feat: Add Keccak Hash function

acvm/Cargo.toml

@@ -18,6 +18,7 @@ stdlib.workspace = true
 
 blake2 = "0.9.1"
 sha2 = "0.9.3"
+sha3 = "0.9.1"
 crc32fast = "1.3.2"
 k256 = { version = "0.7.2", features = [
     "ecdsa",

acvm/src/pwg/hash.rs

@@ -1,6 +1,7 @@
 use acir::{circuit::opcodes::BlackBoxFuncCall, native_types::Witness, FieldElement};
 use blake2::{Blake2s, Digest};
 use sha2::Sha256;
+use sha3::Keccak256;
 use std::collections::BTreeMap;
 
 use crate::{OpcodeResolution, OpcodeResolutionError};
@@ -41,6 +42,23 @@ pub fn sha256(
     Ok(OpcodeResolution::Solved)
 }
 
+pub fn keccak256(
+    initial_witness: &mut BTreeMap<Witness, FieldElement>,
+    func_call: &BlackBoxFuncCall,
+) -> Result<OpcodeResolution, OpcodeResolutionError> {
+    let hash = generic_hash_256::<Keccak256>(initial_witness, func_call)?;
+
+    for (output_witness, value) in func_call.outputs.iter().zip(hash.iter()) {
+        insert_value(
+            output_witness,
+            FieldElement::from_be_bytes_reduce(&[*value]),
+            initial_witness,
+        )?;
+    }
+
+    Ok(OpcodeResolution::Solved)
+}
+
 pub fn hash_to_field_128_security(
     initial_witness: &mut BTreeMap<Witness, FieldElement>,
     func_call: &BlackBoxFuncCall,