fixing key naming + arg order

yarn-project/circuit-types/src/logs/l1_note_payload/encrypt_buffer.test.ts

@@ -14,14 +14,14 @@ describe('encrypt buffer', () => {
 
   it('derive shared secret', () => {
     // The following 2 are arbitrary fixed values - fixed in order to test a match with Noir
-    const ownerPrivKey: GrumpkinScalar = new Fq(0x23b3127c127b1f29a7adff5cccf8fb06649e7ca01d9de27b21624098b897babdn);
-    const ephPrivKey: GrumpkinScalar = new Fq(0x1fdd0dd8c99b21af8e00d2d130bdc263b36dadcbea84ac5ec9293a0660deca01n);
+    const ownerSecretKey: GrumpkinScalar = new Fq(0x23b3127c127b1f29a7adff5cccf8fb06649e7ca01d9de27b21624098b897babdn);
+    const ephSecretKey: GrumpkinScalar = new Fq(0x1fdd0dd8c99b21af8e00d2d130bdc263b36dadcbea84ac5ec9293a0660deca01n);
 
-    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerPrivKey);
-    const ephPubKey = grumpkin.mul(Grumpkin.generator, ephPrivKey);
+    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerSecretKey);
+    const ephPubKey = grumpkin.mul(Grumpkin.generator, ephSecretKey);
 
-    const secretBySender = deriveAESSecret(ownerPubKey, ephPrivKey);
-    const secretByReceiver = deriveAESSecret(ephPubKey, ownerPrivKey);
+    const secretBySender = deriveAESSecret(ephSecretKey, ownerPubKey);
+    const secretByReceiver = deriveAESSecret(ownerSecretKey, ephPubKey);
     expect(secretBySender.toString('hex')).toEqual(secretByReceiver.toString('hex'));
 
     const byteArrayString = `[${secretBySender
@@ -38,26 +38,26 @@ describe('encrypt buffer', () => {
 
   it('convert to and from encrypted buffer', () => {
     const data = randomBytes(253);
-    const ownerPrivKey = GrumpkinScalar.random();
-    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerPrivKey);
-    const ephPrivKey = GrumpkinScalar.random();
-    const encrypted = encryptBuffer(data, ownerPubKey, ephPrivKey);
-    const decrypted = decryptBuffer(encrypted, ownerPrivKey);
+    const ownerSecretKey = GrumpkinScalar.random();
+    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerSecretKey);
+    const ephSecretKey = GrumpkinScalar.random();
+    const encrypted = encryptBuffer(data, ephSecretKey, ownerPubKey);
+    const decrypted = decryptBuffer(encrypted, ownerSecretKey);
     expect(decrypted).not.toBeUndefined();
     expect(decrypted).toEqual(data);
   });
 
   it('decrypting gibberish returns undefined', () => {
     const data = randomBytes(253);
-    const ownerPrivKey = GrumpkinScalar.random();
-    const ephPrivKey = GrumpkinScalar.random();
-    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerPrivKey);
-    const encrypted = encryptBuffer(data, ownerPubKey, ephPrivKey);
+    const ownerSecretKey = GrumpkinScalar.random();
+    const ephSecretKey = GrumpkinScalar.random();
+    const ownerPubKey = grumpkin.mul(Grumpkin.generator, ownerSecretKey);
+    const encrypted = encryptBuffer(data, ephSecretKey, ownerPubKey);
 
     // Introduce gibberish.
     const gibberish = Buffer.concat([randomBytes(8), encrypted.subarray(8)]);
 
-    const decrypted = decryptBuffer(gibberish, ownerPrivKey);
+    const decrypted = decryptBuffer(gibberish, ownerSecretKey);
     expect(decrypted).toBeUndefined();
   });
 });

yarn-project/circuit-types/src/logs/l1_note_payload/encrypt_buffer.ts

@@ -12,15 +12,15 @@ import { createCipheriv, createDecipheriv } from 'browserify-cipher';
  * the shared secret. The shared secret is then hashed using SHA-256 to produce the final
  * AES secret key.
  *
- * @param ecdhPubKey - The ECDH public key represented as a PublicKey object.
- * @param ecdhPrivKey - The ECDH private key represented as a Buffer object.
- * @returns A Buffer containing the derived AES secret key.
+ * @param secretKey - The secret key used to derive shared secret.
+ * @param publicKey - The public key used to derive shared secret.
+ * @returns A derived AES secret key.
  * 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 deriveAESSecret(ecdhPubKey: PublicKey, ecdhPrivKey: GrumpkinPrivateKey): Buffer {
+export function deriveAESSecret(secretKey: GrumpkinPrivateKey, publicKey: PublicKey): Buffer {
   const curve = new Grumpkin();
-  const sharedSecret = curve.mul(ecdhPubKey, ecdhPrivKey);
+  const sharedSecret = curve.mul(publicKey, secretKey);
   const secretBuffer = Buffer.concat([sharedSecret.toBuffer(), numToUInt8(GeneratorIndex.SYMMETRIC_KEY)]);
   const hash = sha256(secretBuffer);
   return hash;
@@ -33,35 +33,37 @@ export function deriveAESSecret(ecdhPubKey: PublicKey, ecdhPrivKey: GrumpkinPriv
  * with the provided curve instance for elliptic curve operations.
  *
  * @param data - The data buffer to be encrypted.
- * @param ownerPubKey - The owner's public key as a PublicKey instance.
- * @param ephPrivKey - The ephemeral private key as a Buffer instance.
+ * @param ephSecretKey - The ephemeral secret key..
+ * @param incomingViewingPublicKey - The note owner's incoming viewing public key.
  * @returns A Buffer containing the encrypted data and the ephemeral public key.
  */
-export function encryptBuffer(data: Buffer, ownerPubKey: PublicKey, ephPrivKey: GrumpkinPrivateKey): Buffer {
-  const aesSecret = deriveAESSecret(ownerPubKey, ephPrivKey);
+export function encryptBuffer(
+  data: Buffer,
+  ephSecretKey: GrumpkinPrivateKey,
+  incomingViewingPublicKey: PublicKey,
+): Buffer {
+  const aesSecret = deriveAESSecret(ephSecretKey, incomingViewingPublicKey);
   const aesKey = aesSecret.subarray(0, 16);
   const iv = aesSecret.subarray(16, 32);
   const cipher = createCipheriv('aes-128-cbc', aesKey, iv);
   const plaintext = Buffer.concat([iv.subarray(0, 8), data]);
   const curve = new Grumpkin();
-  const ephPubKey = curve.mul(curve.generator(), ephPrivKey);
+  const ephPubKey = curve.mul(curve.generator(), ephSecretKey);
 
   return Buffer.concat([cipher.update(plaintext), cipher.final(), ephPubKey.toBuffer()]);
 }
 
 /**
- * Decrypts the given encrypted data buffer using the owner's private key and a Grumpkin curve.
- * Extracts the ephemeral public key from the input data, derives the AES secret using
- * the owner's private key, and decrypts the plaintext.
- * If the decryption is successful, returns the decrypted plaintext, otherwise returns undefined.
- *
+ * Decrypts the given encrypted data buffer using the provided secret key.
  * @param data - The encrypted data buffer to be decrypted.
- * @param ownerPrivKey - The private key of the owner used for decryption.
+ * @param incomingViewingSecretKey - The secret key used for decryption.
  * @returns The decrypted plaintext as a Buffer or undefined if decryption fails.
  */
-export function decryptBuffer(data: Buffer, ownerPrivKey: GrumpkinPrivateKey): Buffer | undefined {
+export function decryptBuffer(data: Buffer, incomingViewingSecretKey: GrumpkinPrivateKey): Buffer | undefined {
+  // Extract the ephemeral public key from the end of the data
   const ephPubKey = Point.fromBuffer(data.subarray(-64));
-  const aesSecret = deriveAESSecret(ephPubKey, ownerPrivKey);
+  // Derive the AES secret key using the secret key and the ephemeral public key
+  const aesSecret = deriveAESSecret(incomingViewingSecretKey, ephPubKey);
   const aesKey = aesSecret.subarray(0, 16);
   const iv = aesSecret.subarray(16, 32);
   const cipher = createDecipheriv('aes-128-cbc', aesKey, iv);

yarn-project/circuit-types/src/logs/l1_note_payload/l1_note_payload.ts

@@ -55,22 +55,22 @@ export class L1NotePayload {
 
   /**
    * Encrypt the L1NotePayload object using the owner's public key and the ephemeral private key.
-   * @param ownerPubKey - Public key of the owner of the L1NotePayload object.
+   * @param incomingViewingPubKey - Public key of the owner of the L1NotePayload object.
    * @returns The encrypted L1NotePayload object.
    */
-  public toEncryptedBuffer(ownerPubKey: PublicKey): Buffer {
-    const ephPrivKey: GrumpkinPrivateKey = GrumpkinScalar.random();
-    return encryptBuffer(this.toBuffer(), ownerPubKey, ephPrivKey);
+  public toEncryptedBuffer(incomingViewingPubKey: PublicKey): Buffer {
+    const ephSecretKey: GrumpkinPrivateKey = GrumpkinScalar.random();
+    return encryptBuffer(this.toBuffer(), ephSecretKey, incomingViewingPubKey);
   }
 
   /**
-   * Decrypts the L1NotePayload object using the owner's private key.
+   * Decrypts the L1NotePayload object using the owner's incoming viewing secret key.
    * @param data - Encrypted L1NotePayload object.
-   * @param ownerPrivKey - Private key of the owner of the L1NotePayload object.
+   * @param incomingViewingSecretKey - Incoming viewing secret key of the owner of the L1NotePayload object.
    * @returns Instance of L1NotePayload if the decryption was successful, undefined otherwise.
    */
-  static fromEncryptedBuffer(data: Buffer, ownerPrivKey: GrumpkinPrivateKey): L1NotePayload | undefined {
-    const buf = decryptBuffer(data, ownerPrivKey);
+  static fromEncryptedBuffer(data: Buffer, incomingViewingSecretKey: GrumpkinPrivateKey): L1NotePayload | undefined {
+    const buf = decryptBuffer(data, incomingViewingSecretKey);
     if (!buf) {
       return;
     }