Merge branch 'wes-no-encryption'

README.md

@@ -6,6 +6,7 @@
 
 This is a JS library that implements TCP network control for LG TVs manufactured
 since 2018. It utilizes encryption rules based on a guide found on the internet.
+A non-encrypted mode is provided for older models, but hasn't been tested.
 
 This is not provided by LG, and it is not a complete implementation for every TV
 model.
@@ -85,7 +86,8 @@ const lgtv = new LGTV(
   '1a:2b:3c:4d:5e:6f',
 
   /**
-   * Encryption Keycode, as generated during "Setting Up the TV" above
+   * Encryption Keycode, as generated during "Setting Up the TV" above.
+   * If not provided, uses clear text, but is required by most models.
    */
   'KEY1C0DE',
 

src/classes/LGEncryption.ts

@@ -15,107 +15,127 @@ export interface EncryptionSettings {
   responseTerminator: string;
 }
 
-function assertSettings(settings: EncryptionSettings) {
-  assert(
-    typeof settings === 'object' && settings !== null,
-    'settings must be an object',
-  );
-
-  const {
-    encryptionIvLength,
-    encryptionKeyDigest,
-    encryptionKeyIterations,
-    encryptionKeyLength,
-    encryptionKeySalt,
-    keycodeFormat,
-    messageBlockSize,
-    messageTerminator,
-    responseTerminator,
-  } = settings;
-  assert(
-    typeof encryptionIvLength === 'number' && encryptionIvLength > 0,
-    'settings.encryptionIvLength must be a number greater than 0',
-  );
-  assert(
-    typeof encryptionKeyDigest === 'string' && encryptionKeyDigest.length > 0,
-    'settings.encryptionKeyDigest must be a string with length greater than 0',
-  );
-  assert(
-    typeof encryptionKeyIterations === 'number' && encryptionKeyIterations > 0,
-    'settings.encryptionKLeyIterations must be a number greater than 0',
-  );
-  assert(
-    typeof encryptionKeyLength === 'number' && encryptionKeyLength > 0,
-    'settings.encryptionKeyLength must be a number greater than 0',
-  );
-  assert(
-    Array.isArray(encryptionKeySalt) &&
-      encryptionKeySalt.some((data) => typeof data === 'number' && data > 0),
-    'settings.encryptionKeySalt must be an array of numbers with length greater than 0',
-  );
-  assert(
-    keycodeFormat instanceof RegExp,
-    'settings.keycodeFormat must be an instance of RegExp',
-  );
-  assert(
-    typeof messageBlockSize === 'number' && messageBlockSize > 0,
-    'settings.messageBlockSize must be a number greater than 0',
-  );
-  assert(
-    typeof messageTerminator === 'string' && messageTerminator.length > 0,
-    'settings.messageTerminator must be a string with length greater than 0',
-  );
-  assert(
-    typeof responseTerminator === 'string' && responseTerminator.length > 0,
-    'settings.responseTerminator must be a string with length greater than 0',
-  );
-}
+export class LGEncoder {
+  constructor(protected settings: EncryptionSettings = DefaultSettings) {
+    assert(
+      typeof settings === 'object' && settings !== null,
+      'settings must be an object',
+    );
 
-function deriveKey(keycode: string, settings = DefaultSettings) {
-  assertSettings(settings);
-  assert(typeof keycode === 'string', 'keycode must be a string');
-  assert(settings.keycodeFormat.test(keycode), 'keycode format is invalid');
-
-  return pbkdf2Sync(
-    keycode,
-    Buffer.from(settings.encryptionKeySalt),
-    settings.encryptionKeyIterations,
-    settings.encryptionKeyLength,
-    settings.encryptionKeyDigest,
-  );
-}
+    const { messageBlockSize, messageTerminator, responseTerminator } =
+      settings;
+    assert(
+      typeof messageBlockSize === 'number' && messageBlockSize > 0,
+      'settings.messageBlockSize must be a number greater than 0',
+    );
+    assert(
+      typeof messageTerminator === 'string' && messageTerminator.length > 0,
+      'settings.messageTerminator must be a string with length greater than 0',
+    );
+    assert(
+      typeof responseTerminator === 'string' && responseTerminator.length > 0,
+      'settings.responseTerminator must be a string with length greater than 0',
+    );
+  }
 
-function generateRandomIv(length = DefaultSettings.encryptionIvLength) {
-  assert(typeof length === 'number', 'length must be a number');
-  assert(length > 0, 'length must be greater than 0');
+  protected terminateMessage(message: string): string {
+    const { messageTerminator } = this.settings;
+    assert(typeof message === 'string', 'message must be a string');
+    assert(message.length > 0, 'message must have a length greater than 0');
+    assert(
+      !message.includes(messageTerminator),
+      'message must not include the message terminator character',
+    );
+    return message + messageTerminator;
+  }
+
+  protected stripEnd(message: string): string {
+    const { responseTerminator } = this.settings;
+    return message.substring(0, message.indexOf(responseTerminator));
+  }
+
+  encode(message: string): Buffer {
+    return Buffer.from(this.terminateMessage(message), 'utf8');
+  }
 
-  const iv = Buffer.alloc(length, 0);
-  for (let i = 0; i < length; i++) {
-    iv[i] = Math.floor(Math.random() * 255);
+  decode(data: Buffer): string {
+    return this.stripEnd(data.toString());
   }
-  return iv;
 }
 
-export class LGEncryption {
+export class LGEncryption extends LGEncoder {
   private derivedKey: Buffer;
 
-  constructor(keycode: string, private settings = DefaultSettings) {
-    assertSettings(settings);
-    this.derivedKey = deriveKey(keycode, settings);
-  }
+  constructor(keycode: string, settings: EncryptionSettings = DefaultSettings) {
+    super(settings);
+
+    const {
+      encryptionIvLength,
+      encryptionKeyDigest,
+      encryptionKeyIterations,
+      encryptionKeyLength,
+      encryptionKeySalt,
+      keycodeFormat,
+    } = settings;
+    assert(
+      typeof encryptionIvLength === 'number' && encryptionIvLength > 0,
+      'settings.encryptionIvLength must be a number greater than 0',
+    );
+    assert(
+      typeof encryptionKeyDigest === 'string' && encryptionKeyDigest.length > 0,
+      'settings.encryptionKeyDigest must be a string with length greater than 0',
+    );
+    assert(
+      typeof encryptionKeyIterations === 'number' &&
+        encryptionKeyIterations > 0,
+      'settings.encryptionKLeyIterations must be a number greater than 0',
+    );
+    assert(
+      typeof encryptionKeyLength === 'number' && encryptionKeyLength > 0,
+      'settings.encryptionKeyLength must be a number greater than 0',
+    );
+    assert(
+      Array.isArray(encryptionKeySalt) &&
+        encryptionKeySalt.some((data) => typeof data === 'number' && data > 0),
+      'settings.encryptionKeySalt must be an array of numbers with length greater than 0',
+    );
+    assert(
+      keycodeFormat instanceof RegExp,
+      'settings.keycodeFormat must be an instance of RegExp',
+    );
 
-  private prepareMessage(message: string) {
-    assert(typeof message === 'string', 'message must be a string');
-    assert(message.length > 0, 'message must have a length greater than 0');
+    this.derivedKey = this.deriveKey(keycode);
+  }
 
-    const { messageTerminator, messageBlockSize } = this.settings;
+  private deriveKey(keycode: string) {
+    assert(typeof keycode === 'string', 'keycode must be a string');
     assert(
-      !message.includes(messageTerminator),
-      'message must not include the message terminator character',
+      this.settings.keycodeFormat.test(keycode),
+      'keycode format is invalid',
     );
 
-    let newMessage = message + messageTerminator;
-    if (newMessage.length % messageBlockSize === 0) {
+    return pbkdf2Sync(
+      keycode,
+      Buffer.from(this.settings.encryptionKeySalt),
+      this.settings.encryptionKeyIterations,
+      this.settings.encryptionKeyLength,
+      this.settings.encryptionKeyDigest,
+    );
+  }
+
+  private generateRandomIv() {
+    const { encryptionIvLength } = this.settings;
+    const iv = Buffer.alloc(encryptionIvLength, 0);
+    for (let i = 0; i < encryptionIvLength; i++) {
+      iv[i] = Math.floor(Math.random() * 255);
+    }
+    return iv;
+  }
+
+  protected padMessage(message: string): string {
+    const { messageBlockSize } = this.settings;
+    let newMessage = message;
+    if (message.length % messageBlockSize === 0) {
       newMessage += ' ';
     }
 
@@ -124,13 +144,12 @@ export class LGEncryption {
       const padding = messageBlockSize - remainder;
       newMessage += String.fromCharCode(padding).repeat(padding);
     }
-
     return newMessage;
   }
 
-  encrypt(message: string) {
-    const iv = generateRandomIv(this.settings.encryptionKeyLength);
-    const preparedMessage = this.prepareMessage(message);
+  encode(message: string): Buffer {
+    const iv = this.generateRandomIv();
+    const paddedMessage = this.padMessage(this.terminateMessage(message));
 
     const ecbCypher = createCipheriv(
       'aes-128-ecb',
@@ -140,30 +159,24 @@ export class LGEncryption {
     const ivEnc = ecbCypher.update(iv);
 
     const cbcCypher = createCipheriv('aes-128-cbc', this.derivedKey, iv);
-    const dataEnc = cbcCypher.update(preparedMessage, 'utf8');
+    const dataEnc = cbcCypher.update(paddedMessage);
 
     return Buffer.concat([ivEnc, dataEnc]);
   }
 
-  decrypt(cipher: Buffer) {
+  decode(cipher: Buffer): string {
+    const { encryptionKeyLength } = this.settings;
     const ecbDecypher = createDecipheriv(
       'aes-128-ecb',
       this.derivedKey,
       Buffer.alloc(0),
     );
     ecbDecypher.setAutoPadding(false);
-    const iv = ecbDecypher.update(
-      cipher.slice(0, this.settings.encryptionKeyLength),
-    );
+    const iv = ecbDecypher.update(cipher.slice(0, encryptionKeyLength));
 
     const cbcDecypher = createDecipheriv('aes-128-cbc', this.derivedKey, iv);
     cbcDecypher.setAutoPadding(false);
-    const decrypted = cbcDecypher
-      .update(cipher.slice(this.settings.encryptionKeyLength))
-      .toString();
-    return decrypted.substring(
-      0,
-      decrypted.indexOf(this.settings.responseTerminator),
-    );
+    const decrypted = cbcDecypher.update(cipher.slice(encryptionKeyLength));
+    return this.stripEnd(decrypted.toString());
   }
 }

src/classes/LGTV.ts

@@ -9,7 +9,7 @@ import {
   PictureModes,
   ScreenMuteModes,
 } from '../constants/TV.js';
-import { LGEncryption } from './LGEncryption.js';
+import { LGEncoder, LGEncryption } from './LGEncryption.js';
 import { TinySocket } from './TinySocket.js';
 
 export class ResponseParseError extends Error {}
@@ -20,23 +20,25 @@ function throwIfNotOK(response: string) {
 }
 
 export class LGTV {
-  encryption: LGEncryption;
+  encoder: LGEncoder;
   socket: TinySocket;
 
   constructor(
     host: string,
     macAddress: string | null,
-    keycode: string,
+    keycode: string | null,
     settings = DefaultSettings,
   ) {
     this.socket = new TinySocket(host, macAddress, settings);
-    this.encryption = new LGEncryption(keycode, settings);
+    this.encoder = keycode
+      ? new LGEncryption(keycode, settings)
+      : new LGEncoder(settings);
   }
 
   private async sendCommand(command: string) {
-    const encryptedData = this.encryption.encrypt(command);
-    const encryptedResponse = await this.socket.sendReceive(encryptedData);
-    return this.encryption.decrypt(encryptedResponse);
+    const request = this.encoder.encode(command);
+    const response = await this.socket.sendReceive(request);
+    return this.encoder.decode(response);
   }
 
   async connect(): Promise<void> {