diff --git a/Cargo.lock b/Cargo.lock
index d6a7b766..ea0dca84 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4601,6 +4601,7 @@ name = "program_deployment"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "hex",
  "nssa",
  "nssa_core",
  "tokio",
diff --git a/examples/program_deployment/Cargo.toml b/examples/program_deployment/Cargo.toml
index 2199fe21..81497226 100644
--- a/examples/program_deployment/Cargo.toml
+++ b/examples/program_deployment/Cargo.toml
@@ -11,3 +11,4 @@ wallet.workspace = true
 
 tokio = { workspace = true, features = ["macros"] }
 clap.workspace = true
+hex.workspace = true
diff --git a/examples/program_deployment/methods/guest/src/bin/attestation.rs b/examples/program_deployment/methods/guest/src/bin/attestation.rs
new file mode 100644
index 00000000..2dd77d57
--- /dev/null
+++ b/examples/program_deployment/methods/guest/src/bin/attestation.rs
@@ -0,0 +1,509 @@
+use nssa_core::{
+    account::{Account, AccountId, AccountWithMetadata, Data},
+    program::{
+        AccountPostState, ProgramInput, read_nssa_inputs, write_nssa_outputs,
+    },
+};
+
+// Attestation registry program.
+//
+// Any account holder can create attestations about any subject, identified by
+// a 32-byte key, with an arbitrary-length value. Only the original creator can
+// update or revoke their attestation.
+//
+// Data layout (stored in the attestation account's `data` field):
+//   Bytes  0..32  : creator  (AccountId, 32 bytes)
+//   Bytes  32..64 : subject  (AccountId, 32 bytes)
+//   Bytes  64..96 : key      ([u8; 32], 32 bytes)
+//   Byte   96     : revoked  (bool, 0 = active, 1 = revoked)
+//   Bytes  97..   : value    (variable length)
+//
+// Instructions:
+//   0x00  Attest  — payload: subject (32) || key (32) || value (var)
+//                   accounts: [creator (authorized), attestation_account]
+//   0x01  Revoke  — payload: (none)
+//                   accounts: [creator (authorized), attestation_account]
+
+const ATTESTATION_HEADER_SIZE: usize = 97; // 32 + 32 + 32 + 1
+
+struct Attestation {
+    creator: AccountId,
+    subject: AccountId,
+    key: [u8; 32],
+    revoked: bool,
+    value: Vec<u8>,
+}
+
+impl Attestation {
+    fn into_data(self) -> Data {
+        let mut bytes = Vec::<u8>::new();
+        bytes.extend_from_slice(&self.creator.to_bytes());
+        bytes.extend_from_slice(&self.subject.to_bytes());
+        bytes.extend_from_slice(&self.key);
+        bytes.push(self.revoked as u8);
+        bytes.extend_from_slice(&self.value);
+
+        Data::try_from(bytes).expect("Attestation data must fit within the allowed limits")
+    }
+
+    fn parse(data: &Data) -> Option<Self> {
+        let data = Vec::<u8>::from(data.clone());
+
+        if data.len() < ATTESTATION_HEADER_SIZE {
+            return None;
+        }
+
+        let creator = AccountId::new(
+            data[0..32]
+                .try_into()
+                .expect("Creator must be 32 bytes"),
+        );
+        let subject = AccountId::new(
+            data[32..64]
+                .try_into()
+                .expect("Subject must be 32 bytes"),
+        );
+        let key: [u8; 32] = data[64..96]
+            .try_into()
+            .expect("Key must be 32 bytes");
+        let revoked = data[96] != 0;
+        let value = data[97..].to_vec();
+
+        Some(Self {
+            creator,
+            subject,
+            key,
+            revoked,
+            value,
+        })
+    }
+}
+
+fn attest(pre_states: &[AccountWithMetadata], payload: &[u8]) -> Vec<AccountPostState> {
+    if pre_states.len() != 2 {
+        panic!("Attest requires exactly 2 accounts");
+    }
+
+    let creator_account = &pre_states[0];
+    let attestation_account = &pre_states[1];
+
+    if !creator_account.is_authorized {
+        panic!("Missing required authorization for creator");
+    }
+
+    if payload.len() < 64 {
+        panic!("Attest payload must contain at least subject (32) and key (32)");
+    }
+
+    let subject = AccountId::new(
+        payload[0..32]
+            .try_into()
+            .expect("Subject must be 32 bytes"),
+    );
+    let key: [u8; 32] = payload[32..64]
+        .try_into()
+        .expect("Key must be 32 bytes");
+    let value = payload[64..].to_vec();
+
+    let attestation_post = if attestation_account.account == Account::default() {
+        // Creating a new attestation
+        let attestation = Attestation {
+            creator: creator_account.account_id,
+            subject,
+            key,
+            revoked: false,
+            value,
+        };
+
+        let mut account = attestation_account.account.clone();
+        account.data = attestation.into_data();
+        AccountPostState::new_claimed(account)
+    } else {
+        // Updating an existing attestation
+        let mut existing = Attestation::parse(&attestation_account.account.data)
+            .expect("Invalid existing attestation data");
+
+        assert_eq!(
+            existing.creator, creator_account.account_id,
+            "Only the original creator can update an attestation"
+        );
+        assert!(
+            !existing.revoked,
+            "Cannot update a revoked attestation"
+        );
+
+        existing.value = value;
+
+        let mut account = attestation_account.account.clone();
+        account.data = existing.into_data();
+        AccountPostState::new(account)
+    };
+
+    let creator_post = AccountPostState::new(creator_account.account.clone());
+
+    vec![creator_post, attestation_post]
+}
+
+fn revoke(pre_states: &[AccountWithMetadata]) -> Vec<AccountPostState> {
+    if pre_states.len() != 2 {
+        panic!("Revoke requires exactly 2 accounts");
+    }
+
+    let creator_account = &pre_states[0];
+    let attestation_account = &pre_states[1];
+
+    if !creator_account.is_authorized {
+        panic!("Missing required authorization for creator");
+    }
+
+    if attestation_account.account == Account::default() {
+        panic!("Cannot revoke a non-existent attestation");
+    }
+
+    let mut existing = Attestation::parse(&attestation_account.account.data)
+        .expect("Invalid existing attestation data");
+
+    assert_eq!(
+        existing.creator, creator_account.account_id,
+        "Only the original creator can revoke an attestation"
+    );
+    assert!(
+        !existing.revoked,
+        "Attestation is already revoked"
+    );
+
+    existing.revoked = true;
+
+    let mut account = attestation_account.account.clone();
+    account.data = existing.into_data();
+
+    let creator_post = AccountPostState::new(creator_account.account.clone());
+    let attestation_post = AccountPostState::new(account);
+
+    vec![creator_post, attestation_post]
+}
+
+type Instruction = Vec<u8>;
+
+fn main() {
+    let (
+        ProgramInput {
+            pre_states,
+            instruction,
+        },
+        instruction_data,
+    ) = read_nssa_inputs::<Instruction>();
+
+    let post_states = match instruction[0] {
+        0 => attest(&pre_states, &instruction[1..]),
+        1 => revoke(&pre_states),
+        _ => panic!("Invalid instruction opcode"),
+    };
+
+    write_nssa_outputs(instruction_data, pre_states, post_states);
+}
+
+#[cfg(test)]
+mod tests {
+    use nssa_core::account::{Account, AccountId, AccountWithMetadata, Data};
+
+    use crate::{ATTESTATION_HEADER_SIZE, Attestation, attest, revoke};
+
+    fn creator_id() -> AccountId {
+        AccountId::new([1; 32])
+    }
+
+    fn subject_id() -> AccountId {
+        AccountId::new([2; 32])
+    }
+
+    fn attestation_key() -> [u8; 32] {
+        [3; 32]
+    }
+
+    fn creator_account(is_authorized: bool) -> AccountWithMetadata {
+        AccountWithMetadata {
+            account: Account {
+                program_owner: [5u32; 8],
+                balance: 0,
+                data: Data::default(),
+                nonce: 0,
+            },
+            is_authorized,
+            account_id: creator_id(),
+        }
+    }
+
+    fn uninit_attestation_account() -> AccountWithMetadata {
+        AccountWithMetadata {
+            account: Account::default(),
+            is_authorized: false,
+            account_id: AccountId::new([10; 32]),
+        }
+    }
+
+    fn existing_attestation_account(revoked: bool, value: &[u8]) -> AccountWithMetadata {
+        let attestation = Attestation {
+            creator: creator_id(),
+            subject: subject_id(),
+            key: attestation_key(),
+            revoked,
+            value: value.to_vec(),
+        };
+        AccountWithMetadata {
+            account: Account {
+                program_owner: [5u32; 8],
+                balance: 0,
+                data: attestation.into_data(),
+                nonce: 0,
+            },
+            is_authorized: false,
+            account_id: AccountId::new([10; 32]),
+        }
+    }
+
+    fn build_attest_payload(subject: &AccountId, key: &[u8; 32], value: &[u8]) -> Vec<u8> {
+        let mut payload = Vec::new();
+        payload.extend_from_slice(subject.value());
+        payload.extend_from_slice(key);
+        payload.extend_from_slice(value);
+        payload
+    }
+
+    #[test]
+    fn test_attestation_serialize_deserialize() {
+        let original = Attestation {
+            creator: creator_id(),
+            subject: subject_id(),
+            key: attestation_key(),
+            revoked: false,
+            value: b"hello world".to_vec(),
+        };
+
+        let data = original.into_data();
+        let parsed = Attestation::parse(&data).expect("Should parse successfully");
+
+        assert_eq!(parsed.creator, creator_id());
+        assert_eq!(parsed.subject, subject_id());
+        assert_eq!(parsed.key, attestation_key());
+        assert!(!parsed.revoked);
+        assert_eq!(parsed.value, b"hello world");
+    }
+
+    #[test]
+    fn test_attestation_parse_invalid_length() {
+        let short_data = Data::try_from(vec![0u8; ATTESTATION_HEADER_SIZE - 1]).unwrap();
+        assert!(Attestation::parse(&short_data).is_none());
+    }
+
+    #[test]
+    fn test_attestation_parse_empty() {
+        let empty_data = Data::default();
+        assert!(Attestation::parse(&empty_data).is_none());
+    }
+
+    #[test]
+    fn test_attest_create_new() {
+        let pre_states = vec![creator_account(true), uninit_attestation_account()];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"test value");
+
+        let post_states = attest(&pre_states, &payload);
+        assert_eq!(post_states.len(), 2);
+
+        // Creator account should be unchanged
+        assert_eq!(*post_states[0].account(), pre_states[0].account);
+        assert!(!post_states[0].requires_claim());
+
+        // Attestation account should be claimed with new data
+        assert!(post_states[1].requires_claim());
+        let parsed = Attestation::parse(&post_states[1].account().data)
+            .expect("Should parse attestation");
+        assert_eq!(parsed.creator, creator_id());
+        assert_eq!(parsed.subject, subject_id());
+        assert_eq!(parsed.key, attestation_key());
+        assert!(!parsed.revoked);
+        assert_eq!(parsed.value, b"test value");
+    }
+
+    #[test]
+    fn test_attest_update_existing() {
+        let pre_states = vec![
+            creator_account(true),
+            existing_attestation_account(false, b"old value"),
+        ];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"new value");
+
+        let post_states = attest(&pre_states, &payload);
+        assert_eq!(post_states.len(), 2);
+
+        assert!(!post_states[1].requires_claim());
+        let parsed = Attestation::parse(&post_states[1].account().data)
+            .expect("Should parse attestation");
+        assert_eq!(parsed.value, b"new value");
+        assert!(!parsed.revoked);
+    }
+
+    #[test]
+    #[should_panic(expected = "Missing required authorization for creator")]
+    fn test_attest_missing_authorization() {
+        let pre_states = vec![creator_account(false), uninit_attestation_account()];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"test");
+
+        attest(&pre_states, &payload);
+    }
+
+    #[test]
+    #[should_panic(expected = "Only the original creator can update an attestation")]
+    fn test_attest_update_wrong_creator() {
+        let different_creator = AccountWithMetadata {
+            account: Account {
+                program_owner: [5u32; 8],
+                balance: 0,
+                data: Data::default(),
+                nonce: 0,
+            },
+            is_authorized: true,
+            account_id: AccountId::new([99; 32]),
+        };
+        let pre_states = vec![
+            different_creator,
+            existing_attestation_account(false, b"old"),
+        ];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"new");
+
+        attest(&pre_states, &payload);
+    }
+
+    #[test]
+    #[should_panic(expected = "Cannot update a revoked attestation")]
+    fn test_attest_update_revoked() {
+        let pre_states = vec![
+            creator_account(true),
+            existing_attestation_account(true, b"old"),
+        ];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"new");
+
+        attest(&pre_states, &payload);
+    }
+
+    #[test]
+    #[should_panic(expected = "Attest requires exactly 2 accounts")]
+    fn test_attest_wrong_account_count() {
+        let pre_states = vec![creator_account(true)];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"test");
+
+        attest(&pre_states, &payload);
+    }
+
+    #[test]
+    #[should_panic(expected = "Attest payload must contain at least subject (32) and key (32)")]
+    fn test_attest_payload_too_short() {
+        let pre_states = vec![creator_account(true), uninit_attestation_account()];
+
+        attest(&pre_states, &[0u8; 63]);
+    }
+
+    #[test]
+    fn test_revoke_success() {
+        let pre_states = vec![
+            creator_account(true),
+            existing_attestation_account(false, b"some value"),
+        ];
+
+        let post_states = revoke(&pre_states);
+        assert_eq!(post_states.len(), 2);
+
+        assert_eq!(*post_states[0].account(), pre_states[0].account);
+        assert!(!post_states[0].requires_claim());
+
+        assert!(!post_states[1].requires_claim());
+        let parsed = Attestation::parse(&post_states[1].account().data)
+            .expect("Should parse attestation");
+        assert!(parsed.revoked);
+        assert_eq!(parsed.value, b"some value");
+    }
+
+    #[test]
+    #[should_panic(expected = "Missing required authorization for creator")]
+    fn test_revoke_missing_authorization() {
+        let pre_states = vec![
+            creator_account(false),
+            existing_attestation_account(false, b"val"),
+        ];
+
+        revoke(&pre_states);
+    }
+
+    #[test]
+    #[should_panic(expected = "Cannot revoke a non-existent attestation")]
+    fn test_revoke_nonexistent() {
+        let pre_states = vec![creator_account(true), uninit_attestation_account()];
+
+        revoke(&pre_states);
+    }
+
+    #[test]
+    #[should_panic(expected = "Only the original creator can revoke an attestation")]
+    fn test_revoke_wrong_creator() {
+        let different_creator = AccountWithMetadata {
+            account: Account {
+                program_owner: [5u32; 8],
+                balance: 0,
+                data: Data::default(),
+                nonce: 0,
+            },
+            is_authorized: true,
+            account_id: AccountId::new([99; 32]),
+        };
+        let pre_states = vec![
+            different_creator,
+            existing_attestation_account(false, b"val"),
+        ];
+
+        revoke(&pre_states);
+    }
+
+    #[test]
+    #[should_panic(expected = "Attestation is already revoked")]
+    fn test_revoke_already_revoked() {
+        let pre_states = vec![
+            creator_account(true),
+            existing_attestation_account(true, b"val"),
+        ];
+
+        revoke(&pre_states);
+    }
+
+    #[test]
+    #[should_panic(expected = "Revoke requires exactly 2 accounts")]
+    fn test_revoke_wrong_account_count() {
+        let pre_states = vec![creator_account(true)];
+
+        revoke(&pre_states);
+    }
+
+    #[test]
+    fn test_attest_empty_value() {
+        let pre_states = vec![creator_account(true), uninit_attestation_account()];
+        let payload = build_attest_payload(&subject_id(), &attestation_key(), b"");
+
+        let post_states = attest(&pre_states, &payload);
+
+        let parsed = Attestation::parse(&post_states[1].account().data)
+            .expect("Should parse attestation");
+        assert_eq!(parsed.value, b"");
+    }
+
+    #[test]
+    fn test_attestation_header_size_matches_parse() {
+        let attestation = Attestation {
+            creator: creator_id(),
+            subject: subject_id(),
+            key: attestation_key(),
+            revoked: false,
+            value: vec![],
+        };
+        let data = attestation.into_data();
+        assert_eq!(data.len(), ATTESTATION_HEADER_SIZE);
+    }
+}
diff --git a/examples/program_deployment/src/bin/run_attestation.rs b/examples/program_deployment/src/bin/run_attestation.rs
new file mode 100644
index 00000000..bd2578a9
--- /dev/null
+++ b/examples/program_deployment/src/bin/run_attestation.rs
@@ -0,0 +1,161 @@
+use clap::{Parser, Subcommand};
+use nssa::{
+    AccountId, PublicTransaction,
+    program::Program,
+    public_transaction::{Message, WitnessSet},
+};
+use wallet::WalletCore;
+
+// Before running this example, compile the `attestation.rs` guest program with:
+//
+//   cargo risczero build --manifest-path examples/program_deployment/methods/guest/Cargo.toml
+//
+// Note: you must run the above command from the root of the repository.
+// Note: The compiled binary file is stored in
+// methods/guest/target/riscv32im-risc0-zkvm-elf/docker/attestation.bin
+//
+// Usage:
+//   cargo run --bin run_attestation -- <program_binary_path> <subcommand>
+//
+// Examples:
+//   cargo run --bin run_attestation -- \
+//     methods/guest/target/riscv32im-risc0-zkvm-elf/docker/attestation.bin \
+//     attest <creator_id> <attestation_id> <subject_id> <key_hex> <value_string>
+//
+//   cargo run --bin run_attestation -- \
+//     methods/guest/target/riscv32im-risc0-zkvm-elf/docker/attestation.bin \
+//     revoke <creator_id> <attestation_id>
+
+#[derive(Parser, Debug)]
+struct Cli {
+    /// Path to the attestation program binary
+    program_path: String,
+
+    #[command(subcommand)]
+    command: Command,
+}
+
+#[derive(Subcommand, Debug)]
+enum Command {
+    /// Create or update an attestation
+    Attest {
+        /// Account ID of the creator (must be a self-owned public account)
+        creator_id: String,
+        /// Account ID for the attestation record
+        attestation_id: String,
+        /// Account ID of the subject being attested about
+        subject_id: String,
+        /// 32-byte attestation key as a hex string (64 hex chars)
+        key_hex: String,
+        /// Attestation value as a UTF-8 string
+        value_string: String,
+    },
+    /// Revoke an existing attestation
+    Revoke {
+        /// Account ID of the creator (must be a self-owned public account)
+        creator_id: String,
+        /// Account ID of the attestation record to revoke
+        attestation_id: String,
+    },
+}
+
+#[tokio::main]
+async fn main() {
+    let cli = Cli::parse();
+
+    // Load the program
+    let bytecode: Vec<u8> = std::fs::read(cli.program_path).unwrap();
+    let program = Program::new(bytecode).unwrap();
+
+    // Initialize wallet
+    let wallet_core = WalletCore::from_env().unwrap();
+
+    match cli.command {
+        Command::Attest {
+            creator_id,
+            attestation_id,
+            subject_id,
+            key_hex,
+            value_string,
+        } => {
+            let creator_id: AccountId = creator_id.parse().unwrap();
+            let attestation_id: AccountId = attestation_id.parse().unwrap();
+            let subject_id: AccountId = subject_id.parse().unwrap();
+            let key_bytes: [u8; 32] = hex::decode(&key_hex)
+                .expect("key_hex must be valid hex")
+                .try_into()
+                .expect("key_hex must decode to exactly 32 bytes");
+
+            let signing_key = wallet_core
+                .storage()
+                .user_data
+                .get_pub_account_signing_key(&creator_id)
+                .expect("Creator account should be a self-owned public account");
+
+            let nonces = wallet_core
+                .get_accounts_nonces(vec![creator_id])
+                .await
+                .expect("Node should be reachable to query account data");
+
+            // Build instruction: [0x00 || subject (32) || key (32) || value (var)]
+            let mut instruction: Vec<u8> = Vec::new();
+            instruction.push(0x00);
+            instruction.extend_from_slice(subject_id.value());
+            instruction.extend_from_slice(&key_bytes);
+            instruction.extend_from_slice(value_string.as_bytes());
+
+            let message = Message::try_new(
+                program.id(),
+                vec![creator_id, attestation_id],
+                nonces,
+                instruction,
+            )
+            .unwrap();
+            let witness_set = WitnessSet::for_message(&message, &[signing_key]);
+            let tx = PublicTransaction::new(message, witness_set);
+
+            let _response = wallet_core
+                .sequencer_client
+                .send_tx_public(tx)
+                .await
+                .unwrap();
+        }
+        Command::Revoke {
+            creator_id,
+            attestation_id,
+        } => {
+            let creator_id: AccountId = creator_id.parse().unwrap();
+            let attestation_id: AccountId = attestation_id.parse().unwrap();
+
+            let signing_key = wallet_core
+                .storage()
+                .user_data
+                .get_pub_account_signing_key(&creator_id)
+                .expect("Creator account should be a self-owned public account");
+
+            let nonces = wallet_core
+                .get_accounts_nonces(vec![creator_id])
+                .await
+                .expect("Node should be reachable to query account data");
+
+            // Build instruction: [0x01]
+            let instruction: Vec<u8> = vec![0x01];
+
+            let message = Message::try_new(
+                program.id(),
+                vec![creator_id, attestation_id],
+                nonces,
+                instruction,
+            )
+            .unwrap();
+            let witness_set = WitnessSet::for_message(&message, &[signing_key]);
+            let tx = PublicTransaction::new(message, witness_set);
+
+            let _response = wallet_core
+                .sequencer_client
+                .send_tx_public(tx)
+                .await
+                .unwrap();
+        }
+    }
+}