diff --git a/risc0-selective-privacy-poc/core/src/account.rs b/risc0-selective-privacy-poc/core/src/account.rs
index 1c0b67b..f76e82c 100644
--- a/risc0-selective-privacy-poc/core/src/account.rs
+++ b/risc0-selective-privacy-poc/core/src/account.rs
@@ -9,6 +9,7 @@ pub type Nullifier = [u32; 8];
 pub type Address = [u32; 8];
 pub type Nonce = [u32; 8];
 pub type Key = [u32; 8];
+pub type AuthenticationPath = [[u32; 8]; 32];
 
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
 pub struct Account {
@@ -47,7 +48,11 @@ pub fn hash(bytes: &[u32]) -> [u32; 8] {
 }
 
 /// Dummy implementation
-pub fn is_in_commitment_tree(_commitment: Commitment, _tree_root: [u32; 8]) -> bool {
+pub fn is_in_tree(
+    _commitment: Commitment,
+    _auth_path: &AuthenticationPath,
+    _tree_root: [u32; 8],
+) -> bool {
     true
 }
 
@@ -58,3 +63,11 @@ pub fn compute_nullifier(commitment: &Commitment, private_key: &Key) -> Nullifie
     bytes_to_hash[1..].copy_from_slice(private_key);
     hash(&bytes_to_hash)
 }
+
+pub fn bytes_to_words(bytes: [u8; 32]) -> [u32; 8] {
+    let mut words = [0; 8];
+    for (i, chunk) in bytes.chunks(4).enumerate() {
+        words[i] = u32::from_le_bytes(chunk.try_into().unwrap());
+    }
+    words
+}
diff --git a/risc0-selective-privacy-poc/core/src/input.rs b/risc0-selective-privacy-poc/core/src/input.rs
index 9c303f0..fc7930f 100644
--- a/risc0-selective-privacy-poc/core/src/input.rs
+++ b/risc0-selective-privacy-poc/core/src/input.rs
@@ -1,4 +1,4 @@
-use crate::account::Key;
+use crate::account::{AuthenticationPath, Key};
 use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize)]
@@ -6,5 +6,5 @@ pub enum InputVisibiility {
     // A public account
     Public,
     // A private account
-    Private(Option<Key>),
+    Private(Option<(Key, AuthenticationPath)>),
 }
diff --git a/risc0-selective-privacy-poc/core/src/lib.rs b/risc0-selective-privacy-poc/core/src/lib.rs
index 873929a..2b84523 100644
--- a/risc0-selective-privacy-poc/core/src/lib.rs
+++ b/risc0-selective-privacy-poc/core/src/lib.rs
@@ -1,3 +1,5 @@
 pub mod account;
 pub mod input;
 
+
+
diff --git a/risc0-selective-privacy-poc/outer_methods/guest/src/bin/outer.rs b/risc0-selective-privacy-poc/outer_methods/guest/src/bin/outer.rs
index c64a3f6..bcfa30e 100644
--- a/risc0-selective-privacy-poc/outer_methods/guest/src/bin/outer.rs
+++ b/risc0-selective-privacy-poc/outer_methods/guest/src/bin/outer.rs
@@ -1,6 +1,6 @@
 use risc0_zkvm::{guest::env, serde::to_vec};
 use toy_example_core::{
-    account::{compute_nullifier, hash, is_in_commitment_tree, Account, Nonce},
+    account::{compute_nullifier, hash, is_in_tree, Account, Nonce},
     input::InputVisibiility,
 };
 
@@ -49,14 +49,14 @@ fn main() {
     let mut nullifiers = Vec::new();
     for (visibility, input_account) in input_visibilities.iter().zip(inputs.iter()) {
         match visibility {
-            InputVisibiility::Private(Some(private_key)) => {
+            InputVisibiility::Private(Some((private_key, auth_path))) => {
                 // Prove ownership of input accounts by proving
                 // knowledge of the pre-image of their addresses.
                 assert_eq!(hash(private_key), input_account.address);
                 // Check the input account was created by a previous transaction
                 // by checking it belongs to the commitments tree.
                 let commitment = input_account.commitment();
-                assert!(is_in_commitment_tree(commitment, commitment_tree_root));
+                assert!(is_in_tree(commitment, auth_path, commitment_tree_root));
                 // Compute nullifier to nullify this private input account.
                 let nullifier = compute_nullifier(&commitment, private_key);
                 nullifiers.push(nullifier);
diff --git a/risc0-selective-privacy-poc/src/private_execution.rs b/risc0-selective-privacy-poc/src/private_execution.rs
index c41c1a4..2d476f2 100644
--- a/risc0-selective-privacy-poc/src/private_execution.rs
+++ b/risc0-selective-privacy-poc/src/private_execution.rs
@@ -1,14 +1,13 @@
 use outer_methods::{OUTER_ELF, OUTER_ID};
 use rand::{rngs::OsRng, Rng};
 use risc0_zkvm::{default_prover, ExecutorEnv, Receipt};
+use sparse_merkle_tree::SparseMerkleTree;
 use toy_example_core::{
-    account::{Account, Address, Commitment, Nonce, Nullifier},
+    account::{bytes_to_words, Account, Address, Commitment, Nonce, Nullifier},
     input::InputVisibiility,
 };
 use transfer_methods::{TRANSFER_ELF, TRANSFER_ID};
 
-const COMMITMENT_TREE_ROOT: [u32; 8] = [0xdd, 0xee, 0xaa, 0xdd, 0xbb, 0xee, 0xee, 0xff];
-
 pub fn new_random_nonce() -> Nonce {
     let mut rng = OsRng;
     std::array::from_fn(|_| rng.gen())
@@ -32,6 +31,9 @@ fn run_private_execution_of_transfer_program() {
         account.balance = 150;
         account
     };
+    let commitment_tree = SparseMerkleTree::new([sender.commitment()].into_iter().collect());
+    let root = bytes_to_words(commitment_tree.root());
+    let auth_path = commitment_tree.get_authentication_path_for_value(sender.commitment());
 
     let balance_to_move: u128 = 3;
 
@@ -44,7 +46,7 @@ fn run_private_execution_of_transfer_program() {
     let (inner_receipt, inputs_outputs) = prove_inner(&sender, &receiver, balance_to_move);
 
     let visibilities = vec![
-        InputVisibiility::Private(Some(sender_private_key)),
+        InputVisibiility::Private(Some((sender_private_key, [[0; 8]; 32]))),
         InputVisibiility::Private(None),
     ];
 
@@ -63,7 +65,7 @@ fn run_private_execution_of_transfer_program() {
     env_builder.write(&inputs_outputs).unwrap();
     env_builder.write(&visibilities).unwrap();
     env_builder.write(&output_nonces).unwrap();
-    env_builder.write(&COMMITMENT_TREE_ROOT).unwrap();
+    env_builder.write(&root).unwrap();
     env_builder.write(&TRANSFER_ID).unwrap();
     let env = env_builder.build().unwrap();