@periskope/baileys
Version:
WhatsApp API
85 lines • 4.24 kB
JavaScript
import { decrypt, encrypt } from 'libsignal/src/crypto.js';
import { SenderKeyMessage } from './sender-key-message.js';
import { SenderKeyName } from './sender-key-name.js';
import { SenderKeyRecord } from './sender-key-record.js';
import { SenderKeyState } from './sender-key-state.js';
export class GroupCipher {
constructor(senderKeyStore, senderKeyName) {
this.senderKeyStore = senderKeyStore;
this.senderKeyName = senderKeyName;
}
async encrypt(paddedPlaintext) {
const record = await this.senderKeyStore.loadSenderKey(this.senderKeyName);
if (!record) {
throw new Error('No SenderKeyRecord found for encryption');
}
const senderKeyState = record.getSenderKeyState();
if (!senderKeyState) {
throw new Error('No session to encrypt message');
}
const iteration = senderKeyState.getSenderChainKey().getIteration();
const senderKey = this.getSenderKey(senderKeyState, iteration === 0 ? 0 : iteration + 1);
const ciphertext = await this.getCipherText(senderKey.getIv(), senderKey.getCipherKey(), paddedPlaintext);
const senderKeyMessage = new SenderKeyMessage(senderKeyState.getKeyId(), senderKey.getIteration(), ciphertext, senderKeyState.getSigningKeyPrivate());
await this.senderKeyStore.storeSenderKey(this.senderKeyName, record);
return senderKeyMessage.serialize();
}
async decrypt(senderKeyMessageBytes) {
const record = await this.senderKeyStore.loadSenderKey(this.senderKeyName);
if (!record) {
throw new Error('No SenderKeyRecord found for decryption');
}
const senderKeyMessage = new SenderKeyMessage(null, null, null, null, senderKeyMessageBytes);
const senderKeyState = record.getSenderKeyState(senderKeyMessage.getKeyId());
if (!senderKeyState) {
throw new Error('No session found to decrypt message');
}
senderKeyMessage.verifySignature(senderKeyState.getSigningKeyPublic());
const senderKey = this.getSenderKey(senderKeyState, senderKeyMessage.getIteration());
const plaintext = await this.getPlainText(senderKey.getIv(), senderKey.getCipherKey(), senderKeyMessage.getCipherText());
await this.senderKeyStore.storeSenderKey(this.senderKeyName, record);
return plaintext;
}
getSenderKey(senderKeyState, iteration) {
let senderChainKey = senderKeyState.getSenderChainKey();
if (senderChainKey.getIteration() > iteration) {
if (senderKeyState.hasSenderMessageKey(iteration)) {
const messageKey = senderKeyState.removeSenderMessageKey(iteration);
if (!messageKey) {
throw new Error('No sender message key found for iteration');
}
return messageKey;
}
throw new Error(`Received message with old counter: ${senderChainKey.getIteration()}, ${iteration}`);
}
if (iteration - senderChainKey.getIteration() > 2000) {
throw new Error('Over 2000 messages into the future!');
}
while (senderChainKey.getIteration() < iteration) {
senderKeyState.addSenderMessageKey(senderChainKey.getSenderMessageKey());
senderChainKey = senderChainKey.getNext();
}
senderKeyState.setSenderChainKey(senderChainKey.getNext());
return senderChainKey.getSenderMessageKey();
}
async getPlainText(iv, key, ciphertext) {
try {
return decrypt(key, ciphertext, iv);
}
catch (e) {
throw new Error('InvalidMessageException');
}
}
async getCipherText(iv, key, plaintext) {
try {
const ivBuffer = typeof iv === 'string' ? Buffer.from(iv, 'base64') : iv;
const keyBuffer = typeof key === 'string' ? Buffer.from(key, 'base64') : key;
const plaintextBuffer = typeof plaintext === 'string' ? Buffer.from(plaintext) : plaintext;
return encrypt(keyBuffer, plaintextBuffer, ivBuffer);
}
catch (e) {
throw new Error('InvalidMessageException');
}
}
}
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