From a007fe4881683070152775394eec74af2cbea16d Mon Sep 17 00:00:00 2001
From: Tom French <tom@tomfren.ch>
Date: Tue, 4 Apr 2023 18:39:58 +0100
Subject: [PATCH] chore: use faster hash function for checking keys

---
 crates/nargo_cli/src/cli/fs/keys.rs        | 13 ++++++-------
 crates/nargo_cli/src/cli/fs/program.rs     |  8 ++++----
 crates/nargo_cli/src/cli/preprocess_cmd.rs |  6 +++---
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/crates/nargo_cli/src/cli/fs/keys.rs b/crates/nargo_cli/src/cli/fs/keys.rs
index 87276c2ded3..52409eee96c 100644
--- a/crates/nargo_cli/src/cli/fs/keys.rs
+++ b/crates/nargo_cli/src/cli/fs/keys.rs
@@ -3,7 +3,7 @@ use crate::{
     constants::{ACIR_CHECKSUM, PK_EXT, VK_EXT},
     errors::CliError,
 };
-use acvm::{acir::circuit::Circuit, hash_constraint_system};
+use acvm::{acir::circuit::Circuit, checksum_constraint_system};
 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_constraint_system(circuit).to_be_bytes();
 
-    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));
     }
 
@@ -62,7 +61,7 @@ pub(crate) fn fetch_pk_and_vk<P: AsRef<Path>>(
 #[cfg(test)]
 mod tests {
     use super::fetch_pk_and_vk;
-    use crate::cli::fs::{keys::save_key_to_dir, program::save_acir_hash_to_dir};
+    use crate::cli::fs::{keys::save_key_to_dir, program::save_acir_checksum_to_dir};
     use acvm::acir::circuit::Circuit;
     use tempdir::TempDir;
 
@@ -78,7 +77,7 @@ 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(&circuit, circuit_name, &circuit_build_path);
+        save_acir_checksum_to_dir(&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 b50ba4665b7..f78a4f5e378 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};
@@ -34,14 +34,14 @@ fn save_build_artifact_to_file<P: AsRef<Path>, T: ?Sized + serde::Serialize>(
     circuit_path
 }
 
-pub(crate) fn save_acir_hash_to_dir<P: AsRef<Path>>(
+pub(crate) fn save_acir_checksum_to_dir<P: AsRef<Path>>(
     circuit: &Circuit,
     hash_name: &str,
     hash_dir: P,
 ) -> PathBuf {
-    let acir_hash = hash_constraint_system(circuit);
+    let acir_checksum = checksum_constraint_system(circuit);
     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.to_be_bytes()).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 9023fffe1c6..a835a8ad716 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::{read_program_from_file, save_acir_hash_to_dir},
+    program::{read_program_from_file, save_acir_checksum_to_dir},
 };
 use super::NargoConfig;
 
@@ -38,8 +38,8 @@ pub(crate) fn preprocess_with_path<P: AsRef<Path>>(
     let (proving_key, verification_key) = backend.preprocess(circuit);
 
     // 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(circuit, key_name, &preprocess_dir);
+    // If the checksums don't match then the circuit has been updated and keys are stale.
+    save_acir_checksum_to_dir(circuit, key_name, &preprocess_dir);
 
     let pk_path = save_key_to_dir(&proving_key, key_name, &preprocess_dir, true)?;
     let vk_path = save_key_to_dir(&verification_key, key_name, preprocess_dir, false)?;