         let initial_data = [(account_id1, 100), (account_id2, 200)];
         let mut state = V03State::new_with_genesis_accounts(&initial_data, &[], 0);
         let from = account_id2;
@@ -714,13 +715,13 @@ pub mod tests {
     #[test]
     fn transition_from_sequence_of_authenticated_transfer_program_invocations() {
         let key1 = PrivateKey::try_new([8; 32]).unwrap();
-        let account_id1 = AccountId::from(&PublicKey::new_from_private_key(&key1));
+        let account_id1 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
         let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let account_id2 = AccountId::from(&PublicKey::new_from_private_key(&key2));
+        let account_id2 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key2));
         let initial_data = [(account_id1, 100)];
         let mut state = V03State::new_with_genesis_accounts(&initial_data, &[], 0);
         let key3 = PrivateKey::try_new([3; 32]).unwrap();
-        let account_id3 = AccountId::from(&PublicKey::new_from_private_key(&key3));
+        let account_id3 = AccountId::public_account_id(&PublicKey::new_from_private_key(&key3));
         let balance_to_move = 5;
 
         let tx = transfer_transaction(
@@ -1153,6 +1154,7 @@ pub mod tests {
         TestPrivateKeys {
             nsk: [13; 32],
             vsk: [31; 32],
+            identifier: Identifier(12_u128),
         }
     }
 
@@ -1160,6 +1162,7 @@ pub mod tests {
         TestPrivateKeys {
             nsk: [38; 32],
             vsk: [83; 32],
+            identifier: Identifier(42_u128),
         }
     }
 
@@ -1177,7 +1180,9 @@ pub mod tests {
 
         let sender_nonce = sender.account.nonce;
 
-        let recipient = AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+        let recipient_id =
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier);
+        let recipient = AccountWithMetadata::new(Account::default(), false, recipient_id);
 
         let esk = [3; 32];
         let shared_secret = SharedSecretKey::new(&esk, &recipient_keys.vpk());
@@ -1189,6 +1194,7 @@ pub mod tests {
             vec![0, 2],
             vec![(recipient_keys.npk(), shared_secret)],
             vec![],
+            vec![recipient_keys.identifier],
             vec![None],
             &Program::authenticated_transfer_program().into(),
         )
@@ -1197,7 +1203,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![sender_keys.account_id()],
             vec![sender_nonce],
-            vec![(recipient_keys.npk(), recipient_keys.vpk(), epk)],
+            vec![(recipient_id, recipient_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -1214,11 +1220,12 @@ pub mod tests {
         state: &V03State,
     ) -> PrivacyPreservingTransaction {
         let program = Program::authenticated_transfer_program();
-        let sender_commitment = Commitment::new(&sender_keys.npk(), sender_private_account);
-        let sender_pre =
-            AccountWithMetadata::new(sender_private_account.clone(), true, &sender_keys.npk());
-        let recipient_pre =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
+        let recipient_id =
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier);
+        let sender_commitment = Commitment::new(&sender_id, sender_private_account);
+        let sender_pre = AccountWithMetadata::new(sender_private_account.clone(), true, sender_id);
+        let recipient_pre = AccountWithMetadata::new(Account::default(), false, recipient_id);
 
         let esk_1 = [3; 32];
         let shared_secret_1 = SharedSecretKey::new(&esk_1, &sender_keys.vpk());
@@ -1237,6 +1244,7 @@ pub mod tests {
                 (recipient_keys.npk(), shared_secret_2),
             ],
             vec![sender_keys.nsk],
+            vec![sender_keys.identifier, recipient_keys.identifier],
             vec![state.get_proof_for_commitment(&sender_commitment), None],
             &program.into(),
         )
@@ -1246,8 +1254,8 @@ pub mod tests {
             vec![],
             vec![],
             vec![
-                (sender_keys.npk(), sender_keys.vpk(), epk_1),
-                (recipient_keys.npk(), recipient_keys.vpk(), epk_2),
+                (sender_id, sender_keys.vpk(), epk_1),
+                (recipient_id, recipient_keys.vpk(), epk_2),
             ],
             output,
         )
@@ -1266,9 +1274,9 @@ pub mod tests {
         state: &V03State,
     ) -> PrivacyPreservingTransaction {
         let program = Program::authenticated_transfer_program();
-        let sender_commitment = Commitment::new(&sender_keys.npk(), sender_private_account);
-        let sender_pre =
-            AccountWithMetadata::new(sender_private_account.clone(), true, &sender_keys.npk());
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
+        let sender_commitment = Commitment::new(&sender_id, sender_private_account);
+        let sender_pre = AccountWithMetadata::new(sender_private_account.clone(), true, sender_id);
         let recipient_pre = AccountWithMetadata::new(
             state.get_account_by_id(*recipient_account_id),
             false,
@@ -1285,6 +1293,7 @@ pub mod tests {
             vec![1, 0],
             vec![(sender_keys.npk(), shared_secret)],
             vec![sender_keys.nsk],
+            vec![sender_keys.identifier],
             vec![state.get_proof_for_commitment(&sender_commitment)],
             &program.into(),
         )
@@ -1293,7 +1302,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![*recipient_account_id],
             vec![],
-            vec![(sender_keys.npk(), sender_keys.vpk(), epk)],
+            vec![(sender_id, sender_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -1370,8 +1379,12 @@ pub mod tests {
             &state,
         );
 
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
+        let recipient_id =
+            AccountId::private_account_id(&recipient_keys.npk(), recipient_keys.identifier);
+
         let expected_new_commitment_1 = Commitment::new(
-            &sender_keys.npk(),
+            &sender_id,
             &Account {
                 program_owner: Program::authenticated_transfer_program().id(),
                 nonce: sender_nonce.private_account_nonce_increment(&sender_keys.nsk),
@@ -1380,12 +1393,12 @@ pub mod tests {
             },
         );
 
-        let sender_pre_commitment = Commitment::new(&sender_keys.npk(), &sender_private_account);
+        let sender_pre_commitment = Commitment::new(&sender_id, &sender_private_account);
         let expected_new_nullifier =
             Nullifier::for_account_update(&sender_pre_commitment, &sender_keys.nsk);
 
         let expected_new_commitment_2 = Commitment::new(
-            &recipient_keys.npk(),
+            &recipient_id,
             &Account {
                 program_owner: Program::authenticated_transfer_program().id(),
                 nonce: Nonce::private_account_nonce_init(&recipient_keys.npk()),
@@ -1414,6 +1427,7 @@ pub mod tests {
     #[test]
     fn transition_from_privacy_preserving_transaction_deshielded() {
         let sender_keys = test_private_account_keys_1();
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
         let sender_nonce = Nonce(0xdead_beef);
 
         let sender_private_account = Account {
@@ -1448,7 +1462,7 @@ pub mod tests {
         );
 
         let expected_new_commitment = Commitment::new(
-            &sender_keys.npk(),
+            &sender_id,
             &Account {
                 program_owner: Program::authenticated_transfer_program().id(),
                 nonce: sender_nonce.private_account_nonce_increment(&sender_keys.nsk),
@@ -1457,7 +1471,7 @@ pub mod tests {
             },
         );
 
-        let sender_pre_commitment = Commitment::new(&sender_keys.npk(), &sender_private_account);
+        let sender_pre_commitment = Commitment::new(&sender_id, &sender_private_account);
         let expected_new_nullifier =
             Nullifier::for_account_update(&sender_pre_commitment, &sender_keys.nsk);
 
@@ -1500,6 +1514,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1526,6 +1541,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1552,6 +1568,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1578,6 +1595,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1612,6 +1630,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1638,6 +1657,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1673,6 +1693,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1699,6 +1720,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1734,6 +1756,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1771,6 +1794,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1781,7 +1805,11 @@ pub mod tests {
     fn circuit_fails_if_insufficient_nonces_are_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1789,10 +1817,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         let result = execute_and_prove(
             vec![private_account_1, private_account_2],
@@ -1809,6 +1837,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -1820,6 +1849,8 @@ pub mod tests {
     fn circuit_fails_if_insufficient_keys_are_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1827,7 +1858,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
             AccountWithMetadata::new(Account::default(), false, AccountId::new([1; 32]));
@@ -1843,6 +1874,7 @@ pub mod tests {
             vec![1, 2],
             private_account_keys.to_vec(),
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -1854,7 +1886,11 @@ pub mod tests {
     fn circuit_fails_if_insufficient_commitment_proofs_are_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1862,10 +1898,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         // Setting no second commitment proof.
         let private_account_membership_proofs = [Some((0, vec![]))];
@@ -1884,6 +1920,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             private_account_membership_proofs.to_vec(),
             &program.into(),
         );
@@ -1895,7 +1932,11 @@ pub mod tests {
     fn circuit_fails_if_insufficient_auth_keys_are_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1903,10 +1944,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         // Setting no auth key for an execution with one non default private accounts.
         let private_account_nsks = [];
@@ -1926,6 +1967,7 @@ pub mod tests {
             ],
             private_account_nsks.to_vec(),
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -1936,7 +1978,11 @@ pub mod tests {
     fn circuit_fails_if_invalid_auth_keys_are_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1944,10 +1990,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         let private_account_keys = [
             // First private account is the sender
@@ -1973,6 +2019,7 @@ pub mod tests {
             vec![1, 2],
             private_account_keys.to_vec(),
             private_account_nsks.to_vec(),
+            vec![],
             private_account_membership_proofs.to_vec(),
             &program.into(),
         );
@@ -1984,7 +2031,11 @@ pub mod tests {
     fn circuit_should_fail_if_new_private_account_with_non_default_balance_is_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -1992,7 +2043,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 = AccountWithMetadata::new(
             Account {
@@ -2001,7 +2052,7 @@ pub mod tests {
                 ..Account::default()
             },
             false,
-            &recipient_keys.npk(),
+            recipient_account_id,
         );
 
         let result = execute_and_prove(
@@ -2019,6 +2070,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2030,7 +2082,11 @@ pub mod tests {
     fn circuit_should_fail_if_new_private_account_with_non_default_program_owner_is_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2038,7 +2094,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 = AccountWithMetadata::new(
             Account {
@@ -2047,7 +2103,7 @@ pub mod tests {
                 ..Account::default()
             },
             false,
-            &recipient_keys.npk(),
+            recipient_account_id,
         );
 
         let result = execute_and_prove(
@@ -2065,6 +2121,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2076,7 +2133,11 @@ pub mod tests {
     fn circuit_should_fail_if_new_private_account_with_non_default_data_is_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2084,7 +2145,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 = AccountWithMetadata::new(
             Account {
@@ -2093,7 +2154,7 @@ pub mod tests {
                 ..Account::default()
             },
             false,
-            &recipient_keys.npk(),
+            recipient_account_id,
         );
 
         let result = execute_and_prove(
@@ -2111,6 +2172,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2122,7 +2184,11 @@ pub mod tests {
     fn circuit_should_fail_if_new_private_account_with_non_default_nonce_is_provided() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2130,7 +2196,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 = AccountWithMetadata::new(
             Account {
@@ -2139,7 +2205,7 @@ pub mod tests {
                 ..Account::default()
             },
             false,
-            &recipient_keys.npk(),
+            recipient_account_id,
         );
 
         let result = execute_and_prove(
@@ -2157,6 +2223,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2169,7 +2236,11 @@ pub mod tests {
      {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(1_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2177,13 +2248,13 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 = AccountWithMetadata::new(
             Account::default(),
             // This should be set to false in normal circumstances
             true,
-            &recipient_keys.npk(),
+            recipient_account_id,
         );
 
         let result = execute_and_prove(
@@ -2201,6 +2272,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![Identifier(0_u128), Identifier(1_u128)],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2231,6 +2303,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -2241,7 +2314,11 @@ pub mod tests {
     fn circuit_should_fail_with_too_many_nonces() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2249,10 +2326,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         let result = execute_and_prove(
             vec![private_account_1, private_account_2],
@@ -2269,6 +2346,7 @@ pub mod tests {
                 ),
             ],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2280,7 +2358,11 @@ pub mod tests {
     fn circuit_should_fail_with_too_many_private_account_keys() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2288,10 +2370,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         // Setting three private account keys for a circuit execution with only two private
         // accounts.
@@ -2315,6 +2397,7 @@ pub mod tests {
             vec![1, 2],
             private_account_keys.to_vec(),
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -2326,7 +2409,11 @@ pub mod tests {
     fn circuit_should_fail_with_too_many_private_account_auth_keys() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let recipient_keys = test_private_account_keys_2();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2334,10 +2421,10 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
         let private_account_2 =
-            AccountWithMetadata::new(Account::default(), false, &recipient_keys.npk());
+            AccountWithMetadata::new(Account::default(), false, recipient_account_id);
 
         // Setting two private account keys for a circuit execution with only one non default
         // private account (visibility mask equal to 1 means that auth keys are expected).
@@ -2359,6 +2446,7 @@ pub mod tests {
                 ),
             ],
             private_account_nsks.to_vec(),
+            vec![],
             private_account_membership_proofs.to_vec(),
             &program.into(),
         );
@@ -2397,7 +2485,7 @@ pub mod tests {
             .transition_from_privacy_preserving_transaction(&tx, 1, 0)
             .unwrap();
 
-        let sender_private_account = Account {
+        let _sender_private_account = Account {
             program_owner: Program::authenticated_transfer_program().id(),
             balance: 100,
             nonce: sender_nonce,
@@ -2426,6 +2514,8 @@ pub mod tests {
     fn circuit_should_fail_if_there_are_repeated_ids() {
         let program = Program::simple_balance_transfer();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
         let private_account_1 = AccountWithMetadata::new(
             Account {
                 program_owner: program.id(),
@@ -2433,7 +2523,7 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &sender_keys.npk(),
+            sender_account_id,
         );
 
         let visibility_mask = [1, 1];
@@ -2449,6 +2539,7 @@ pub mod tests {
                 (sender_keys.npk(), shared_secret),
             ],
             private_account_nsks.to_vec(),
+            vec![],
             private_account_membership_proofs.to_vec(),
             &program.into(),
         );
@@ -2460,13 +2551,13 @@ pub mod tests {
     fn claiming_mechanism() {
         let program = Program::authenticated_transfer_program();
         let from_key = PrivateKey::try_new([1; 32]).unwrap();
-        let from = AccountId::from(&PublicKey::new_from_private_key(&from_key));
+        let from = AccountId::public_account_id(&PublicKey::new_from_private_key(&from_key));
         let initial_balance = 100;
         let initial_data = [(from, initial_balance)];
         let mut state =
             V03State::new_with_genesis_accounts(&initial_data, &[], 0).with_test_programs();
         let to_key = PrivateKey::try_new([2; 32]).unwrap();
-        let to = AccountId::from(&PublicKey::new_from_private_key(&to_key));
+        let to = AccountId::public_account_id(&PublicKey::new_from_private_key(&to_key));
         let amount: u128 = 37;
 
         // Check the recipient is an uninitialized account
@@ -2501,7 +2592,8 @@ pub mod tests {
     fn unauthorized_public_account_claiming_fails() {
         let program = Program::authenticated_transfer_program();
         let account_key = PrivateKey::try_new([9; 32]).unwrap();
-        let account_id = AccountId::from(&PublicKey::new_from_private_key(&account_key));
+        let account_id =
+            AccountId::public_account_id(&PublicKey::new_from_private_key(&account_key));
         let mut state = V03State::new_with_genesis_accounts(&[], &[], 0);
 
         assert_eq!(state.get_account_by_id(account_id), Account::default());
@@ -2522,7 +2614,8 @@ pub mod tests {
     fn authorized_public_account_claiming_succeeds() {
         let program = Program::authenticated_transfer_program();
         let account_key = PrivateKey::try_new([10; 32]).unwrap();
-        let account_id = AccountId::from(&PublicKey::new_from_private_key(&account_key));
+        let account_id =
+            AccountId::public_account_id(&PublicKey::new_from_private_key(&account_key));
         let mut state = V03State::new_with_genesis_accounts(&[], &[], 0);
 
         assert_eq!(state.get_account_by_id(account_id), Account::default());
@@ -2553,7 +2646,7 @@ pub mod tests {
     fn public_chained_call() {
         let program = Program::chain_caller();
         let key = PrivateKey::try_new([1; 32]).unwrap();
-        let from = AccountId::from(&PublicKey::new_from_private_key(&key));
+        let from = AccountId::public_account_id(&PublicKey::new_from_private_key(&key));
         let to = AccountId::new([2; 32]);
         let initial_balance = 1000;
         let initial_data = [(from, initial_balance), (to, 0)];
@@ -2598,7 +2691,7 @@ pub mod tests {
     fn execution_fails_if_chained_calls_exceeds_depth() {
         let program = Program::chain_caller();
         let key = PrivateKey::try_new([1; 32]).unwrap();
-        let from = AccountId::from(&PublicKey::new_from_private_key(&key));
+        let from = AccountId::public_account_id(&PublicKey::new_from_private_key(&key));
         let to = AccountId::new([2; 32]);
         let initial_balance = 100;
         let initial_data = [(from, initial_balance), (to, 0)];
@@ -2683,13 +2776,13 @@ pub mod tests {
         let chain_caller = Program::chain_caller();
         let auth_transfer = Program::authenticated_transfer_program();
         let from_key = PrivateKey::try_new([1; 32]).unwrap();
-        let from = AccountId::from(&PublicKey::new_from_private_key(&from_key));
+        let from = AccountId::public_account_id(&PublicKey::new_from_private_key(&from_key));
         let initial_balance = 100;
         let initial_data = [(from, initial_balance)];
         let mut state =
             V03State::new_with_genesis_accounts(&initial_data, &[], 0).with_test_programs();
         let to_key = PrivateKey::try_new([2; 32]).unwrap();
-        let to = AccountId::from(&PublicKey::new_from_private_key(&to_key));
+        let to = AccountId::public_account_id(&PublicKey::new_from_private_key(&to_key));
         let amount: u128 = 37;
 
         // Check the recipient is an uninitialized account
@@ -2744,6 +2837,7 @@ pub mod tests {
             vec![],
             vec![],
             vec![],
+            vec![],
             &program.into(),
         );
 
@@ -2755,20 +2849,23 @@ pub mod tests {
         let program = Program::authenticated_transfer_program();
         let program_id = program.id();
         let sender_keys = test_private_account_keys_1();
+        let sender_account_id =
+            AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
         let sender_private_account = Account {
             program_owner: program_id,
             balance: 100,
             ..Account::default()
         };
-        let sender_commitment = Commitment::new(&sender_keys.npk(), &sender_private_account);
+        let sender_commitment = Commitment::new(&sender_account_id, &sender_private_account);
         let mut state =
             V03State::new_with_genesis_accounts(&[], std::slice::from_ref(&sender_commitment), 0);
-        let sender_pre = AccountWithMetadata::new(sender_private_account, true, &sender_keys.npk());
+        let sender_pre = AccountWithMetadata::new(sender_private_account, true, sender_account_id);
         let recipient_private_key = PrivateKey::try_new([2; 32]).unwrap();
         let recipient_account_id =
-            AccountId::from(&PublicKey::new_from_private_key(&recipient_private_key));
+            AccountId::public_account_id(&PublicKey::new_from_private_key(&recipient_private_key));
         let recipient_pre =
             AccountWithMetadata::new(Account::default(), true, recipient_account_id);
+
         let esk = [5; 32];
         let shared_secret = SharedSecretKey::new(&esk, &sender_keys.vpk());
         let epk = EphemeralPublicKey::from_scalar(esk);
@@ -2779,6 +2876,7 @@ pub mod tests {
             vec![1, 0],
             vec![(sender_keys.npk(), shared_secret)],
             vec![sender_keys.nsk],
+            vec![sender_keys.identifier],
             vec![state.get_proof_for_commitment(&sender_commitment)],
             &program.into(),
         )
@@ -2787,7 +2885,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![recipient_account_id],
             vec![Nonce(0)],
-            vec![(sender_keys.npk(), sender_keys.vpk(), epk)],
+            vec![(sender_account_id, sender_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -2822,6 +2920,7 @@ pub mod tests {
         let from_keys = test_private_account_keys_1();
         let to_keys = test_private_account_keys_2();
         let initial_balance = 100;
+        let from_account_id = AccountId::private_account_id(&from_keys.npk(), from_keys.identifier);
         let from_account = AccountWithMetadata::new(
             Account {
                 program_owner: auth_transfers.id(),
@@ -2829,19 +2928,20 @@ pub mod tests {
                 ..Account::default()
             },
             true,
-            &from_keys.npk(),
+            from_account_id,
         );
+        let to_account_id = AccountId::private_account_id(&to_keys.npk(), to_keys.identifier);
         let to_account = AccountWithMetadata::new(
             Account {
                 program_owner: auth_transfers.id(),
                 ..Account::default()
             },
             true,
-            &to_keys.npk(),
+            to_account_id,
         );
 
-        let from_commitment = Commitment::new(&from_keys.npk(), &from_account.account);
-        let to_commitment = Commitment::new(&to_keys.npk(), &to_account.account);
+        let from_commitment = Commitment::new(&from_account_id, &from_account.account);
+        let to_commitment = Commitment::new(&to_account_id, &to_account.account);
         let mut state = V03State::new_with_genesis_accounts(
             &[],
             &[from_commitment.clone(), to_commitment.clone()],
@@ -2877,14 +2977,14 @@ pub mod tests {
             nonce: from_new_nonce,
             ..from_account.account.clone()
         };
-        let from_expected_commitment = Commitment::new(&from_keys.npk(), &from_expected_post);
+        let from_expected_commitment = Commitment::new(&from_account_id, &from_expected_post);
 
         let to_expected_post = Account {
             balance: u128::from(number_of_calls) * amount,
             nonce: to_new_nonce,
             ..to_account.account.clone()
         };
-        let to_expected_commitment = Commitment::new(&to_keys.npk(), &to_expected_post);
+        let to_expected_commitment = Commitment::new(&to_account_id, &to_expected_post);
 
         // Act
         let (output, proof) = execute_and_prove(
@@ -2893,6 +2993,7 @@ pub mod tests {
             vec![1, 1],
             vec![(from_keys.npk(), to_ss), (to_keys.npk(), from_ss)],
             vec![from_keys.nsk, to_keys.nsk],
+            vec![from_keys.identifier, to_keys.identifier],
             vec![
                 state.get_proof_for_commitment(&from_commitment),
                 state.get_proof_for_commitment(&to_commitment),
@@ -2905,8 +3006,8 @@ pub mod tests {
             vec![],
             vec![],
             vec![
-                (to_keys.npk(), to_keys.vpk(), to_epk),
-                (from_keys.npk(), from_keys.vpk(), from_epk),
+                (to_account_id, to_keys.vpk(), to_epk),
+                (from_account_id, from_keys.vpk(), from_epk),
             ],
             output,
         )
@@ -3052,11 +3153,12 @@ pub mod tests {
     #[test]
     fn malicious_program_cannot_break_balance_validation() {
         let sender_key = PrivateKey::try_new([37; 32]).unwrap();
-        let sender_id = AccountId::from(&PublicKey::new_from_private_key(&sender_key));
+        let sender_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&sender_key));
         let sender_init_balance: u128 = 10;
 
         let recipient_key = PrivateKey::try_new([42; 32]).unwrap();
-        let recipient_id = AccountId::from(&PublicKey::new_from_private_key(&recipient_key));
+        let recipient_id =
+            AccountId::public_account_id(&PublicKey::new_from_private_key(&recipient_key));
         let recipient_init_balance: u128 = 10;
 
         let mut state = V03State::new_with_genesis_accounts(
@@ -3119,10 +3221,11 @@ pub mod tests {
 
         // Set up keys for the authorized private account
         let private_keys = test_private_account_keys_1();
+        let account_id =
+            AccountId::private_account_id(&private_keys.npk(), private_keys.identifier);
 
         // Create an authorized private account with default values (new account being initialized)
-        let authorized_account =
-            AccountWithMetadata::new(Account::default(), true, &private_keys.npk());
+        let authorized_account = AccountWithMetadata::new(Account::default(), true, account_id);
 
         let program = Program::authenticated_transfer_program();
 
@@ -3141,6 +3244,7 @@ pub mod tests {
             vec![1],
             vec![(private_keys.npk(), shared_secret)],
             vec![private_keys.nsk],
+            vec![private_keys.identifier],
             vec![None],
             &program.into(),
         )
@@ -3150,7 +3254,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![],
             vec![],
-            vec![(private_keys.npk(), private_keys.vpk(), epk)],
+            vec![(account_id, private_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -3161,7 +3265,7 @@ pub mod tests {
         let result = state.transition_from_privacy_preserving_transaction(&tx, 1, 0);
         assert!(result.is_ok());
 
-        let nullifier = Nullifier::for_account_initialization(&private_keys.npk());
+        let nullifier = Nullifier::for_account_initialization(&account_id);
         assert!(state.private_state.1.contains(&nullifier));
     }
 
@@ -3170,12 +3274,13 @@ pub mod tests {
         let mut state = V03State::new_with_genesis_accounts(&[], &[], 0).with_test_programs();
 
         let private_keys = test_private_account_keys_1();
+        let account_id =
+            AccountId::private_account_id(&private_keys.npk(), private_keys.identifier);
         // This is intentional: claim authorization was introduced to protect public accounts,
         // especially PDAs. Private PDAs are not useful in practice because there is no way to
         // operate them without the corresponding private keys, so unauthorized private claiming
         // remains allowed.
-        let unauthorized_account =
-            AccountWithMetadata::new(Account::default(), false, &private_keys.npk());
+        let unauthorized_account = AccountWithMetadata::new(Account::default(), false, account_id);
 
         let program = Program::claimer();
         let esk = [5; 32];
@@ -3188,6 +3293,7 @@ pub mod tests {
             vec![2],
             vec![(private_keys.npk(), shared_secret)],
             vec![],
+            vec![private_keys.identifier],
             vec![None],
             &program.into(),
         )
@@ -3196,7 +3302,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![],
             vec![],
-            vec![(private_keys.npk(), private_keys.vpk(), epk)],
+            vec![(account_id, private_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -3208,7 +3314,7 @@ pub mod tests {
             .transition_from_privacy_preserving_transaction(&tx, 1, 0)
             .unwrap();
 
-        let nullifier = Nullifier::for_account_initialization(&private_keys.npk());
+        let nullifier = Nullifier::for_account_initialization(&account_id);
         assert!(state.private_state.1.contains(&nullifier));
     }
 
@@ -3218,10 +3324,11 @@ pub mod tests {
 
         // Set up keys for the private account
         let private_keys = test_private_account_keys_1();
+        let account_id =
+            AccountId::private_account_id(&private_keys.npk(), private_keys.identifier);
 
         // Step 1: Create a new private account with authorization
-        let authorized_account =
-            AccountWithMetadata::new(Account::default(), true, &private_keys.npk());
+        let authorized_account = AccountWithMetadata::new(Account::default(), true, account_id);
 
         let claimer_program = Program::claimer();
 
@@ -3239,6 +3346,7 @@ pub mod tests {
             vec![1],
             vec![(private_keys.npk(), shared_secret)],
             vec![private_keys.nsk],
+            vec![private_keys.identifier],
             vec![None],
             &claimer_program.into(),
         )
@@ -3247,7 +3355,7 @@ pub mod tests {
         let message = Message::try_from_circuit_output(
             vec![],
             vec![],
-            vec![(private_keys.npk(), private_keys.vpk(), epk)],
+            vec![(account_id, private_keys.vpk(), epk)],
             output,
         )
         .unwrap();
@@ -3263,7 +3371,7 @@ pub mod tests {
         );
 
         // Verify the account is now initialized (nullifier exists)
-        let nullifier = Nullifier::for_account_initialization(&private_keys.npk());
+        let nullifier = Nullifier::for_account_initialization(&account_id);
         assert!(state.private_state.1.contains(&nullifier));
 
         // Prepare new state of account
@@ -3284,6 +3392,7 @@ pub mod tests {
             vec![1],
             vec![(private_keys.npk(), shared_secret2)],
             vec![private_keys.nsk],
+            vec![],
             vec![None],
             &noop_program.into(),
         );
@@ -3342,8 +3451,8 @@ pub mod tests {
     fn private_changer_claimer_no_data_change_no_claim_succeeds() {
         let program = Program::changer_claimer();
         let sender_keys = test_private_account_keys_1();
-        let private_account =
-            AccountWithMetadata::new(Account::default(), true, &sender_keys.npk());
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), sender_keys.identifier);
+        let private_account = AccountWithMetadata::new(Account::default(), true, sender_id);
         // Don't change data (None) and don't claim (false)
         let instruction: (Option<Vec<u8>>, bool) = (None, false);
 
@@ -3356,6 +3465,7 @@ pub mod tests {
                 SharedSecretKey::new(&[3; 32], &sender_keys.vpk()),
             )],
             vec![sender_keys.nsk],
+            vec![sender_keys.identifier],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -3368,8 +3478,8 @@ pub mod tests {
     fn private_changer_claimer_data_change_no_claim_fails() {
         let program = Program::changer_claimer();
         let sender_keys = test_private_account_keys_1();
-        let private_account =
-            AccountWithMetadata::new(Account::default(), true, &sender_keys.npk());
+        let sender_id = AccountId::private_account_id(&sender_keys.npk(), Identifier(0_u128));
+        let private_account = AccountWithMetadata::new(Account::default(), true, sender_id);
         // Change data but don't claim (false) - should fail
         let new_data = vec![1, 2, 3, 4, 5];
         let instruction: (Option<Vec<u8>>, bool) = (Some(new_data), false);
@@ -3383,6 +3493,7 @@ pub mod tests {
                 SharedSecretKey::new(&[3; 32], &sender_keys.vpk()),
             )],
             vec![sender_keys.nsk],
+            vec![],
             vec![Some((0, vec![]))],
             &program.into(),
         );
@@ -3398,6 +3509,8 @@ pub mod tests {
         let auth_transfers = Program::authenticated_transfer_program();
         let sender_keys = test_public_account_keys_1();
         let recipient_keys = test_private_account_keys_1();
+        let recipient_account_id =
+            AccountId::private_account_id(&recipient_keys.npk(), Identifier(0_u128));
 
         let sender_account = AccountWithMetadata::new(
             Account {
@@ -3409,10 +3522,9 @@ pub mod tests {
             sender_keys.account_id(),
         );
         let recipient_account =
-            AccountWithMetadata::new(Account::default(), true, &recipient_keys.npk());
-
+            AccountWithMetadata::new(Account::default(), true, recipient_account_id);
         let recipient_commitment =
-            Commitment::new(&recipient_keys.npk(), &recipient_account.account);
+            Commitment::new(&recipient_account_id, &recipient_account.account);
         let state = V03State::new_with_genesis_accounts(
             &[(sender_account.account_id, sender_account.account.balance)],
             std::slice::from_ref(&recipient_commitment),
@@ -3437,6 +3549,7 @@ pub mod tests {
             vec![0, 1],
             vec![(recipient_keys.npk(), recipient)],
             vec![recipient_keys.nsk],
+            vec![],
             vec![state.get_proof_for_commitment(&recipient_commitment)],
             &program_with_deps,
         );
@@ -3570,7 +3683,9 @@ pub mod tests {
         let block_validity_window: BlockValidityWindow = validity_window.try_into().unwrap();
         let validity_window_program = Program::validity_window();
         let account_keys = test_private_account_keys_1();
-        let pre = AccountWithMetadata::new(Account::default(), false, &account_keys.npk());
+        let account_id =
+            AccountId::private_account_id(&account_keys.npk(), account_keys.identifier);
+        let pre = AccountWithMetadata::new(Account::default(), false, account_id);
         let mut state = V03State::new_with_genesis_accounts(&[], &[], 0).with_test_programs();
         let tx = {
             let esk = [3; 32];
@@ -3587,6 +3702,7 @@ pub mod tests {
                 vec![2],
                 vec![(account_keys.npk(), shared_secret)],
                 vec![],
+                vec![account_keys.identifier],
                 vec![None],
                 &validity_window_program.into(),
             )
@@ -3595,11 +3711,11 @@ pub mod tests {
             let message = Message::try_from_circuit_output(
                 vec![],
                 vec![],
-                vec![(account_keys.npk(), account_keys.vpk(), epk)],
+                vec![(account_id, account_keys.vpk(), epk)],
                 output,
             )
             .unwrap();
-
+            //
             let witness_set = WitnessSet::for_message(&message, proof, &[]);
             PrivacyPreservingTransaction::new(message, witness_set)
         };
@@ -3639,7 +3755,9 @@ pub mod tests {
             validity_window.try_into().unwrap();
         let validity_window_program = Program::validity_window();
         let account_keys = test_private_account_keys_1();
-        let pre = AccountWithMetadata::new(Account::default(), false, &account_keys.npk());
+        let account_id =
+            AccountId::private_account_id(&account_keys.npk(), account_keys.identifier);
+        let pre = AccountWithMetadata::new(Account::default(), false, account_id);
         let mut state = V03State::new_with_genesis_accounts(&[], &[], 0).with_test_programs();
         let tx = {
             let esk = [3; 32];
@@ -3656,6 +3774,7 @@ pub mod tests {
                 vec![2],
                 vec![(account_keys.npk(), shared_secret)],
                 vec![],
+                vec![account_keys.identifier],
                 vec![None],
                 &validity_window_program.into(),
             )
@@ -3664,7 +3783,7 @@ pub mod tests {
             let message = Message::try_from_circuit_output(
                 vec![],
                 vec![],
-                vec![(account_keys.npk(), account_keys.vpk(), epk)],
+                vec![(account_id, account_keys.vpk(), epk)],
                 output,
             )
             .unwrap();
@@ -3718,7 +3837,7 @@ pub mod tests {
             V03State::new_with_genesis_accounts(&[(recipient_id, 0)], &[], genesis_timestamp)
                 .with_test_programs();
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
-        let sender_id = AccountId::from(&PublicKey::new_from_private_key(&key1));
+        let sender_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
         state.force_insert_account(
             sender_id,
             Account {
@@ -3761,7 +3880,7 @@ pub mod tests {
             V03State::new_with_genesis_accounts(&[(recipient_id, 0)], &[], genesis_timestamp)
                 .with_test_programs();
         let key1 = PrivateKey::try_new([1; 32]).unwrap();
-        let sender_id = AccountId::from(&PublicKey::new_from_private_key(&key1));
+        let sender_id = AccountId::public_account_id(&PublicKey::new_from_private_key(&key1));
         state.force_insert_account(
             sender_id,
             Account {
diff --git a/program_methods/guest/src/bin/privacy_preserving_circuit.rs b/program_methods/guest/src/bin/privacy_preserving_circuit.rs
index 1d091e1c..3fc511e7 100644
--- a/program_methods/guest/src/bin/privacy_preserving_circuit.rs
+++ b/program_methods/guest/src/bin/privacy_preserving_circuit.rs
@@ -7,7 +7,7 @@ use nssa_core::{
     Commitment, CommitmentSetDigest, DUMMY_COMMITMENT_HASH, EncryptionScheme, MembershipProof,
     Nullifier, NullifierPublicKey, NullifierSecretKey, PrivacyPreservingCircuitInput,
     PrivacyPreservingCircuitOutput, SharedSecretKey,
-    account::{Account, AccountId, AccountWithMetadata, Nonce},
+    account::{Account, AccountId, AccountWithMetadata, Identifier, Nonce},
     compute_digest_for_path,
     program::{
         AccountPostState, BlockValidityWindow, ChainedCall, Claim, DEFAULT_PROGRAM_ID,
@@ -304,6 +304,7 @@ fn compute_circuit_output(
     visibility_mask: &[u8],
     private_account_keys: &[(NullifierPublicKey, SharedSecretKey)],
     private_account_nsks: &[NullifierSecretKey],
+    private_account_identifiers: &[Identifier],
     private_account_membership_proofs: &[Option<MembershipProof>],
 ) -> PrivacyPreservingCircuitOutput {
     let mut output = PrivacyPreservingCircuitOutput {
@@ -326,6 +327,7 @@ fn compute_circuit_output(
     let mut private_keys_iter = private_account_keys.iter();
     let mut private_nsks_iter = private_account_nsks.iter();
     let mut private_membership_proofs_iter = private_account_membership_proofs.iter();
+    let mut private_identifiers_iter = private_account_identifiers.iter();
 
     let mut output_index = 0;
     for (account_visibility_mask, (pre_state, post_state)) in
@@ -342,8 +344,12 @@ fn compute_circuit_output(
                     panic!("Missing private account key");
                 };
 
+                let Some(identifier) = private_identifiers_iter.next() else {
+                    panic!("Missing private account identifier");
+                };
+
                 assert_eq!(
-                    AccountId::from(npk),
+                    AccountId::private_account_id(npk, *identifier),
                     pre_state.account_id,
                     "AccountId mismatch"
                 );
@@ -371,11 +377,11 @@ fn compute_circuit_output(
                     let Some(membership_proof_opt) = private_membership_proofs_iter.next() else {
                         panic!("Missing membership proof");
                     };
-
+                    // TODO: here is the issue
                     let new_nullifier = compute_nullifier_and_set_digest(
                         membership_proof_opt.as_ref(),
                         &pre_state.account,
-                        npk,
+                        &pre_state.account_id,
                         nsk,
                     );
 
@@ -405,7 +411,8 @@ fn compute_circuit_output(
                         "Membership proof must be None for unauthorized accounts"
                     );
 
-                    let nullifier = Nullifier::for_account_initialization(npk);
+                    let account_id = AccountId::private_account_id(npk, *identifier);
+                    let nullifier = Nullifier::for_account_initialization(&account_id);
 
                     let new_nonce = Nonce::private_account_nonce_init(npk);
 
@@ -418,7 +425,8 @@ fn compute_circuit_output(
                 post_with_updated_nonce.nonce = new_nonce;
 
                 // Compute commitment
-                let commitment_post = Commitment::new(npk, &post_with_updated_nonce);
+                let commitment_post =
+                    Commitment::new(&pre_state.account_id, &post_with_updated_nonce);
 
                 // Encrypt and push post state
                 let encrypted_account = EncryptionScheme::encrypt(
@@ -456,10 +464,11 @@ fn compute_circuit_output(
     output
 }
 
+// Marvin: todo
 fn compute_nullifier_and_set_digest(
     membership_proof_opt: Option<&MembershipProof>,
     pre_account: &Account,
-    npk: &NullifierPublicKey,
+    account_id: &AccountId,
     nsk: &NullifierSecretKey,
 ) -> (Nullifier, CommitmentSetDigest) {
     membership_proof_opt.as_ref().map_or_else(
@@ -467,16 +476,16 @@ fn compute_nullifier_and_set_digest(
             assert_eq!(
                 *pre_account,
                 Account::default(),
-                "Found new private account with non default values"
+                "Found new private account with non default values$Marvin$"
             );
 
             // Compute initialization nullifier
-            let nullifier = Nullifier::for_account_initialization(npk);
+            let nullifier = Nullifier::for_account_initialization(account_id);
             (nullifier, DUMMY_COMMITMENT_HASH)
         },
         |membership_proof| {
             // Compute commitment set digest associated with provided auth path
-            let commitment_pre = Commitment::new(npk, pre_account);
+            let commitment_pre = Commitment::new(account_id, pre_account);
             let set_digest = compute_digest_for_path(&commitment_pre, membership_proof);
 
             // Compute update nullifier
@@ -492,6 +501,7 @@ fn main() {
         visibility_mask,
         private_account_keys,
         private_account_nsks,
+        private_account_identifiers,
         private_account_membership_proofs,
         program_id,
     } = env::read();
@@ -504,6 +514,7 @@ fn main() {
         &visibility_mask,
         &private_account_keys,
         &private_account_nsks,
+        &private_account_identifiers,
         &private_account_membership_proofs,
     );
 
diff --git a/programs/amm/src/tests.rs b/programs/amm/src/tests.rs
index 43e20168..c29b818a 100644
--- a/programs/amm/src/tests.rs
+++ b/programs/amm/src/tests.rs
@@ -4,10 +4,9 @@ use amm_core::{
     PoolDefinition, compute_liquidity_token_pda, compute_liquidity_token_pda_seed,
     compute_pool_pda, compute_vault_pda, compute_vault_pda_seed,
 };
-use nssa::{
-    PrivateKey, PublicKey, PublicTransaction, V03State, program::Program, public_transaction,
-};
+use nssa::{PublicTransaction, V03State, program::Program, public_transaction};
 use nssa_core::{
+    PrivateKey, PublicKey,
     account::{Account, AccountId, AccountWithMetadata, Data},
     program::{ChainedCall, ProgramId},
 };
@@ -1314,19 +1313,19 @@ impl IdForExeTests {
     }
 
     fn user_token_a_id() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(
+        AccountId::public_account_id(&PublicKey::new_from_private_key(
             &PrivateKeysForTests::user_token_a_key(),
         ))
     }
 
     fn user_token_b_id() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(
+        AccountId::public_account_id(&PublicKey::new_from_private_key(
             &PrivateKeysForTests::user_token_b_key(),
         ))
     }
 
     fn user_token_lp_id() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(
+        AccountId::public_account_id(&PublicKey::new_from_private_key(
             &PrivateKeysForTests::user_token_lp_key(),
         ))
     }
diff --git a/sequencer/core/src/block_store.rs b/sequencer/core/src/block_store.rs
index 46f71797..2185b01a 100644
--- a/sequencer/core/src/block_store.rs
+++ b/sequencer/core/src/block_store.rs
@@ -14,7 +14,7 @@ pub struct SequencerStore {
     // TODO: Consider adding the hashmap to the database for faster recovery.
     tx_hash_to_block_map: HashMap<HashType, u64>,
     genesis_id: u64,
-    signing_key: nssa::PrivateKey,
+    signing_key: nssa_core::PrivateKey,
 }
 
 impl SequencerStore {
@@ -26,7 +26,7 @@ impl SequencerStore {
         location: &Path,
         genesis_block: &Block,
         genesis_msg_id: MantleMsgId,
-        signing_key: nssa::PrivateKey,
+        signing_key: nssa_core::PrivateKey,
     ) -> Result<Self> {
         let tx_hash_to_block_map = block_to_transactions_map(genesis_block);
 
@@ -80,7 +80,7 @@ impl SequencerStore {
         self.genesis_id
     }
 
-    pub const fn signing_key(&self) -> &nssa::PrivateKey {
+    pub const fn signing_key(&self) -> &nssa_core::PrivateKey {
         &self.signing_key
     }
 
diff --git a/sequencer/core/src/lib.rs b/sequencer/core/src/lib.rs
index 642d663a..28ef5875 100644
--- a/sequencer/core/src/lib.rs
+++ b/sequencer/core/src/lib.rs
@@ -15,7 +15,8 @@ use logos_blockchain_key_management_system_service::keys::{ED25519_SECRET_KEY_SI
 use mempool::{MemPool, MemPoolHandle};
 #[cfg(feature = "mock")]
 pub use mock::SequencerCoreWithMockClients;
-use nssa::V03State;
+use nssa::{AccountId, V03State};
+use nssa_core::account::Identifier;
 pub use storage::error::DbError;
 use testnet_initial_state::initial_state;
 
@@ -62,7 +63,7 @@ impl<BC: BlockSettlementClientTrait, IC: IndexerClientTrait> SequencerCore<BC, I
             timestamp: 0,
         };
 
-        let signing_key = nssa::PrivateKey::try_new(config.signing_key).unwrap();
+        let signing_key = nssa_core::PrivateKey::try_new(config.signing_key).unwrap();
         let genesis_parent_msg_id = [0; 32];
         let genesis_block = hashable_data.into_pending_block(&signing_key, genesis_parent_msg_id);
 
@@ -113,11 +114,11 @@ impl<BC: BlockSettlementClientTrait, IC: IndexerClientTrait> SequencerCore<BC, I
                             let npk = &init_comm_data.npk;
 
                             let mut acc = init_comm_data.account.clone();
-
+                            let acc_id = &AccountId::private_account_id(npk, Identifier(0_u128)); //TODO marvin
                             acc.program_owner =
                                 nssa::program::Program::authenticated_transfer_program().id();
 
-                            nssa_core::Commitment::new(npk, &acc)
+                            nssa_core::Commitment::new(acc_id, &acc)
                         })
                         .collect()
                 });
@@ -432,11 +433,11 @@ mod tests {
         }
     }
 
-    fn create_signing_key_for_account1() -> nssa::PrivateKey {
+    fn create_signing_key_for_account1() -> nssa_core::PrivateKey {
         initial_pub_accounts_private_keys()[0].pub_sign_key.clone()
     }
 
-    fn create_signing_key_for_account2() -> nssa::PrivateKey {
+    fn create_signing_key_for_account2() -> nssa_core::PrivateKey {
         initial_pub_accounts_private_keys()[1].pub_sign_key.clone()
     }
 
diff --git a/storage/Cargo.toml b/storage/Cargo.toml
index f18625cb..4733c3d5 100644
--- a/storage/Cargo.toml
+++ b/storage/Cargo.toml
@@ -10,6 +10,7 @@ workspace = true
 [dependencies]
 common.workspace = true
 nssa.workspace = true
+nssa_core.workspace = true
 
 thiserror.workspace = true
 borsh.workspace = true
diff --git a/storage/src/indexer/mod.rs b/storage/src/indexer/mod.rs
index 7ca89a56..b773fb2e 100644
--- a/storage/src/indexer/mod.rs
+++ b/storage/src/indexer/mod.rs
@@ -213,7 +213,8 @@ fn closest_breakpoint_id(block_id: u64) -> u64 {
 #[expect(clippy::shadow_unrelated, reason = "Fine for tests")]
 #[cfg(test)]
 mod tests {
-    use nssa::{AccountId, PublicKey};
+    use nssa::AccountId;
+    use nssa_core::PublicKey;
     use tempfile::tempdir;
 
     use super::*;
@@ -222,20 +223,20 @@ mod tests {
         common::test_utils::produce_dummy_block(1, None, vec![])
     }
 
-    fn acc1_sign_key() -> nssa::PrivateKey {
-        nssa::PrivateKey::try_new([1; 32]).unwrap()
+    fn acc1_sign_key() -> nssa_core::PrivateKey {
+        nssa_core::PrivateKey::try_new([1; 32]).unwrap()
     }
 
-    fn acc2_sign_key() -> nssa::PrivateKey {
-        nssa::PrivateKey::try_new([2; 32]).unwrap()
+    fn acc2_sign_key() -> nssa_core::PrivateKey {
+        nssa_core::PrivateKey::try_new([2; 32]).unwrap()
     }
 
     fn acc1() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(&acc1_sign_key()))
+        AccountId::public_account_id(&PublicKey::new_from_private_key(&acc1_sign_key()))
     }
 
     fn acc2() -> AccountId {
-        AccountId::from(&PublicKey::new_from_private_key(&acc2_sign_key()))
+        AccountId::public_account_id(&PublicKey::new_from_private_key(&acc2_sign_key()))
     }
 
     #[test]
diff --git a/testnet_initial_state/src/lib.rs b/testnet_initial_state/src/lib.rs
index 1d75d6a1..ef5c1036 100644
--- a/testnet_initial_state/src/lib.rs
+++ b/testnet_initial_state/src/lib.rs
@@ -3,8 +3,11 @@ use key_protocol::key_management::{
     KeyChain,
     secret_holders::{PrivateKeyHolder, SecretSpendingKey},
 };
-use nssa::{Account, AccountId, Data, PrivateKey, PublicKey, V03State};
-use nssa_core::{NullifierPublicKey, encryption::shared_key_derivation::Secp256k1Point};
+use nssa::{Account, AccountId, Data, V03State};
+use nssa_core::{
+    NullifierPublicKey, PrivateKey, PublicKey, account::Identifier,
+    encryption::shared_key_derivation::Secp256k1Point,
+};
 use serde::{Deserialize, Serialize};
 
 const PRIVATE_KEY_PUB_ACC_A: [u8; 32] = [
@@ -75,6 +78,9 @@ const PUB_ACC_B_INITIAL_BALANCE: u128 = 20000;
 const PRIV_ACC_A_INITIAL_BALANCE: u128 = 10000;
 const PRIV_ACC_B_INITIAL_BALANCE: u128 = 20000;
 
+const PRIV_ACC_A_IDENTIFIER: u128 = 13;
+const PRIV_ACC_B_IDENTIFIER: u128 = 42;
+
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct PublicAccountPublicInitialData {
     pub account_id: AccountId,
@@ -84,19 +90,21 @@ pub struct PublicAccountPublicInitialData {
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct PrivateAccountPublicInitialData {
     pub npk: nssa_core::NullifierPublicKey,
+    pub identifier: Identifier,
     pub account: nssa_core::account::Account,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 pub struct PublicAccountPrivateInitialData {
     pub account_id: nssa::AccountId,
-    pub pub_sign_key: nssa::PrivateKey,
+    pub pub_sign_key: nssa_core::PrivateKey,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct PrivateAccountPrivateInitialData {
     pub account_id: nssa::AccountId,
     pub account: nssa_core::account::Account,
+    pub identifier: Identifier,
     pub key_chain: KeyChain,
 }
 
@@ -108,11 +116,15 @@ pub fn initial_pub_accounts_private_keys() -> Vec<PublicAccountPrivateInitialDat
 
     vec![
         PublicAccountPrivateInitialData {
-            account_id: AccountId::from(&PublicKey::new_from_private_key(&acc1_pub_sign_key)),
+            account_id: AccountId::public_account_id(&PublicKey::new_from_private_key(
+                &acc1_pub_sign_key,
+            )),
             pub_sign_key: acc1_pub_sign_key,
         },
         PublicAccountPrivateInitialData {
-            account_id: AccountId::from(&PublicKey::new_from_private_key(&acc2_pub_sign_key)),
+            account_id: AccountId::public_account_id(&PublicKey::new_from_private_key(
+                &acc2_pub_sign_key,
+            )),
             pub_sign_key: acc2_pub_sign_key,
         },
     ]
@@ -140,25 +152,36 @@ pub fn initial_priv_accounts_private_keys() -> Vec<PrivateAccountPrivateInitialD
         viewing_public_key: Secp256k1Point(VPK_PRIV_ACC_B.to_vec()),
     };
 
+    let identifier_1 = Identifier(PRIV_ACC_A_IDENTIFIER);
+    let identifier_2 = Identifier(PRIV_ACC_B_IDENTIFIER);
+
     vec![
         PrivateAccountPrivateInitialData {
-            account_id: AccountId::from(&key_chain_1.nullifier_public_key),
+            account_id: AccountId::private_account_id(
+                &key_chain_1.nullifier_public_key,
+                Identifier(13_u128),
+            ),
             account: Account {
                 program_owner: DEFAULT_PROGRAM_OWNER,
                 balance: PRIV_ACC_A_INITIAL_BALANCE,
                 data: Data::default(),
                 nonce: 0.into(),
             },
+            identifier: identifier_1,
             key_chain: key_chain_1,
         },
         PrivateAccountPrivateInitialData {
-            account_id: AccountId::from(&key_chain_2.nullifier_public_key),
+            account_id: AccountId::private_account_id(
+                &key_chain_2.nullifier_public_key,
+                Identifier(42_u128),
+            ),
             account: Account {
                 program_owner: DEFAULT_PROGRAM_OWNER,
                 balance: PRIV_ACC_B_INITIAL_BALANCE,
                 data: Data::default(),
                 nonce: 0.into(),
             },
+            identifier: identifier_2,
             key_chain: key_chain_2,
         },
     ]
@@ -170,6 +193,7 @@ pub fn initial_commitments() -> Vec<PrivateAccountPublicInitialData> {
         .into_iter()
         .map(|data| PrivateAccountPublicInitialData {
             npk: data.key_chain.nullifier_public_key.clone(),
+            identifier: data.identifier,
             account: data.account,
         })
         .collect()
@@ -199,13 +223,14 @@ pub fn initial_state() -> V03State {
     let initial_commitments: Vec<nssa_core::Commitment> = initial_commitments()
         .iter()
         .map(|init_comm_data| {
-            let npk = &init_comm_data.npk;
+            let acc_id =
+                &AccountId::private_account_id(&init_comm_data.npk, init_comm_data.identifier);
 
             let mut acc = init_comm_data.account.clone();
 
             acc.program_owner = nssa::program::Program::authenticated_transfer_program().id();
 
-            nssa_core::Commitment::new(npk, &acc)
+            nssa_core::Commitment::new(acc_id, &acc)
         })
         .collect();
 
@@ -371,6 +396,7 @@ mod tests {
             init_comms[0],
             PrivateAccountPublicInitialData {
                 npk: NullifierPublicKey(NPK_PRIV_ACC_A),
+                identifier: Identifier(PRIV_ACC_A_IDENTIFIER),
                 account: Account {
                     program_owner: DEFAULT_PROGRAM_OWNER,
                     balance: PRIV_ACC_A_INITIAL_BALANCE,
@@ -384,6 +410,7 @@ mod tests {
             init_comms[1],
             PrivateAccountPublicInitialData {
                 npk: NullifierPublicKey(NPK_PRIV_ACC_B),
+                identifier: Identifier(PRIV_ACC_B_IDENTIFIER),
                 account: Account {
                     program_owner: DEFAULT_PROGRAM_OWNER,
                     balance: PRIV_ACC_B_INITIAL_BALANCE,
diff --git a/wallet-ffi/src/keys.rs b/wallet-ffi/src/keys.rs
index b8c95c55..227e3471 100644
--- a/wallet-ffi/src/keys.rs
+++ b/wallet-ffi/src/keys.rs
@@ -2,7 +2,8 @@
 
 use std::ptr;
 
-use nssa::{AccountId, PublicKey};
+use nssa::AccountId;
+use nssa_core::PublicKey;
 
 use crate::{
     error::{print_error, WalletFfiError},
diff --git a/wallet-ffi/src/types.rs b/wallet-ffi/src/types.rs
index 87c30315..caf987e1 100644
--- a/wallet-ffi/src/types.rs
+++ b/wallet-ffi/src/types.rs
@@ -249,15 +249,15 @@ impl TryFrom<&FfiAccount> for nssa::Account {
     }
 }
 
-impl From<nssa::PublicKey> for FfiPublicAccountKey {
-    fn from(value: nssa::PublicKey) -> Self {
+impl From<nssa_core::PublicKey> for FfiPublicAccountKey {
+    fn from(value: nssa_core::PublicKey) -> Self {
         Self {
             public_key: FfiBytes32::from_bytes(*value.value()),
         }
     }
 }
 
-impl TryFrom<&FfiPublicAccountKey> for nssa::PublicKey {
+impl TryFrom<&FfiPublicAccountKey> for nssa_core::PublicKey {
     type Error = WalletFfiError;
 
     fn try_from(value: &FfiPublicAccountKey) -> Result<Self, Self::Error> {
diff --git a/wallet/src/chain_storage.rs b/wallet/src/chain_storage.rs
index c9d07d08..e17998fe 100644
--- a/wallet/src/chain_storage.rs
+++ b/wallet/src/chain_storage.rs
@@ -86,6 +86,7 @@ impl WalletChainStore {
                             data.account_id,
                             PrivateBundle {
                                 key_chain: data.key_chain,
+                                identifier: data.identifier,
                                 account: data.account,
                             },
                         );
@@ -136,6 +137,7 @@ impl WalletChainStore {
                         data.account_id,
                         PrivateBundle {
                             key_chain: data.key_chain,
+                            identifier: data.identifier,
                             account,
                         },
                     );
@@ -211,7 +213,7 @@ impl WalletChainStore {
                         .private_key_tree
                         .key_map
                         .entry(chain_index.clone())
-                        .and_modify(|data| data.value.1 = account)
+                        .and_modify(|data| data.value.account = account)
                 });
         }
     }
diff --git a/wallet/src/cli/account.rs b/wallet/src/cli/account.rs
index 4283561e..87e0da3f 100644
--- a/wallet/src/cli/account.rs
+++ b/wallet/src/cli/account.rs
@@ -2,7 +2,8 @@ use anyhow::{Context as _, Result};
 use clap::Subcommand;
 use itertools::Itertools as _;
 use key_protocol::key_management::key_tree::chain_index::ChainIndex;
-use nssa::{Account, PublicKey, program::Program};
+use nssa::{Account, program::Program};
+use nssa_core::PublicKey;
 use sequencer_service_rpc::RpcClient as _;
 use token_core::{TokenDefinition, TokenHolding};
 
diff --git a/wallet/src/helperfunctions.rs b/wallet/src/helperfunctions.rs
index 6cfe00c8..3a548984 100644
--- a/wallet/src/helperfunctions.rs
+++ b/wallet/src/helperfunctions.rs
@@ -193,6 +193,7 @@ pub fn produce_data_for_storage(
             InitialAccountData::Private(Box::new(PrivateAccountPrivateInitialData {
                 account_id: *account_id,
                 account: bundle.account.clone(),
+                identifier: bundle.identifier,
                 key_chain: bundle.key_chain.clone(),
             }))
             .into(),
diff --git a/wallet/src/lib.rs b/wallet/src/lib.rs
index f4fdf2da..5ec695b3 100644
--- a/wallet/src/lib.rs
+++ b/wallet/src/lib.rs
@@ -287,7 +287,7 @@ impl WalletCore {
     pub fn get_account_public_signing_key(
         &self,
         account_id: AccountId,
-    ) -> Option<&nssa::PrivateKey> {
+    ) -> Option<&nssa_core::PrivateKey> {
         self.storage
             .user_data
             .get_pub_account_signing_key(account_id)
@@ -305,7 +305,10 @@ impl WalletCore {
     pub fn get_private_account_commitment(&self, account_id: AccountId) -> Option<Commitment> {
         let bundle = self.storage.user_data.get_private_account(account_id)?;
         Some(Commitment::new(
-            &bundle.key_chain.nullifier_public_key,
+            &AccountId::private_account_id(
+                &bundle.key_chain.nullifier_public_key,
+                bundle.identifier,
+            ),
             &bundle.account,
         ))
     }
@@ -393,6 +396,12 @@ impl WalletCore {
         )?;
 
         let private_account_keys = acc_manager.private_account_keys();
+        let private_account_identifiers =
+            acc_manager.private_account_identifiers(&private_account_keys);
+        // TODO: here. This is the function I want to use
+        // Okay. Now I have the "corrected" identifiers but NOT correct account_ids! (Marvin)
+        // -> So, we need to update AccountIds with these identifiers
+
         let (output, proof) = nssa::privacy_preserving_transaction::circuit::execute_and_prove(
             pre_states,
             instruction_data,
@@ -402,6 +411,7 @@ impl WalletCore {
                 .map(|keys| (keys.npk.clone(), keys.ssk))
                 .collect::<Vec<_>>(),
             acc_manager.private_account_auth(),
+            private_account_identifiers.clone(), // TODO: when was this done? Marvin
             acc_manager.private_account_membership_proofs(),
             &program.to_owned(),
         )
@@ -413,7 +423,14 @@ impl WalletCore {
                 Vec::from_iter(acc_manager.public_account_nonces()),
                 private_account_keys
                     .iter()
-                    .map(|keys| (keys.npk.clone(), keys.vpk.clone(), keys.epk.clone()))
+                    .zip(private_account_identifiers)
+                    .map(|(keys, identifier)| {
+                        (
+                            AccountId::private_account_id(&keys.npk.clone(), identifier),
+                            keys.vpk.clone(),
+                            keys.epk.clone(),
+                        )
+                    })
                     .collect(),
                 output,
             )
@@ -495,6 +512,7 @@ impl WalletCore {
                     acc_account_id,
                     PrivateBundle {
                         key_chain,
+                        identifier: _,
                         account: _,
                     },
                 )| (*acc_account_id, key_chain, None),
@@ -503,7 +521,7 @@ impl WalletCore {
                 |(chain_index, keys_node)| {
                     (
                         keys_node.account_id(),
-                        &keys_node.value.0,
+                        &keys_node.value.key_chain,
                         chain_index.index(),
                     )
                 },
@@ -511,8 +529,9 @@ impl WalletCore {
 
         let affected_accounts = private_account_key_chains
             .flat_map(|(acc_account_id, key_chain, index)| {
+                // Why index? Marvin
                 let view_tag = EncryptedAccountData::compute_view_tag(
-                    &key_chain.nullifier_public_key,
+                    &acc_account_id,
                     &key_chain.viewing_public_key,
                 );
 
diff --git a/wallet/src/privacy_preserving_tx.rs b/wallet/src/privacy_preserving_tx.rs
index e70c928e..e24f5206 100644
--- a/wallet/src/privacy_preserving_tx.rs
+++ b/wallet/src/privacy_preserving_tx.rs
@@ -1,9 +1,9 @@
 use anyhow::Result;
 use key_protocol::key_management::ephemeral_key_holder::EphemeralKeyHolder;
-use nssa::{AccountId, PrivateKey};
+use nssa::AccountId;
 use nssa_core::{
-    MembershipProof, NullifierPublicKey, NullifierSecretKey, SharedSecretKey,
-    account::{AccountWithMetadata, Nonce},
+    MembershipProof, NullifierPublicKey, NullifierSecretKey, PrivateKey, SharedSecretKey,
+    account::{AccountWithMetadata, Identifier, Nonce},
     encryption::{EphemeralPublicKey, ViewingPublicKey},
 };
 
@@ -81,10 +81,13 @@ impl AccountManager {
 
                     (State::Private(pre), mask)
                 }
+
                 PrivacyPreservingAccount::PrivateForeign { npk, vpk } => {
+                    let account_id = AccountId::private_account_id(&npk, Identifier::default()); //Okay. This is being used a flag currently (Marvin) trying something
                     let acc = nssa_core::account::Account::default();
-                    let auth_acc = AccountWithMetadata::new(acc, false, &npk);
+                    let auth_acc = AccountWithMetadata::new(acc, false, account_id);
                     let pre = AccountPreparedData {
+                        identifier: Identifier::default(), // TODO: ugh. Marvin
                         nsk: None,
                         npk,
                         vpk,
@@ -136,12 +139,13 @@ impl AccountManager {
             .filter_map(|state| match state {
                 State::Private(pre) => {
                     let eph_holder = EphemeralKeyHolder::new(&pre.npk);
+                    let epk = eph_holder.generate_ephemeral_public_key();
 
                     Some(PrivateAccountKeys {
                         npk: pre.npk.clone(),
                         ssk: eph_holder.calculate_shared_secret_sender(&pre.vpk),
                         vpk: pre.vpk.clone(),
-                        epk: eph_holder.generate_ephemeral_public_key(),
+                        epk,
                     })
                 }
                 State::Public { .. } => None,
@@ -149,6 +153,27 @@ impl AccountManager {
             .collect()
     }
 
+    pub fn private_account_identifiers(
+        &self,
+        private_account_keys: &Vec<PrivateAccountKeys>,
+    ) -> Vec<Identifier> {
+        self.states
+            .iter()
+            .zip(private_account_keys)
+            .filter_map(|(state, key)| match state {
+                State::Private(pre) => {
+                    if pre.identifier == Identifier::default() {
+                        // Some(Identifier::default()) ATA works here ATA issue (Marvin)
+                        Some(Identifier::private_identifier(&key.epk, 0)) //TODO: currently using a placeholder index (Marvin)
+                    } else {
+                        Some(pre.identifier)
+                    }
+                }
+                State::Public { .. } => None,
+            })
+            .collect()
+    }
+
     pub fn private_account_auth(&self) -> Vec<NullifierSecretKey> {
         self.states
             .iter()
@@ -191,6 +216,7 @@ impl AccountManager {
 }
 
 struct AccountPreparedData {
+    identifier: Identifier,
     nsk: Option<NullifierSecretKey>,
     npk: NullifierPublicKey,
     vpk: ViewingPublicKey,
@@ -208,6 +234,7 @@ async fn private_acc_preparation(
 
     let from_keys = from_bundle.key_chain;
     let from_acc = from_bundle.account;
+    let from_identifier = from_bundle.identifier;
 
     let nsk = from_keys.private_key_holder.nullifier_secret_key;
 
@@ -222,9 +249,10 @@ async fn private_acc_preparation(
 
     // TODO: Technically we could allow unauthorized owned accounts, but currently we don't have
     // support from that in the wallet.
-    let sender_pre = AccountWithMetadata::new(from_acc.clone(), true, &from_npk);
+    let sender_pre = AccountWithMetadata::new(from_acc.clone(), true, account_id);
 
     Ok(AccountPreparedData {
+        identifier: from_identifier,
         nsk: Some(nsk),
         npk: from_npk,
         vpk: from_vpk,