Update encoder functions

src/encoder.ts

@@ -14,14 +14,34 @@ export const uint16BEDecode = data => {
 };
 uint16BEDecode.bytes = 2;
 
-export function encodeMessageBuffer(message: MessageBuffer): bytes {
+export function encode0(message: MessageBuffer): bytes {
+  return Buffer.concat([message.ne, message.ciphertext]);
+}
+
+export function encode1(message: MessageBuffer): bytes {
   return Buffer.concat([message.ne, message.ns, message.ciphertext]);
 }
 
-export function decodeMessageBuffer(message: bytes): MessageBuffer {
+export function decode0(input: bytes): MessageBuffer {
+  if (input.length < 32) {
+    throw new Error("Cannot decode stage 0 MessageBuffer: length less than 32 bytes.");
+  }
+
   return {
-    ne: message.slice(0, 32),
-    ns: message.slice(32, 64),
-    ciphertext: message.slice(64, message.length),
+    ne: input.slice(0, 32),
+    ciphertext: input.slice(32, input.length),
+    ns: Buffer.alloc(0),
+  }
+}
+
+export function decode1(input: bytes): MessageBuffer {
+  if (input.length < 96) {
+    throw new Error("Cannot decode stage 0 MessageBuffer: length less than 96 bytes.");
+  }
+
+  return {
+    ne: input.slice(0, 32),
+    ns: input.slice(32, 64),
+    ciphertext: input.slice(64, input.length),
   }
 }

src/handshake-xx-fallback.ts

@@ -12,8 +12,8 @@ import {
   verifySignedPayload,
 } from "./utils";
 import { logger } from "./logger";
-import { decodeMessageBuffer, encodeMessageBuffer } from "./encoder";
 import { WrappedConnection } from "./noise";
+import {decode0, decode1, encode1} from "./encoder";
 
 export class Handshake extends XXHandshake {
   private ephemeralKeys: KeyPair;
@@ -43,7 +43,7 @@ export class Handshake extends XXHandshake {
       logger("XX Fallback Stage 0 - Initialized state as the first message was sent by initiator.");
     } else {
       logger("XX Fallback Stage 0 - Responder waiting to receive first message...");
-      const receivedMessageBuffer = decodeMessageBuffer(this.initialMsg);
+      const receivedMessageBuffer = decode0(this.initialMsg);
       console.log("receivedMessageBuffer: ", receivedMessageBuffer)
       this.xx.recvMessage(this.session, {
         ne: receivedMessageBuffer.ne,
@@ -58,7 +58,7 @@ export class Handshake extends XXHandshake {
   public async exchange(): Promise<void> {
     if (this.isInitiator) {
       logger('XX Fallback Stage 1 - Initiator waiting to receive first message from responder...');
-      const receivedMessageBuffer = decodeMessageBuffer(this.initialMsg);
+      const receivedMessageBuffer = decode1(this.initialMsg);
       const plaintext = this.xx.recvMessage(this.session, receivedMessageBuffer);
       logger('XX Fallback Stage 1 - Initiator received the message. Got remote\'s static key.');
 
@@ -81,7 +81,7 @@ export class Handshake extends XXHandshake {
       );
 
       const messageBuffer = this.xx.sendMessage(this.session, handshakePayload);
-      this.connection.writeLP(encodeMessageBuffer(messageBuffer));
+      this.connection.writeLP(encode1(messageBuffer));
       logger('Stage 1 - Responder sent the second handshake message with signed payload.')
     }
   }

src/handshake-xx.ts

@@ -13,7 +13,7 @@ import {
   verifySignedPayload,
 } from "./utils";
 import { logger } from "./logger";
-import { decodeMessageBuffer, encodeMessageBuffer } from "./encoder";
+import { decode0, decode1, encode0, encode1 } from "./encoder";
 import { WrappedConnection } from "./noise";
 
 export class Handshake implements HandshakeInterface {
@@ -56,11 +56,11 @@ export class Handshake implements HandshakeInterface {
     if (this.isInitiator) {
       logger("Stage 0 - Initiator starting to send first message.");
       const messageBuffer = this.xx.sendMessage(this.session, Buffer.alloc(0));
-      this.connection.writeLP(encodeMessageBuffer(messageBuffer));
+      this.connection.writeLP(encode0(messageBuffer));
       logger("Stage 0 - Initiator finished sending first message.");
     } else {
       logger("Stage 0 - Responder waiting to receive first message...");
-      const receivedMessageBuffer = decodeMessageBuffer((await this.connection.readLP()).slice());
+      const receivedMessageBuffer = decode0((await this.connection.readLP()).slice());
       this.xx.recvMessage(this.session, receivedMessageBuffer);
       logger("Stage 0 - Responder received first message.");
     }
@@ -70,7 +70,7 @@ export class Handshake implements HandshakeInterface {
   public async exchange(): Promise<void> {
     if (this.isInitiator) {
       logger('Stage 1 - Initiator waiting to receive first message from responder...');
-      const receivedMessageBuffer = decodeMessageBuffer((await this.connection.readLP()).slice());
+      const receivedMessageBuffer = decode1((await this.connection.readLP()).slice());
       const plaintext = this.xx.recvMessage(this.session, receivedMessageBuffer);
       logger('Stage 1 - Initiator received the message. Got remote\'s static key.');
 
@@ -93,7 +93,7 @@ export class Handshake implements HandshakeInterface {
       );
 
       const messageBuffer = this.xx.sendMessage(this.session, handshakePayload);
-      this.connection.writeLP(encodeMessageBuffer(messageBuffer));
+      this.connection.writeLP(encode1(messageBuffer));
       logger('Stage 1 - Responder sent the second handshake message with signed payload.')
     }
   }
@@ -111,11 +111,11 @@ export class Handshake implements HandshakeInterface {
         signedEarlyDataPayload
       );
       const messageBuffer = this.xx.sendMessage(this.session, handshakePayload);
-      this.connection.writeLP(encodeMessageBuffer(messageBuffer));
+      this.connection.writeLP(encode1(messageBuffer));
       logger('Stage 2 - Initiator sent message with signed payload.');
     } else {
       logger('Stage 2 - Responder waiting for third handshake message...');
-      const receivedMessageBuffer = decodeMessageBuffer((await this.connection.readLP()).slice());
+      const receivedMessageBuffer = decode1((await this.connection.readLP()).slice());
       const plaintext = this.xx.recvMessage(this.session, receivedMessageBuffer);
       logger('Stage 2 - Responder received the message, finished handshake. Got remote\'s static key.');
 

src/handshakes/xx.ts

@@ -199,28 +199,4 @@ export class XX extends AbstractHandshake {
     session.mc = session.mc.add(new BN(1));
     return plaintext;
   }
-
-  public decode0(input: bytes): MessageBuffer {
-    if (input.length < 32) {
-      throw new Error("Cannot decode stage 0 MessageBuffer: length less than 32 bytes.");
-    }
-
-    return {
-      ne: input.slice(0, 32),
-      ciphertext: input.slice(32, input.length),
-      ns: Buffer.alloc(0),
-    }
-  }
-
-  public decode1(input: bytes): MessageBuffer {
-    if (input.length < 96) {
-      throw new Error("Cannot decode stage 0 MessageBuffer: length less than 96 bytes.");
-    }
-
-    return {
-      ne: input.slice(0, 32),
-      ns: input.slice(32, 80),
-      ciphertext: input.slice(80, input.length),
-    }
-  }
 }