Reduce buffer usage (#521)

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - docs: Various improvements.
 - Ran `npm audit fix`.
 - `Waku.dial` accepts protocols expected from the peer. Defaults to Waku Relay only.
+- Deprecated `hexToBuf` & `bufToHex` in favour of `hexToBytes` & `bytesToHex` to move towards removing the `buffer` polyfill.
 
 ### Removed
 

examples/eth-pm-wallet-encryption/src/crypto.ts

@@ -1,7 +1,7 @@
 import "@ethersproject/shims";
 
 import { PublicKeyMessage } from "./messaging/wire";
-import { hexToBuf, equalByteArrays, bufToHex } from "js-waku/lib/utils";
+import { hexToBytes, equalByteArrays, bytesToHex } from "js-waku/lib/utils";
 import * as sigUtil from "eth-sig-util";
 
 /**
@@ -28,8 +28,8 @@ export async function createPublicKeyMessage(
 
   return new PublicKeyMessage({
     encryptionPublicKey: encryptionPublicKey,
-    ethAddress: hexToBuf(address),
+    ethAddress: hexToBytes(address),
-    signature: hexToBuf(signature),
+    signature: hexToBytes(signature),
   });
 }
 
@@ -41,7 +41,7 @@ function buildMsgParams(encryptionPublicKey: Uint8Array, fromAddress: string) {
       version: "1",
     },
     message: {
-      encryptionPublicKey: bufToHex(encryptionPublicKey),
+      encryptionPublicKey: bytesToHex(encryptionPublicKey),
       ownerAddress: fromAddress,
     },
     // Refers to the keys of the *types* object below.
@@ -79,7 +79,7 @@ export async function signEncryptionKey(
 
   console.log("TYPED SIGNED:" + JSON.stringify(result));
 
-  return hexToBuf(result);
+  return hexToBytes(result);
 }
 
 /**
@@ -88,13 +88,13 @@ export async function signEncryptionKey(
 export function validatePublicKeyMessage(msg: PublicKeyMessage): boolean {
   const recovered = sigUtil.recoverTypedSignature_v4({
     data: JSON.parse(
-      buildMsgParams(msg.encryptionPublicKey, "0x" + bufToHex(msg.ethAddress))
+      buildMsgParams(msg.encryptionPublicKey, "0x" + bytesToHex(msg.ethAddress))
     ),
-    sig: "0x" + bufToHex(msg.signature),
+    sig: "0x" + bytesToHex(msg.signature),
   });
 
   console.log("Recovered", recovered);
-  console.log("ethAddress", "0x" + bufToHex(msg.ethAddress));
+  console.log("ethAddress", "0x" + bytesToHex(msg.ethAddress));
 
   return equalByteArrays(recovered, msg.ethAddress);
 }

examples/eth-pm-wallet-encryption/src/messaging/SendMessage.tsx

@@ -8,7 +8,7 @@ import {
 } from "@material-ui/core";
 import React, { ChangeEvent, useState, KeyboardEvent } from "react";
 import { Waku, WakuMessage } from "js-waku";
-import { bufToHex, hexToBuf } from "js-waku/lib/utils";
+import { bytesToHex, hexToBytes } from "js-waku/lib/utils";
 import { PrivateMessage } from "./wire";
 import { PrivateMessageContentTopic } from "../waku";
 import * as sigUtil from "eth-sig-util";
@@ -111,7 +111,7 @@ async function encodeEncryptedWakuMessage(
   address: string
 ): Promise<WakuMessage> {
   const privateMessage = new PrivateMessage({
-    toAddress: hexToBuf(address),
+    toAddress: hexToBytes(address),
     message: message,
   });
 
@@ -119,7 +119,7 @@ async function encodeEncryptedWakuMessage(
 
   const encObj = sigUtil.encrypt(
     Buffer.from(publicKey).toString("base64"),
-    { data: bufToHex(payload) },
+    { data: bytesToHex(payload) },
     "x25519-xsalsa20-poly1305"
   );
 

examples/eth-pm-wallet-encryption/src/waku.ts

@@ -3,7 +3,7 @@ import { Waku, WakuMessage } from "js-waku";
 import { PrivateMessage, PublicKeyMessage } from "./messaging/wire";
 import { validatePublicKeyMessage } from "./crypto";
 import { Message } from "./messaging/Messages";
-import { bufToHex, equalByteArrays } from "js-waku/lib/utils";
+import { bytesToHex, equalByteArrays } from "js-waku/lib/utils";
 
 export const PublicKeyContentTopic =
   "/eth-pm-wallet/1/encryption-public-key/proto";
@@ -44,7 +44,7 @@ export function handlePublicKeyMessage(
   if (res) {
     setPublicKeys((prevPks: Map<string, Uint8Array>) => {
       prevPks.set(
-        bufToHex(publicKeyMsg.ethAddress),
+        bytesToHex(publicKeyMsg.ethAddress),
         publicKeyMsg.encryptionPublicKey
       );
       return new Map(prevPks);

examples/eth-pm/src/crypto.ts

@@ -1,13 +1,13 @@
 import "@ethersproject/shims";
 
 import { PublicKeyMessage } from "./messaging/wire";
-import { hexToBuf, equalByteArrays, bufToHex } from "js-waku/lib/utils";
+import { hexToBytes, equalByteArrays, bytesToHex } from "js-waku/lib/utils";
 import { generatePrivateKey, getPublicKey } from "js-waku";
 import * as sigUtil from "eth-sig-util";
 import { PublicKeyContentTopic } from "./waku";
 import { keccak256 } from "ethers/lib/utils";
 
-export const PublicKeyMessageEncryptionKey = hexToBuf(
+export const PublicKeyMessageEncryptionKey = hexToBytes(
   keccak256(Buffer.from(PublicKeyContentTopic, "utf-8"))
 );
 
@@ -49,8 +49,8 @@ export async function createPublicKeyMessage(
 
   return new PublicKeyMessage({
     encryptionPublicKey: encryptionPublicKey,
-    ethAddress: hexToBuf(address),
+    ethAddress: hexToBytes(address),
-    signature: hexToBuf(signature),
+    signature: hexToBytes(signature),
   });
 }
 
@@ -62,7 +62,7 @@ function buildMsgParams(encryptionPublicKey: Uint8Array, fromAddress: string) {
       version: "1",
     },
     message: {
-      encryptionPublicKey: bufToHex(encryptionPublicKey),
+      encryptionPublicKey: bytesToHex(encryptionPublicKey),
       ownerAddress: fromAddress,
     },
     // Refers to the keys of the *types* object below.
@@ -100,7 +100,7 @@ export async function signEncryptionKey(
 
   console.log("TYPED SIGNED:" + JSON.stringify(result));
 
-  return hexToBuf(result);
+  return hexToBytes(result);
 }
 
 /**
@@ -109,13 +109,13 @@ export async function signEncryptionKey(
 export function validatePublicKeyMessage(msg: PublicKeyMessage): boolean {
   const recovered = sigUtil.recoverTypedSignature_v4({
     data: JSON.parse(
-      buildMsgParams(msg.encryptionPublicKey, "0x" + bufToHex(msg.ethAddress))
+      buildMsgParams(msg.encryptionPublicKey, "0x" + bytesToHex(msg.ethAddress))
     ),
-    sig: "0x" + bufToHex(msg.signature),
+    sig: "0x" + bytesToHex(msg.signature),
   });
 
   console.log("Recovered", recovered);
-  console.log("ethAddress", "0x" + bufToHex(msg.ethAddress));
+  console.log("ethAddress", "0x" + bytesToHex(msg.ethAddress));
 
   return equalByteArrays(recovered, msg.ethAddress);
 }

examples/eth-pm/src/key_pair_handling/key_pair_storage.ts

@@ -1,5 +1,5 @@
 import { KeyPair } from "../crypto";
-import { bufToHex, hexToBuf } from "js-waku/lib/utils";
+import { bytesToHex, hexToBytes } from "js-waku/lib/utils";
 
 /**
  * Save keypair to storage, encrypted with password
@@ -11,9 +11,9 @@ export async function saveKeyPairToStorage(
   const { salt, iv, cipher } = await encryptKey(EncryptionKeyPair, password);
 
   const data = {
-    salt: bufToHex(salt),
+    salt: bytesToHex(salt),
-    iv: bufToHex(iv),
+    iv: bytesToHex(iv),
-    cipher: bufToHex(cipher),
+    cipher: bytesToHex(cipher),
   };
 
   localStorage.setItem("cipherEncryptionKeyPair", JSON.stringify(data));
@@ -29,9 +29,9 @@ export async function loadKeyPairFromStorage(
   if (!str) return;
   const data = JSON.parse(str);
 
-  const salt = hexToBuf(data.salt);
+  const salt = hexToBytes(data.salt);
-  const iv = hexToBuf(data.iv);
+  const iv = hexToBytes(data.iv);
-  const cipher = hexToBuf(data.cipher);
+  const cipher = hexToBytes(data.cipher);
 
   return await decryptKey(salt, iv, cipher, password);
 }
@@ -96,9 +96,9 @@ async function encryptKey(encryptionKeyPair: KeyPair, password: string) {
  * Derive a key from a password, and use the key to decrypt the cipher key pair.
  */
 async function decryptKey(
-  salt: Buffer,
+  salt: Uint8Array,
-  iv: Buffer,
+  iv: Uint8Array,
-  cipherKeyPair: Buffer,
+  cipherKeyPair: Uint8Array,
   password: string
 ): Promise<KeyPair | undefined> {
   const keyMaterial = await getKeyMaterial(password);

examples/eth-pm/src/messaging/SendMessage.tsx

@@ -8,7 +8,7 @@ import {
 } from "@material-ui/core";
 import React, { ChangeEvent, useState, KeyboardEvent } from "react";
 import { Waku, WakuMessage } from "js-waku";
-import { hexToBuf } from "js-waku/lib/utils";
+import { hexToBytes } from "js-waku/lib/utils";
 import { PrivateMessage } from "./wire";
 import { PrivateMessageContentTopic } from "../waku";
 
@@ -110,7 +110,7 @@ async function encodeEncryptedWakuMessage(
   address: string
 ): Promise<WakuMessage> {
   const privateMessage = new PrivateMessage({
-    toAddress: hexToBuf(address),
+    toAddress: hexToBytes(address),
     message: message,
   });
 

examples/eth-pm/src/waku.ts

@@ -3,7 +3,7 @@ import { Waku, WakuMessage } from "js-waku";
 import { PrivateMessage, PublicKeyMessage } from "./messaging/wire";
 import { validatePublicKeyMessage } from "./crypto";
 import { Message } from "./messaging/Messages";
-import { bufToHex, equalByteArrays } from "js-waku/lib/utils";
+import { bytesToHex, equalByteArrays } from "js-waku/lib/utils";
 
 export const PublicKeyContentTopic = "/eth-pm/1/public-key/proto";
 export const PrivateMessageContentTopic = "/eth-pm/1/private-message/proto";
@@ -42,7 +42,7 @@ export function handlePublicKeyMessage(
   if (res) {
     setter((prevPks: Map<string, Uint8Array>) => {
       prevPks.set(
-        bufToHex(publicKeyMsg.ethAddress),
+        bytesToHex(publicKeyMsg.ethAddress),
         publicKeyMsg.encryptionPublicKey
       );
       return new Map(prevPks);

src/lib/enr/create.ts

@@ -1,4 +1,4 @@
-import { bufToHex } from "../utils";
+import { bytesToHex } from "../utils";
 
 import { NodeId } from "./types";
 
@@ -6,5 +6,5 @@ export function createNodeId(buffer: Buffer): NodeId {
   if (buffer.length !== 32) {
     throw new Error("NodeId must be 32 bytes in length");
   }
-  return bufToHex(buffer);
+  return bytesToHex(buffer);
 }

src/lib/enr/enr.spec.ts

@@ -2,7 +2,7 @@ import { assert, expect } from "chai";
 import { Multiaddr } from "multiaddr";
 import PeerId from "peer-id";
 
-import { bufToHex } from "../utils";
+import { bytesToHex } from "../utils";
 
 import { ERR_INVALID_ID } from "./constants";
 import { ENR } from "./enr";
@@ -31,8 +31,8 @@ describe("ENR", function () {
       const txt = enr.encodeTxt(keypair.privateKey);
       expect(txt.slice(0, 4)).to.be.equal("enr:");
       const enr2 = ENR.decodeTxt(txt);
-      expect(bufToHex(enr2.signature as Buffer)).to.be.equal(
+      expect(bytesToHex(enr2.signature as Buffer)).to.be.equal(
-        bufToHex(enr.signature as Buffer)
+        bytesToHex(enr.signature as Buffer)
       );
       const multiaddr = enr2.getLocationMultiaddr("udp")!;
       expect(multiaddr.toString()).to.be.equal("/ip4/18.223.219.100/udp/9000");
@@ -56,7 +56,7 @@ describe("ENR", function () {
       const enr = ENR.decodeTxt(txt);
       const eth2 = enr.get("eth2") as Buffer;
       expect(eth2).to.not.be.undefined;
-      expect(bufToHex(eth2)).to.be.equal("f6775d0700000113ffffffffffff1f00");
+      expect(bytesToHex(eth2)).to.be.equal("f6775d0700000113ffffffffffff1f00");
     });
 
     it("should decode valid ENR with multiaddrs successfully [shared test vector]", () => {

src/lib/utils.ts

@@ -2,6 +2,8 @@ import { keccak256, Message } from "js-sha3";
 
 /**
  * Convert input to a Buffer.
+ *
+ * @deprecated Use `hexToBytes` instead.
  */
 export function hexToBuf(hex: string | Buffer | Uint8Array): Buffer {
   if (typeof hex === "string") {
@@ -11,36 +13,66 @@ export function hexToBuf(hex: string | Buffer | Uint8Array): Buffer {
   }
 }
 
+/**
+ * Convert input to a byte array.
+ */
+export function hexToBytes(hex: string | Uint8Array): Uint8Array {
+  if (typeof hex === "string") {
+    const _hex = hex.replace(/^0x/i, "");
+    const bytes = [];
+    for (let c = 0; c < _hex.length; c += 2)
+      bytes.push(parseInt(_hex.substring(c, c + 2), 16));
+
+    return new Uint8Array(bytes);
+  }
+  return hex;
+}
+
 /**
  * Convert input to hex string (no `0x` prefix).
+ *
+ * @deprecated Use `bytesToHex` instead.
  */
 export function bufToHex(buf: Uint8Array | Buffer | ArrayBuffer): string {
   const _buf = Buffer.from(buf);
   return _buf.toString("hex");
 }
 
+/**
+ * Convert byte array to hex string (no `0x` prefix).
+ */
+export function bytesToHex(bytes: Uint8Array): string {
+  const hex = [];
+  for (let i = 0; i < bytes.length; i++) {
+    const current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
+    hex.push((current >>> 4).toString(16));
+    hex.push((current & 0xf).toString(16));
+  }
+  return hex.join("");
+}
+
 /**
  * Compare both inputs, return true if they represent the same byte array.
  */
 export function equalByteArrays(
-  a: Uint8Array | Buffer | string,
+  a: Uint8Array | string,
-  b: Uint8Array | Buffer | string
+  b: Uint8Array | string
 ): boolean {
-  let aBuf: Buffer;
+  let _a: string;
-  let bBuf: Buffer;
+  let _b: string;
   if (typeof a === "string") {
-    aBuf = hexToBuf(a);
+    _a = a.replace(/^0x/i, "").toLowerCase();
   } else {
-    aBuf = Buffer.from(a);
+    _a = bytesToHex(a);
   }
 
   if (typeof b === "string") {
-    bBuf = hexToBuf(b);
+    _b = b.replace(/^0x/i, "").toLowerCase();
   } else {
-    bBuf = Buffer.from(b);
+    _b = bytesToHex(b);
   }
 
-  return aBuf.compare(bBuf) === 0;
+  return _a === _b;
 }
 
 /**

src/lib/waku_message/index.node.spec.ts

@@ -2,13 +2,14 @@ import { expect } from "chai";
 import debug from "debug";
 
 import {
+  bytesToUtf8,
   makeLogFileName,
   NimWaku,
   NOISE_KEY_1,
   WakuRelayMessage,
 } from "../../test_utils";
 import { delay } from "../../test_utils/delay";
-import { hexToBuf } from "../utils";
+import { hexToBytes } from "../utils";
 import { Protocols, Waku } from "../waku";
 
 import {
@@ -90,8 +91,8 @@ describe("Waku Message [node only]", function () {
 
       dbg("Ask nim-waku to generate asymmetric key pair");
       const keyPair = await nimWaku.getAsymmetricKeyPair();
-      const privateKey = hexToBuf(keyPair.privateKey);
+      const privateKey = hexToBytes(keyPair.privateKey);
-      const publicKey = hexToBuf(keyPair.publicKey);
+      const publicKey = hexToBytes(keyPair.publicKey);
 
       const messageText = "This is a message I am going to encrypt";
       dbg("Encrypt message");
@@ -116,7 +117,7 @@ describe("Waku Message [node only]", function () {
 
       dbg("Check message content");
       expect(msgs[0].contentTopic).to.equal(message.contentTopic);
-      expect(hexToBuf(msgs[0].payload).toString("utf-8")).to.equal(messageText);
+      expect(bytesToUtf8(hexToBytes(msgs[0].payload))).to.equal(messageText);
     });
 
     it("JS decrypts nim message [symmetric, no signature]", async function () {
@@ -177,7 +178,7 @@ describe("Waku Message [node only]", function () {
       }
 
       expect(msgs[0].contentTopic).to.equal(message.contentTopic);
-      expect(hexToBuf(msgs[0].payload).toString("utf-8")).to.equal(messageText);
+      expect(bytesToUtf8(hexToBytes(msgs[0].payload))).to.equal(messageText);
     });
   });
 });

src/lib/waku_message/version_1.ts

@@ -5,7 +5,7 @@ import * as ecies from "ecies-geth";
 import { keccak256 } from "js-sha3";
 import * as secp256k1 from "secp256k1";
 
-import { hexToBuf } from "../utils";
+import { hexToBytes } from "../utils";
 
 import { IvSize, symmetric, SymmetricKeySize } from "./symmetric";
 
@@ -58,7 +58,7 @@ export function clearEncode(
   if (sigPrivKey) {
     envelope[0] |= IsSignedMask;
     const hash = keccak256(envelope);
-    const s = secp256k1.ecdsaSign(hexToBuf(hash), sigPrivKey);
+    const s = secp256k1.ecdsaSign(hexToBytes(hash), sigPrivKey);
     envelope = Buffer.concat([envelope, s.signature, Buffer.from([s.recid])]);
     sig = {
       signature: Buffer.from(s.signature),
@@ -116,7 +116,7 @@ export async function encryptAsymmetric(
   data: Uint8Array | Buffer,
   publicKey: Uint8Array | Buffer | string
 ): Promise<Uint8Array> {
-  return ecies.encrypt(hexToBuf(publicKey), Buffer.from(data));
+  return ecies.encrypt(Buffer.from(hexToBytes(publicKey)), Buffer.from(data));
 }
 
 /**
@@ -148,7 +148,11 @@ export async function encryptSymmetric(
   const iv = symmetric.generateIv();
 
   // Returns `cipher | tag`
-  const cipher = await symmetric.encrypt(iv, hexToBuf(key), Buffer.from(data));
+  const cipher = await symmetric.encrypt(
+    iv,
+    Buffer.from(hexToBytes(key)),
+    Buffer.from(data)
+  );
   return Buffer.concat([cipher, Buffer.from(iv)]);
 }
 
@@ -170,7 +174,7 @@ export async function decryptSymmetric(
   const cipher = data.slice(0, ivStart);
   const iv = data.slice(ivStart);
 
-  return symmetric.decrypt(iv, hexToBuf(key), cipher);
+  return symmetric.decrypt(iv, Buffer.from(hexToBytes(key)), cipher);
 }
 
 /**
@@ -250,7 +254,7 @@ function ecRecoverPubKey(messageHash: string, signature: Buffer): Uint8Array {
   return secp256k1.ecdsaRecover(
     signature.slice(0, 64),
     recovery,
-    hexToBuf(messageHash),
+    hexToBytes(messageHash),
     false
   );
 }

src/lib/waku_relay/index.ts

@@ -13,7 +13,7 @@ import { InMessage } from "libp2p-interfaces/src/pubsub";
 import { SignaturePolicy } from "libp2p-interfaces/src/pubsub/signature-policy";
 import PeerId from "peer-id";
 
-import { hexToBuf } from "../utils";
+import { hexToBytes } from "../utils";
 import { CreateOptions, DefaultPubSubTopic } from "../waku";
 import { DecryptionMethod, WakuMessage } from "../waku_message";
 
@@ -135,7 +135,7 @@ export class WakuRelay extends Gossipsub {
     key: Uint8Array | string,
     options?: { method?: DecryptionMethod; contentTopics?: string[] }
   ): void {
-    this.decryptionKeys.set(hexToBuf(key), options ?? {});
+    this.decryptionKeys.set(hexToBytes(key), options ?? {});
   }
 
   /**
@@ -145,7 +145,7 @@ export class WakuRelay extends Gossipsub {
    * Strings must be in hex format.
    */
   deleteDecryptionKey(key: Uint8Array | string): void {
-    this.decryptionKeys.delete(hexToBuf(key));
+    this.decryptionKeys.delete(hexToBytes(key));
   }
 
   /**

src/lib/waku_store/index.ts

@@ -8,7 +8,7 @@ import PeerId from "peer-id";
 
 import { HistoryResponse_Error } from "../../proto";
 import { getPeersForProtocol, selectRandomPeer } from "../select_peer";
-import { hexToBuf } from "../utils";
+import { hexToBytes } from "../utils";
 import { DefaultPubSubTopic } from "../waku";
 import { DecryptionMethod, WakuMessage } from "../waku_message";
 
@@ -181,7 +181,7 @@ export class WakuStore {
     if (opts.decryptionKeys) {
       opts.decryptionKeys.forEach((key) => {
         decryptionKeys.push({
-          key: hexToBuf(key),
+          key: hexToBytes(key),
           contentTopics: contentTopics.length ? contentTopics : undefined,
           method: undefined,
         });
@@ -276,7 +276,7 @@ export class WakuStore {
     key: Uint8Array | string,
     options?: { method?: DecryptionMethod; contentTopics?: string[] }
   ): void {
-    this.decryptionKeys.set(hexToBuf(key), options ?? {});
+    this.decryptionKeys.set(hexToBytes(key), options ?? {});
   }
 
   /**
@@ -286,7 +286,7 @@ export class WakuStore {
    * Strings must be in hex format.
    */
   deleteDecryptionKey(key: Uint8Array | string): void {
-    this.decryptionKeys.delete(hexToBuf(key));
+    this.decryptionKeys.delete(hexToBytes(key));
   }
 
   /**

src/test_utils/index.ts

@@ -9,3 +9,4 @@ export * from "./async_fs";
 export * from "./constants";
 export * from "./log_file";
 export * from "./nim_waku";
+export * from "./utf8";

src/test_utils/nim_waku.node.spec.ts

@@ -1,6 +1,6 @@
 import { expect } from "chai";
 
-import { argsToArray, bufToHex, defaultArgs, strToHex } from "./nim_waku";
+import { argsToArray, bytesToHex, defaultArgs, strToHex } from "./nim_waku";
 
 describe("nim_waku", () => {
   it("Correctly serialized arguments", function () {
@@ -37,7 +37,7 @@ describe("nim_waku", () => {
     ]);
     const expected = "5468697320697320616e207574662d3820737472696e672e";
 
-    const actual = bufToHex(buf);
+    const actual = bytesToHex(buf);
     expect(actual).to.deep.equal(expected);
   });
 });

src/test_utils/nim_waku.ts

@@ -11,7 +11,7 @@ import { Multiaddr, multiaddr } from "multiaddr";
 import PeerId from "peer-id";
 import portfinder from "portfinder";
 
-import { hexToBuf } from "../lib/utils";
+import { hexToBytes } from "../lib/utils";
 import { DefaultPubSubTopic } from "../lib/waku";
 import { WakuMessage } from "../lib/waku_message";
 import * as proto from "../proto/waku/v2/message";
@@ -203,7 +203,7 @@ export class NimWaku {
     }
 
     const rpcMessage = {
-      payload: bufToHex(message.payload),
+      payload: bytesToHex(message.payload),
       contentTopic: message.contentTopic,
       timestamp,
     };
@@ -258,7 +258,7 @@ export class NimWaku {
     return this.rpcCall<boolean>("post_waku_v2_private_v1_asymmetric_message", [
       pubSubTopic ? pubSubTopic : DefaultPubSubTopic,
       message,
-      "0x" + bufToHex(publicKey),
+      "0x" + bytesToHex(publicKey),
     ]);
   }
 
@@ -272,18 +272,18 @@ export class NimWaku {
       "get_waku_v2_private_v1_asymmetric_messages",
       [
         pubSubTopic ? pubSubTopic : DefaultPubSubTopic,
-        "0x" + bufToHex(privateKey),
+        "0x" + bytesToHex(privateKey),
       ]
     );
   }
 
-  async getSymmetricKey(): Promise<Buffer> {
+  async getSymmetricKey(): Promise<Uint8Array> {
     this.checkProcess();
 
     return this.rpcCall<string>(
       "get_waku_v2_private_v1_symmetric_key",
       []
-    ).then(hexToBuf);
+    ).then(hexToBytes);
   }
 
   async postSymmetricMessage(
@@ -300,7 +300,7 @@ export class NimWaku {
     return this.rpcCall<boolean>("post_waku_v2_private_v1_symmetric_message", [
       pubSubTopic ? pubSubTopic : DefaultPubSubTopic,
       message,
-      "0x" + bufToHex(symKey),
+      "0x" + bytesToHex(symKey),
     ]);
   }
 
@@ -312,7 +312,10 @@ export class NimWaku {
 
     return await this.rpcCall<WakuRelayMessage[]>(
       "get_waku_v2_private_v1_symmetric_messages",
-      [pubSubTopic ? pubSubTopic : DefaultPubSubTopic, "0x" + bufToHex(symKey)]
+      [
+        pubSubTopic ? pubSubTopic : DefaultPubSubTopic,
+        "0x" + bytesToHex(symKey),
+      ]
     );
   }
 
@@ -416,7 +419,7 @@ export function strToHex(str: string): string {
   return hex;
 }
 
-export function bufToHex(buffer: Uint8Array): string {
+export function bytesToHex(buffer: Uint8Array): string {
   return Array.prototype.map
     .call(buffer, (x) => ("00" + x.toString(16)).slice(-2))
     .join("");

src/test_utils/utf8.ts

@@ -0,0 +1,43 @@
+// Thanks https://gist.github.com/pascaldekloe/62546103a1576803dade9269ccf76330
+export function bytesToUtf8(bytes: Uint8Array): string {
+  let i = 0,
+    s = "";
+  while (i < bytes.length) {
+    let c = bytes[i++];
+    if (c > 127) {
+      if (c > 191 && c < 224) {
+        if (i >= bytes.length)
+          throw new Error("UTF-8 decode: incomplete 2-byte sequence");
+        c = ((c & 31) << 6) | (bytes[i++] & 63);
+      } else if (c > 223 && c < 240) {
+        if (i + 1 >= bytes.length)
+          throw new Error("UTF-8 decode: incomplete 3-byte sequence");
+        c = ((c & 15) << 12) | ((bytes[i++] & 63) << 6) | (bytes[i++] & 63);
+      } else if (c > 239 && c < 248) {
+        if (i + 2 >= bytes.length)
+          throw new Error("UTF-8 decode: incomplete 4-byte sequence");
+        c =
+          ((c & 7) << 18) |
+          ((bytes[i++] & 63) << 12) |
+          ((bytes[i++] & 63) << 6) |
+          (bytes[i++] & 63);
+      } else
+        throw new Error(
+          "UTF-8 decode: unknown multi byte start 0x" +
+            c.toString(16) +
+            " at index " +
+            (i - 1)
+        );
+    }
+    if (c <= 0xffff) s += String.fromCharCode(c);
+    else if (c <= 0x10ffff) {
+      c -= 0x10000;
+      s += String.fromCharCode((c >> 10) | 0xd800);
+      s += String.fromCharCode((c & 0x3ff) | 0xdc00);
+    } else
+      throw new Error(
+        "UTF-8 decode: code point 0x" + c.toString(16) + " exceeds UTF-16 reach"
+      );
+  }
+  return s;
+}