Promote dedicated symmetric key generation API

Using the private key API for symmetric key is confusing.

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - **Breaking**: Moved `startTime` and `endTime` for history queries to a `timeFilter` property as both or neither must be passed; passing only one parameter is not supported.
+- Renamed and promote the usage of `generateSymmetricKey()` to generate random symmetric keys.
 
 ### Fixed
 - Buffer concat error when using symmetric encryption in the browser.

README.md

@@ -138,14 +138,14 @@ A quick note on the cryptographic libraries used as it is a not a straightforwar
 Asymmetric private keys and symmetric keys are expected to be 32 bytes arrays.
 
 ```ts
-import { generatePrivateKey, getPublicKey } from 'js-waku';
+import { generatePrivateKey, generateSymmetricKey, getPublicKey } from 'js-waku';
 
 // Asymmetric
 const privateKey = generatePrivateKey();
 const publicKey = getPublicKey(privateKey);
 
 // Symmetric
-const symKey = generatePrivateKey();
+const symKey = generateSymmetricKey();
 ```
 
 #### Encrypt Waku Messages

guides/encrypt-messages-version-1.md

@@ -62,9 +62,9 @@ To use symmetric encryption, you first need to generate a key.
 You can simply use `generatePrivateKey` for secure key generation:
 
 ```js
-import { generatePrivateKey } from 'js-waku';
+import { generateSymmetricKey } from 'js-waku';
 
-const key = generatePrivateKey();
+const key = generateSymmetricKey();
 ```
 
 ### Encrypt Message

src/index.ts

@@ -6,7 +6,11 @@ export { Waku, DefaultPubSubTopic } from './lib/waku';
 
 export { WakuMessage } from './lib/waku_message';
 
-export { generatePrivateKey, getPublicKey } from './lib/waku_message/version_1';
+export {
+  generatePrivateKey,
+  generateSymmetricKey,
+  getPublicKey,
+} from './lib/waku_message/version_1';
 
 export {
   WakuLightPush,

src/lib/waku_message/index.spec.ts

@@ -14,7 +14,11 @@ import { delay } from '../delay';
 import { hexToBuf } from '../utils';
 import { Waku } from '../waku';
 
-import { generatePrivateKey, getPublicKey } from './version_1';
+import {
+  generatePrivateKey,
+  generateSymmetricKey,
+  getPublicKey,
+} from './version_1';
 
 import { WakuMessage } from './index';
 
@@ -122,7 +126,7 @@ describe('Waku Message: Node only', function () {
         payload: Buffer.from(messageText, 'utf-8').toString('hex'),
       };
 
-      const symKey = generatePrivateKey();
+      const symKey = generateSymmetricKey();
 
       waku.relay.addDecryptionKey(symKey);
 

src/lib/waku_message/symmetric/browser.ts

@@ -1,4 +1,4 @@
-import { IvSize, SymmetricKeySize } from './index';
+import { IvSize } from './index';
 
 declare global {
   interface Window {
@@ -44,10 +44,6 @@ export async function decrypt(
     .then(Buffer.from);
 }
 
-export function generateKeyForSymmetricEnc(): Buffer {
-  return crypto.getRandomValues(Buffer.alloc(SymmetricKeySize));
-}
-
 export function generateIv(): Uint8Array {
   const iv = new Uint8Array(IvSize);
   crypto.getRandomValues(iv);

src/lib/waku_message/symmetric/index.ts

@@ -15,10 +15,6 @@ export interface Symmetric {
    * Proceed with symmetric decryption of `cipherText` value.
    */
   decrypt: (iv: Buffer, key: Buffer, cipherText: Buffer) => Promise<Buffer>;
-  /**
-   * Generate a new private key for Symmetric encryption purposes.
-   */
-  generateKeyForSymmetricEnc: () => Buffer;
   /**
    * Generate an Initialization Vector (iv) for for Symmetric encryption purposes.
    */

src/lib/waku_message/symmetric/node.ts

@@ -1,6 +1,6 @@
 import { createCipheriv, createDecipheriv, randomBytes } from 'crypto';
 
-import { IvSize, SymmetricKeySize, TagSize } from './index';
+import { IvSize, TagSize } from './index';
 
 const Algorithm = 'aes-256-gcm';
 
@@ -31,10 +31,6 @@ export async function decrypt(
   return Buffer.concat([a, b]);
 }
 
-export function generateKeyForSymmetricEnc(): Buffer {
-  return randomBytes(SymmetricKeySize);
-}
-
 export function generateIv(): Buffer {
   return randomBytes(IvSize);
 }

src/lib/waku_message/version_1.ts

@@ -7,7 +7,7 @@ import * as secp256k1 from 'secp256k1';
 
 import { hexToBuf } from '../utils';
 
-import { IvSize, symmetric } from './symmetric';
+import { IvSize, symmetric, SymmetricKeySize } from './symmetric';
 
 const FlagsLength = 1;
 const FlagMask = 3; // 0011
@@ -15,6 +15,8 @@ const IsSignedMask = 4; // 0100
 const PaddingTarget = 256;
 const SignatureLength = 65;
 
+export const PrivateKeySize = 32;
+
 /**
  * Encode the payload pre-encryption.
  *
@@ -172,14 +174,19 @@ export async function decryptSymmetric(
 }
 
 /**
- * Generate a new key. Can be used as a private key for Asymmetric encryption
- * or a key for symmetric encryption.
+ * Generate a new private key to be used for asymmetric encryption.
  *
- * If using Asymmetric encryption, use {@link getPublicKey} to get the
- * corresponding Public Key.
+ * Use {@link getPublicKey} to get the corresponding Public Key.
  */
 export function generatePrivateKey(): Uint8Array {
-  return randomBytes(32);
+  return randomBytes(PrivateKeySize);
+}
+
+/**
+ * Generate a new symmetric key to be used for symmetric encryption.
+ */
+export function generateSymmetricKey(): Uint8Array {
+  return randomBytes(SymmetricKeySize);
 }
 
 /**

src/lib/waku_store/index.spec.ts

@@ -13,7 +13,11 @@ import {
 import { delay } from '../delay';
 import { Waku } from '../waku';
 import { WakuMessage } from '../waku_message';
-import { generatePrivateKey, getPublicKey } from '../waku_message/version_1';
+import {
+  generatePrivateKey,
+  generateSymmetricKey,
+  getPublicKey,
+} from '../waku_message/version_1';
 
 import { Direction } from './history_rpc';
 
@@ -160,7 +164,7 @@ describe('Waku Store', () => {
       'This message is not for and I must not be able to read it';
 
     const privateKey = generatePrivateKey();
-    const symKey = generatePrivateKey();
+    const symKey = generateSymmetricKey();
     const publicKey = getPublicKey(privateKey);
 
     const [