chore: green light for bn254_blackbox_solver audit

acvm-repo/bn254_blackbox_solver/src/embedded_curve_ops.rs

@@ -1,4 +1,3 @@
-// TODO(https://github.com/noir-lang/noir/issues/4932): rename this file to something more generic
 use ark_ec::AffineRepr;
 use ark_ff::MontConfig;
 use num_bigint::BigUint;
@@ -9,6 +8,19 @@ use acir::BlackBoxFunc;
 
 use crate::BlackBoxResolutionError;
 
+/// Converts a field element to u128, returning an error if it doesn't fit.
+fn field_to_u128_limb(
+    limb: &FieldElement,
+    func: BlackBoxFunc,
+) -> Result<u128, BlackBoxResolutionError> {
+    limb.try_into_u128().ok_or_else(|| {
+        BlackBoxResolutionError::Failed(
+            func,
+            format!("Limb {} is not less than 2^128", limb.to_hex()),
+        )
+    })
+}
+
 /// Performs multi scalar multiplication of points with scalars.
 pub fn multi_scalar_mul(
     points: &[FieldElement],
@@ -33,19 +45,11 @@ pub fn multi_scalar_mul(
             create_point(points[i], points[i + 1], points[i + 2] == FieldElement::from(1_u128))
                 .map_err(|e| BlackBoxResolutionError::Failed(BlackBoxFunc::MultiScalarMul, e))?;
 
-        let scalar_low: u128 = scalars_lo[i / 3].try_into_u128().ok_or_else(|| {
-            BlackBoxResolutionError::Failed(
-                BlackBoxFunc::MultiScalarMul,
-                format!("Limb {} is not less than 2^128", scalars_lo[i].to_hex()),
-            )
-        })?;
+        let scalar_low: u128 =
+            field_to_u128_limb(&scalars_lo[i / 3], BlackBoxFunc::MultiScalarMul)?;
 
-        let scalar_high: u128 = scalars_hi[i / 3].try_into_u128().ok_or_else(|| {
-            BlackBoxResolutionError::Failed(
-                BlackBoxFunc::MultiScalarMul,
-                format!("Limb {} is not less than 2^128", scalars_hi[i].to_hex()),
-            )
-        })?;
+        let scalar_high: u128 =
+            field_to_u128_limb(&scalars_hi[i / 3], BlackBoxFunc::MultiScalarMul)?;
 
         let mut bytes = scalar_high.to_be_bytes().to_vec();
         bytes.extend_from_slice(&scalar_low.to_be_bytes());

acvm-repo/bn254_blackbox_solver/src/lib.rs

@@ -5,13 +5,12 @@ use acvm_blackbox_solver::{BlackBoxFunctionSolver, BlackBoxResolutionError};
 mod embedded_curve_ops;
 mod generator;
 mod poseidon2;
+mod poseidon2_constants;
 
 pub use embedded_curve_ops::{embedded_curve_add, multi_scalar_mul};
 pub use generator::generators::derive_generators;
-pub use poseidon2::{
-    POSEIDON2_CONFIG, Poseidon2Config, Poseidon2Sponge, field_from_hex, poseidon_hash,
-    poseidon2_permutation,
-};
+pub use poseidon2::{Poseidon2Sponge, poseidon_hash, poseidon2_permutation};
+pub use poseidon2_constants::{POSEIDON2_CONFIG, Poseidon2Config, field_from_hex};
 
 // Temporary hack, this ensure that we always use a bn254 field here
 // without polluting the feature flags of the `acir_field` crate.