diff --git a/crates/nargo_cli/src/cli/fs/keys.rs b/crates/nargo_cli/src/cli/fs/keys.rs
index 7890f68a9b4..bbb84876913 100644
--- a/crates/nargo_cli/src/cli/fs/keys.rs
+++ b/crates/nargo_cli/src/cli/fs/keys.rs
@@ -1,9 +1,9 @@
-use super::{create_named_dir, load_hex_data, write_to_file};
+use super::{create_named_dir, load_hex_data, program::checksum_acir, write_to_file};
 use crate::{
     constants::{ACIR_CHECKSUM, PK_EXT, VK_EXT},
     errors::CliError,
 };
-use acvm::{acir::circuit::Circuit, hash_constraint_system};
+use acvm::acir::circuit::Circuit;
 use std::path::{Path, PathBuf};
 
 pub(crate) fn save_key_to_dir<P: AsRef<Path>>(
@@ -30,11 +30,10 @@ pub(crate) fn fetch_pk_and_vk<P: AsRef<Path>>(
 ) -> Result<(Vec<u8>, Vec<u8>), CliError> {
     let acir_hash_path = circuit_build_path.as_ref().with_extension(ACIR_CHECKSUM);
 
-    let expected_acir_hash = load_hex_data(acir_hash_path.clone())?;
+    let expected_acir_checksum = load_hex_data(acir_hash_path.clone())?;
+    let new_acir_checksum = checksum_acir(circuit);
 
-    let new_acir_hash = hash_constraint_system(circuit);
-
-    if new_acir_hash[..] != expected_acir_hash {
+    if new_acir_checksum[..] != expected_acir_checksum {
         return Err(CliError::MismatchedAcir(acir_hash_path));
     }
 
@@ -64,7 +63,7 @@ mod tests {
     use super::fetch_pk_and_vk;
     use crate::cli::fs::{
         keys::save_key_to_dir,
-        program::{hash_acir, save_acir_hash_to_dir},
+        program::{checksum_acir, save_acir_checksum_to_dir},
     };
     use acvm::acir::circuit::Circuit;
     use tempdir::TempDir;
@@ -81,7 +80,7 @@ mod tests {
         save_key_to_dir(&pk, circuit_name, &circuit_build_path, true).unwrap();
         save_key_to_dir(&vk, circuit_name, &circuit_build_path, false).unwrap();
 
-        save_acir_hash_to_dir(hash_acir(&circuit), circuit_name, &circuit_build_path);
+        save_acir_checksum_to_dir(checksum_acir(&circuit), circuit_name, &circuit_build_path);
         circuit_build_path.push(circuit_name);
 
         let loaded_keys = fetch_pk_and_vk(&circuit, circuit_build_path, true, true).unwrap();
diff --git a/crates/nargo_cli/src/cli/fs/program.rs b/crates/nargo_cli/src/cli/fs/program.rs
index 447be9a8f4f..f327c81f609 100644
--- a/crates/nargo_cli/src/cli/fs/program.rs
+++ b/crates/nargo_cli/src/cli/fs/program.rs
@@ -1,6 +1,6 @@
 use std::path::{Path, PathBuf};
 
-use acvm::{acir::circuit::Circuit, hash_constraint_system};
+use acvm::{acir::circuit::Circuit, checksum_constraint_system};
 use noirc_driver::{CompiledContract, CompiledProgram};
 
 use crate::{constants::ACIR_CHECKSUM, errors::CliError};
@@ -34,16 +34,16 @@ fn save_build_artifact_to_file<P: AsRef<Path>, T: ?Sized + serde::Serialize>(
     circuit_path
 }
 
-pub(crate) fn hash_acir(circuit: &Circuit) -> [u8; 32] {
-    hash_constraint_system(circuit)
+pub(crate) fn checksum_acir(circuit: &Circuit) -> [u8; 4] {
+    checksum_constraint_system(circuit).to_be_bytes()
 }
-pub(crate) fn save_acir_hash_to_dir<P: AsRef<Path>>(
-    acir_hash: [u8; 32],
+pub(crate) fn save_acir_checksum_to_dir<P: AsRef<Path>>(
+    acir_checksum: [u8; 4],
     hash_name: &str,
     hash_dir: P,
 ) -> PathBuf {
     let hash_path = hash_dir.as_ref().join(hash_name).with_extension(ACIR_CHECKSUM);
-    write_to_file(hex::encode(acir_hash).as_bytes(), &hash_path);
+    write_to_file(hex::encode(acir_checksum).as_bytes(), &hash_path);
 
     hash_path
 }
diff --git a/crates/nargo_cli/src/cli/preprocess_cmd.rs b/crates/nargo_cli/src/cli/preprocess_cmd.rs
index eab66a91122..05f6edd60a4 100644
--- a/crates/nargo_cli/src/cli/preprocess_cmd.rs
+++ b/crates/nargo_cli/src/cli/preprocess_cmd.rs
@@ -8,7 +8,7 @@ use crate::{constants::TARGET_DIR, errors::CliError};
 
 use super::fs::{
     keys::save_key_to_dir,
-    program::{hash_acir, read_program_from_file, save_acir_hash_to_dir},
+    program::{checksum_acir, read_program_from_file, save_acir_checksum_to_dir},
 };
 use super::NargoConfig;
 
@@ -38,16 +38,16 @@ pub(crate) fn run(args: PreprocessCommand, config: NargoConfig) -> Result<(), Cl
 pub(crate) struct PreprocessedData {
     pub(crate) proving_key: Vec<u8>,
     pub(crate) verification_key: Vec<u8>,
-    pub(crate) program_hash: [u8; 32],
+    pub(crate) program_checksum: [u8; 4],
 }
 
 impl From<&Circuit> for PreprocessedData {
     fn from(circuit: &Circuit) -> Self {
         let backend = crate::backends::ConcreteBackend;
         let (proving_key, verification_key) = backend.preprocess(circuit);
-        let program_hash = hash_acir(circuit);
+        let program_checksum = checksum_acir(circuit);
 
-        PreprocessedData { proving_key, verification_key, program_hash }
+        PreprocessedData { proving_key, verification_key, program_checksum }
     }
 }
 
@@ -58,7 +58,7 @@ pub(crate) fn save_preprocess_data<P: AsRef<Path>>(
 ) -> Result<(PathBuf, PathBuf), CliError> {
     // Save a checksum of the circuit to compare against during proving and verification.
     // If hash doesn't match then the circuit has been updated and keys are stale.
-    save_acir_hash_to_dir(data.program_hash, key_name, &preprocess_dir);
+    save_acir_checksum_to_dir(data.program_checksum, key_name, &preprocess_dir);
 
     let pk_path = save_key_to_dir(&data.proving_key, key_name, &preprocess_dir, true)?;
     let vk_path = save_key_to_dir(&data.verification_key, key_name, preprocess_dir, false)?;