@baileys-md/baileys/lib/Signal/Group/sender-key-message.js

Baileys WhatsApp API

//========================================//
 
import { calculateSignature, verifySignature } from "libsignal-xeuka/src/curve.js";
import { CiphertextMessage } from "./ciphertext-message.js";
import { proto } from "../../../WAProto/index.js";

export class SenderKeyMessage extends CiphertextMessage {
  constructor(keyId, iteration, ciphertext, signatureKey, serialized) {
    super();
    this.SIGNATURE_LENGTH = 64;
    if (serialized) {
      const version = serialized[0];
      const message = serialized.slice(1, serialized.length - this.SIGNATURE_LENGTH);
      const signature = serialized.slice(-1 * this.SIGNATURE_LENGTH);
      const senderKeyMessage = proto.SenderKeyMessage.decode(message).toJSON();
      this.serialized = serialized;
      this.messageVersion = (version & 0xff) >> 4;
      this.keyId = senderKeyMessage.id;
      this.iteration = senderKeyMessage.iteration;
      this.ciphertext =
        typeof senderKeyMessage.ciphertext === "string"
          ? Buffer.from(senderKeyMessage.ciphertext, "base64")
          : senderKeyMessage.ciphertext;
      this.signature = signature;
    }
    else {
      const version = (((this.CURRENT_VERSION << 4) | this.CURRENT_VERSION) & 0xff) % 256;
      const ciphertextBuffer = Buffer.from(ciphertext);
      const message = proto.SenderKeyMessage.encode(proto.SenderKeyMessage.create({
        id: keyId,
        iteration: iteration,
        ciphertext: ciphertextBuffer
      })).finish();
      const signature = this.getSignature(signatureKey, Buffer.concat([Buffer.from([version]), message]));
      this.serialized = Buffer.concat([Buffer.from([version]), message, Buffer.from(signature)]);
      this.messageVersion = this.CURRENT_VERSION;
      this.keyId = keyId;
      this.iteration = iteration;
      this.ciphertext = ciphertextBuffer;
      this.signature = signature;
    }
  }
  getKeyId() {
    return this.keyId;
  }
  getIteration() {
    return this.iteration;
  }
  getCipherText() {
    return this.ciphertext;
  }
  verifySignature(signatureKey) {
    const part1 = this.serialized.slice(0, this.serialized.length - this.SIGNATURE_LENGTH);
    const part2 = this.serialized.slice(-1 * this.SIGNATURE_LENGTH);
    const res = verifySignature(signatureKey, part1, part2);
    if (!res)
      throw new Error("Invalid signature!");
  }
  getSignature(signatureKey, serialized) {
    return Buffer.from(calculateSignature(signatureKey, serialized));
  }
  serialize() {
    return this.serialized;
  }
  getType() {
    return 4;
  }
}