refactor: constructors and QR

.cspell.json

@@ -6,7 +6,10 @@
     "Waku",
     "keypair",
     "nwaku",
-    "Nametag, ciphertext",
+    "wakunoise",
+    "HMACDRBG",
+    "Nametag",
+    "ciphertext",
     "unpad",
     "blocksize",
     "Nametag",

src/codec.ts

@@ -34,7 +34,8 @@ export class NoiseHandshakeEncoder implements Encoder {
 
 export class NoiseHandshakeMessage extends MessageV0 implements Message {
   get payloadV2(): PayloadV2 {
-    return PayloadV2.deserialize(this.payload!);
+    if (!this.payload) throw new Error("no payload available");
+    return PayloadV2.deserialize(this.payload);
   }
 }
 

src/handshake.ts

@@ -38,14 +38,14 @@ export class HandshakeStepResult {
 // The recipient static key rs and handshake hash values h are stored to address some possible future applications (channel-binding, session management, etc.).
 // However, are not required by Noise specifications and are thus optional
 export class HandshakeResult {
-  csOutbound?: CipherState;
-  csInbound?: CipherState;
   // Optional fields:
   nametagsInbound: MessageNametagBuffer = new MessageNametagBuffer();
   nametagsOutbound: MessageNametagBuffer = new MessageNametagBuffer();
   rs: bytes32 = new Uint8Array();
   h: bytes32 = new Uint8Array();
 
+  constructor(private csOutbound: CipherState, private csInbound: CipherState) {}
+
   // Noise specification, Section 5:
   // Transport messages are then encrypted and decrypted by calling EncryptWithAd()
   // and DecryptWithAd() on the relevant CipherState with zero-length associated data.
@@ -70,7 +70,7 @@ export class HandshakeResult {
     // We pad the transport message
     const paddedTransportMessage = pkcs7.pad(transportMessage, NoisePaddingBlockSize);
     // Encryption is done with zero-length associated data as per specification
-    payload2.transportMessage = this.csOutbound!.encryptWithAd(payload2.messageNametag, paddedTransportMessage);
+    payload2.transportMessage = this.csOutbound.encryptWithAd(payload2.messageNametag, paddedTransportMessage);
 
     return payload2;
   }
@@ -97,7 +97,7 @@ export class HandshakeResult {
       // On application level we decide to discard messages which fail decryption, without raising an error
       try {
         // Decryption is done with messageNametag as associated data
-        const paddedMessage = this.csInbound!.decryptWithAd(readPayload2.messageNametag, readPayload2.transportMessage);
+        const paddedMessage = this.csInbound.decryptWithAd(readPayload2.messageNametag, readPayload2.transportMessage);
         // We unpad the decrypted message
         message = pkcs7.unpad(paddedMessage);
         // The message successfully decrypted, we can delete the first element of the inbound Message Nametag Buffer
@@ -245,7 +245,7 @@ export class Handshake {
 
   // Finalizes the handshake by calling Split and assigning the proper Cipher States to users
   finalizeHandshake(): HandshakeResult {
-    const hsResult = new HandshakeResult();
+    let hsResult: HandshakeResult;
 
     // Noise specification, Section 5:
     // Processing the final handshake message returns two CipherState objects,
@@ -260,14 +260,12 @@ export class Handshake {
 
     // We assign the proper Cipher States
     if (this.hs.initiator) {
-      hsResult.csOutbound = cs1;
-      hsResult.csInbound = cs2;
+      hsResult = new HandshakeResult(cs1, cs2);
       // and nametags secrets
       hsResult.nametagsInbound.secret = nms1;
       hsResult.nametagsOutbound.secret = nms2;
     } else {
-      hsResult.csOutbound = cs2;
-      hsResult.csInbound = cs1;
+      hsResult = new HandshakeResult(cs2, cs1);
       // and nametags secrets
       hsResult.nametagsInbound.secret = nms2;
       hsResult.nametagsOutbound.secret = nms1;
@@ -277,8 +275,10 @@ export class Handshake {
     hsResult.nametagsInbound.initNametagsBuffer();
     hsResult.nametagsOutbound.initNametagsBuffer();
 
+    if (!this.hs.rs) throw new Error("invalid handshake state");
+
     // We store the optional fields rs and h
-    hsResult.rs = new Uint8Array(this.hs.rs!);
+    hsResult.rs = new Uint8Array(this.hs.rs);
     hsResult.h = new Uint8Array(this.hs.ss.h);
 
     return hsResult;

src/index.ts

@@ -24,7 +24,7 @@ import {
 } from "./patterns";
 import { MessageNametagBuffer } from "./payload";
 import { ChaChaPolyCipherState, NoisePublicKey } from "./publickey";
-import { fromQr, toQr } from "./utils";
+import { QR } from "./qr";
 
 export { Handshake, HandshakeParameters, HandshakeResult, HandshakeStepResult, StepHandshakeParameters };
 export { generateX25519KeyPair, generateX25519KeyPairFromSeed };
@@ -41,4 +41,4 @@ export {
 export { ChaChaPolyCipherState, NoisePublicKey };
 export { MessageNametagBuffer };
 export { NoiseHandshakeDecoder, NoiseHandshakeEncoder, NoiseSecureTransferDecoder, NoiseSecureTransferEncoder };
-export { fromQr, toQr };
+export { QR };

src/noise.ts

@@ -156,11 +156,10 @@ function hashProtocol(name: string): Uint8Array {
 // Contains a Cipher State cs, the chaining key ck and the handshake hash value h
 export class SymmetricState {
   cs: CipherState;
-  ck: bytes32; // chaining key
   h: bytes32; // handshake hash
-  hsPattern: HandshakePattern;
+  private ck: bytes32; // chaining key
 
-  constructor(hsPattern: HandshakePattern) {
+  constructor(private readonly hsPattern: HandshakePattern) {
     this.h = hashProtocol(hsPattern.name);
     this.ck = this.h;
     this.cs = new CipherState();

src/patterns.ts

@@ -21,13 +21,7 @@ export enum MessageDirection {
 // The pre message pattern consisting of a message direction and some Noise tokens, if any.
 // (if non empty, only tokens e and s are allowed: http://www.noiseprotocol.org/noise.html#handshake-pattern-basics)
 export class PreMessagePattern {
-  direction: MessageDirection;
-  tokens: Array<NoiseTokens>;
-
-  constructor(direction: MessageDirection, tokens: Array<NoiseTokens>) {
-    this.direction = direction;
-    this.tokens = tokens;
-  }
+  constructor(public readonly direction: MessageDirection, public readonly tokens: Array<NoiseTokens>) {}
 
   equals(b: PreMessagePattern): boolean {
     return (
@@ -41,13 +35,7 @@ export class PreMessagePattern {
 // The message pattern consisting of a message direction and some Noise tokens
 // All Noise tokens are allowed
 export class MessagePattern {
-  direction: MessageDirection;
-  tokens: Array<NoiseTokens>;
-
-  constructor(direction: MessageDirection, tokens: Array<NoiseTokens>) {
-    this.direction = direction;
-    this.tokens = tokens;
-  }
+  constructor(public readonly direction: MessageDirection, public readonly tokens: Array<NoiseTokens>) {}
 
   equals(b: MessagePattern): boolean {
     return (
@@ -60,15 +48,11 @@ export class MessagePattern {
 
 // The handshake pattern object. It stores the handshake protocol name, the handshake pre message patterns and the handshake message patterns
 export class HandshakePattern {
-  name: string;
-  preMessagePatterns: Array<PreMessagePattern>;
-  messagePatterns: Array<MessagePattern>;
-
-  constructor(name: string, preMessagePatterns: Array<PreMessagePattern>, messagePatterns: Array<MessagePattern>) {
-    this.name = name;
-    this.preMessagePatterns = preMessagePatterns;
-    this.messagePatterns = messagePatterns;
-  }
+  constructor(
+    public readonly name: string,
+    public readonly preMessagePatterns: Array<PreMessagePattern>,
+    public readonly messagePatterns: Array<MessagePattern>
+  ) {}
 
   equals(b: HandshakePattern): boolean {
     if (this.preMessagePatterns.length != b.preMessagePatterns.length) return false;

src/payload.ts

@@ -19,8 +19,8 @@ export function toMessageNametag(input: Uint8Array): MessageNametag {
 }
 
 export class MessageNametagBuffer {
-  buffer: Array<MessageNametag> = new Array<MessageNametag>(MessageNametagBufferSize);
-  counter = 0;
+  private buffer: Array<MessageNametag> = new Array<MessageNametag>(MessageNametagBufferSize);
+  private counter = 0;
   secret?: Uint8Array;
 
   constructor() {
@@ -87,8 +87,8 @@ export class MessageNametagBuffer {
     if (this.secret) {
       // We rotate left the array by n
       for (let i = 0; i < n; i++) {
-        const first = this.buffer.shift()!;
-        this.buffer.push(first);
+        const first = this.buffer.shift();
+        if (first) this.buffer.push(first);
       }
 
       for (let i = 0; i < n; i++) {

src/publickey.ts

@@ -50,13 +50,7 @@ export class ChaChaPolyCipherState {
 // or the encryption of the X coordinate concatenated with the authorization tag, if encrypted (this implies flag = 1)
 // Note: besides encryption, flag can be used to distinguish among multiple supported Elliptic Curves
 export class NoisePublicKey {
-  flag: number;
-  pk: Uint8Array;
-
-  constructor(flag: number, pk: Uint8Array) {
-    this.flag = flag;
-    this.pk = pk;
-  }
+  constructor(public readonly flag: number, public readonly pk: Uint8Array) {}
 
   clone(): NoisePublicKey {
     return new NoisePublicKey(this.flag, new Uint8Array(this.pk));

src/qr.ts

@@ -0,0 +1,44 @@
+import { decode, encode, fromUint8Array, toUint8Array } from "js-base64";
+
+import { bytes32 } from "./@types/basic";
+
+export class QR {
+  constructor(
+    public readonly applicationName: string,
+    public readonly applicationVersion: string,
+    public readonly shardId: string,
+    public readonly ephemeralKey: bytes32,
+    public readonly committedStaticKey: bytes32
+  ) {}
+
+  // Serializes input parameters to a base64 string for exposure through QR code (used by WakuPairing)
+  toString(): string {
+    let qr = encode(this.applicationName) + ":";
+    qr += encode(this.applicationVersion) + ":";
+    qr += encode(this.shardId) + ":";
+    qr += fromUint8Array(this.ephemeralKey) + ":";
+    qr += fromUint8Array(this.committedStaticKey);
+
+    return qr;
+  }
+
+  toByteArray(): Uint8Array {
+    const enc = new TextEncoder();
+    return enc.encode(this.toString());
+  }
+
+  // Deserializes input string in base64 to the corresponding (applicationName, applicationVersion, shardId, ephemeralKey, committedStaticKey)
+  static fromString(qrString: string): QR {
+    const values = qrString.split(":");
+
+    if (values.length != 5) throw new Error("invalid qr string");
+
+    const applicationName = decode(values[0]);
+    const applicationVersion = decode(values[1]);
+    const shardId = decode(values[2]);
+    const ephemeralKey = toUint8Array(values[3]);
+    const committedStaticKey = toUint8Array(values[4]);
+
+    return new QR(applicationName, applicationVersion, shardId, ephemeralKey, committedStaticKey);
+  }
+}

src/utils.ts

@@ -1,9 +1,5 @@
 // Adapted from https://github.com/feross/buffer
 
-import { decode, encode, fromUint8Array, toUint8Array } from "js-base64";
-
-import { bytes32 } from "./@types/basic";
-
 function checkInt(buf: Uint8Array, value: number, offset: number, ext: number, max: number, min: number): void {
   if (value > max || value < min) throw new RangeError('"value" argument is out of bounds');
   if (offset + ext > buf.length) throw new RangeError("Index out of range");
@@ -53,41 +49,3 @@ export function readUIntLE(buf: Uint8Array, offset: number, byteLength: number,
 
   return val;
 }
-
-// Serializes input parameters to a base64 string for exposure through QR code (used by WakuPairing)
-export function toQr(
-  applicationName: string,
-  applicationVersion: string,
-  shardId: string,
-  ephemeralKey: bytes32,
-  committedStaticKey: bytes32
-): string {
-  let qr = encode(applicationName) + ":";
-  qr += encode(applicationVersion) + ":";
-  qr += encode(shardId) + ":";
-  qr += fromUint8Array(ephemeralKey) + ":";
-  qr += fromUint8Array(committedStaticKey);
-
-  return qr;
-}
-
-// Deserializes input string in base64 to the corresponding (applicationName, applicationVersion, shardId, ephemeralKey, committedStaticKey)
-export function fromQr(qr: string): {
-  applicationName: string;
-  applicationVersion: string;
-  shardId: string;
-  ephemeralKey: bytes32;
-  committedStaticKey: bytes32;
-} {
-  const values = qr.split(":");
-
-  if (values.length != 5) throw new Error("invalid qr string");
-
-  const applicationName = decode(values[0]);
-  const applicationVersion = decode(values[1]);
-  const shardId = decode(values[2]);
-  const ephemeralKey = toUint8Array(values[3]);
-  const committedStaticKey = toUint8Array(values[4]);
-
-  return { applicationName, applicationVersion, shardId, ephemeralKey, committedStaticKey };
-}

src/waku-noise-pairing.spec.ts

@@ -14,7 +14,7 @@ import { Handshake } from "./handshake";
 import { NoiseHandshakePatterns } from "./patterns";
 import { MessageNametagBufferSize, MessageNametagLength } from "./payload";
 import { NoisePublicKey } from "./publickey";
-import { fromQr, toQr } from "./utils";
+import { QR } from "./qr";
 
 describe("Waku Noise Sessions", () => {
   const rng = new HMACDRBG();
@@ -48,12 +48,10 @@ describe("Waku Noise Sessions", () => {
     // Out-of-band Communication
 
     // Bob prepares the QR and sends it out-of-band to Alice
-    const qr = toQr(applicationName, applicationVersion, shardId, bobEphemeralKey.publicKey, bobCommittedStaticKey);
-    const enc = new TextEncoder();
-    const qrBytes = enc.encode(qr);
+    const qr = new QR(applicationName, applicationVersion, shardId, bobEphemeralKey.publicKey, bobCommittedStaticKey);
 
     // Alice deserializes the QR code
-    const readQR = fromQr(qr);
+    const readQR = QR.fromString(qr.toString());
 
     // We check if QR serialization/deserialization works
     expect(readQR.applicationName).to.be.equals(applicationName);
@@ -76,7 +74,7 @@ describe("Waku Noise Sessions", () => {
       hsPattern,
       ephemeralKey: aliceEphemeralKey,
       staticKey: aliceStaticKey,
-      prologue: qrBytes,
+      prologue: qr.toByteArray(),
       preMessagePKs,
       initiator: true,
     });
@@ -84,7 +82,7 @@ describe("Waku Noise Sessions", () => {
       hsPattern,
       ephemeralKey: bobEphemeralKey,
       staticKey: bobStaticKey,
-      prologue: qrBytes,
+      prologue: qr.toByteArray(),
       preMessagePKs,
     });