refactor: secret derivation funcs naming cleanup (#10637)

Author: benesjan

noir-projects/aztec-nr/aztec/src/encrypted_logs/header.nr

@@ -5,7 +5,7 @@ use dep::protocol_types::{
     scalar::Scalar,
 };
 
-use crate::keys::point_to_symmetric_key::point_to_symmetric_key;
+use crate::keys::secret_derivation::derive_aes_secret;
 
 use std::aes128::aes128_encrypt;
 
@@ -22,7 +22,7 @@ impl EncryptedLogHeader {
     where
         T: ToPoint,
     {
-        let full_key = point_to_symmetric_key(secret, pk.to_point());
+        let full_key = derive_aes_secret(secret, pk.to_point());
         let mut sym_key = [0; 16];
         let mut iv = [0; 16];
 

noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr

@@ -14,7 +14,7 @@ use std::{
 
 use crate::{
     encrypted_logs::header::EncryptedLogHeader,
-    keys::point_to_symmetric_key::point_to_symmetric_key,
+    keys::secret_derivation::derive_aes_secret,
     oracle::{
         notes::{get_app_tag_as_sender, increment_app_tagging_secret_index_as_sender},
         random::random,
@@ -208,7 +208,7 @@ pub fn compute_incoming_body_ciphertext<let P: u32>(
     eph_sk: Scalar,
     address_point: AddressPoint,
 ) -> [u8] {
-    let full_key = point_to_symmetric_key(eph_sk, address_point.to_point());
+    let full_key = derive_aes_secret(eph_sk, address_point.to_point());
     let mut sym_key = [0; 16];
     let mut iv = [0; 16];
 

noir-projects/aztec-nr/aztec/src/keys/mod.nr

@@ -1,3 +1,3 @@
 pub mod constants;
 pub mod getters;
-pub mod point_to_symmetric_key;
+pub mod secret_derivation;

noir-projects/aztec-nr/aztec/src/keys/point_to_symmetric_key.nr noir-projects/aztec-nr/aztec/src/keys/secret_derivation.nr

@@ -2,9 +2,7 @@ use crate::utils::point::point_to_bytes;
 use dep::protocol_types::{constants::GENERATOR_INDEX__SYMMETRIC_KEY, point::Point, scalar::Scalar};
 use std::{embedded_curve_ops::multi_scalar_mul, hash::sha256};
 
-// TODO(#5726): This function is called deriveAESSecret in TS. I don't like point_to_symmetric_key name much since
-// point is not the only input of the function. Unify naming with TS once we have a better name.
-pub fn point_to_symmetric_key(secret: Scalar, point: Point) -> [u8; 32] {
+pub fn derive_aes_secret(secret: Scalar, point: Point) -> [u8; 32] {
     let shared_secret = point_to_bytes(multi_scalar_mul([point], [secret]));
 
     let mut shared_secret_bytes_with_separator: [u8; 33] = std::mem::zeroed();
@@ -18,7 +16,7 @@ pub fn point_to_symmetric_key(secret: Scalar, point: Point) -> [u8; 32] {
 }
 
 #[test]
-unconstrained fn test_point_to_symmetric_key_matches_noir() {
+unconstrained fn test_derive_aes_secret_matches_noir() {
     // Value taken from "derive shared secret" test in encrypt_buffer.test.ts
     let secret = Scalar {
         lo: 0x00000000000000000000000000000000649e7ca01d9de27b21624098b897babd,
@@ -30,7 +28,7 @@ unconstrained fn test_point_to_symmetric_key_matches_noir() {
         is_infinite: false,
     };
 
-    let key = point_to_symmetric_key(secret, point);
+    let key = derive_aes_secret(secret, point);
 
     // The following value was generated by `encrypt_buffer.test.ts`.
     // --> Run the test with AZTEC_GENERATE_TEST_DATA=1 flag to update test data.

yarn-project/circuit-types/src/logs/l1_payload/encryption_util.ts

@@ -1,7 +1,7 @@
 import { type GrumpkinScalar, type PublicKey } from '@aztec/circuits.js';
 import { Aes128 } from '@aztec/circuits.js/barretenberg';
 
-import { deriveDiffieHellmanAESSecret } from './shared_secret_derivation.js';
+import { deriveAESSecret } from './shared_secret_derivation.js';
 
 /**
  * Encrypts the plaintext using the secret key and public key
@@ -16,7 +16,7 @@ export function encrypt(
   plaintext: Buffer,
   secret: GrumpkinScalar,
   publicKey: PublicKey,
-  deriveSecret: (secret: GrumpkinScalar, publicKey: PublicKey) => Buffer = deriveDiffieHellmanAESSecret,
+  deriveSecret: (secret: GrumpkinScalar, publicKey: PublicKey) => Buffer = deriveAESSecret,
 ): Buffer {
   const aesSecret = deriveSecret(secret, publicKey);
   const key = aesSecret.subarray(0, 16);
@@ -38,7 +38,7 @@ export function decrypt(
   ciphertext: Buffer,
   secret: GrumpkinScalar,
   publicKey: PublicKey,
-  deriveSecret: (secret: GrumpkinScalar, publicKey: PublicKey) => Buffer = deriveDiffieHellmanAESSecret,
+  deriveSecret: (secret: GrumpkinScalar, publicKey: PublicKey) => Buffer = deriveAESSecret,
 ): Buffer {
   const aesSecret = deriveSecret(secret, publicKey);
   const key = aesSecret.subarray(0, 16);

yarn-project/circuit-types/src/logs/l1_payload/shared_secret_derivation.ts

@@ -13,10 +13,8 @@ import { numToUInt8 } from '@aztec/foundation/serialize';
  * @param publicKey - The public key used to derive shared secret.
  * @returns A derived AES secret key.
  * @throws If the public key is zero.
- * TODO(#5726): This function is called point_to_symmetric_key in Noir. I don't like that name much since point is not
- * the only input of the function. Unify naming once we have a better name.
  */
-export function deriveDiffieHellmanAESSecret(secretKey: GrumpkinScalar, publicKey: PublicKey): Buffer {
+export function deriveAESSecret(secretKey: GrumpkinScalar, publicKey: PublicKey): Buffer {
   if (publicKey.isZero()) {
     throw new Error(
       `Attempting to derive AES secret with a zero public key. You have probably passed a zero public key in your Noir code somewhere thinking that the note won't broadcasted... but it was.`,