mirror of
https://github.com/FranP-code/Baileys.git
synced 2025-10-13 00:32:22 +00:00
refactor: poll decryption
This commit is contained in:
Adhiraj Singh
@@ -15,4 +15,3 @@ export * from './use-multi-file-auth-state'
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export * from './link-preview'
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export * from './event-buffer'
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export * from './process-message'
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export * from './messages-poll'
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@@ -1,139 +0,0 @@
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// original code: https://gist.github.com/PurpShell/44433d21631ff0aefbea57f7b5e31139
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/**
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* Create crypto instance.
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* @description If your nodejs crypto module doesn't have WebCrypto, you must install `@peculiar/webcrypto` first
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* @return {Crypto}
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*/
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export const getCrypto = (): Crypto => {
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const c = require('crypto')
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return 'subtle' in (c?.webcrypto || {}) ? c.webcrypto : new (require('@peculiar/webcrypto').Crypto)()
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}
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/**
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* Compare the SHA-256 hashes of the poll options from the update to find the original choices
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* @param options Options from the poll creation message
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* @param pollOptionHashes hash from `decryptPollMessageRaw()`
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* @return {Promise<string[]>} the original option, can be empty when none are currently selected
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*/
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export const comparePollMessage = async(options: string[], pollOptionHashes: string[]): Promise<string[]> => {
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const selectedOptions: string[] = []
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const crypto = getCrypto()
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for(const option of options) {
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const hash = Buffer
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.from(
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await crypto.subtle.digest(
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'SHA-256',
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(new TextEncoder).encode(option)
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)
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)
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.toString('hex').toUpperCase()
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if(pollOptionHashes.findIndex(h => h === hash) > -1) {
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selectedOptions.push(option)
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}
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}
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;
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return selectedOptions
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}
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/**
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* Raw method to decrypt the message after gathering all information
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* @description Use `decryptPollMessage()` instead, only use this if you know what you are doing
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* @param encPayload Encryption payload/contents want to decrypt, you can get it from `pollUpdateMessage.vote.encPayload`
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* @param encIv Encryption iv (used to decrypt the payload), you can get it from `pollUpdateMessage.vote.encIv`
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* @param additionalData poll Additional data to decrypt poll message
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* @param decryptionKey Generated decryption key to decrypt the poll message
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* @return {Promise<Uint8Array>}
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*/
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const decryptPollMessageInternal = async(
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encPayload: Uint8Array,
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encIv: Uint8Array,
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additionalData: Uint8Array,
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decryptionKey: Uint8Array,
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): Promise<Uint8Array> => {
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const crypto = getCrypto()
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const tagSize_multiplier = 16
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const encoded = encPayload
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const key = await crypto.subtle.importKey('raw', decryptionKey, 'AES-GCM', false, ['encrypt', 'decrypt'])
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const decrypted = await crypto.subtle.decrypt({ name: 'AES-GCM', iv: encIv, additionalData: additionalData, tagLength: 8 * tagSize_multiplier }, key, encoded)
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return new Uint8Array(decrypted).slice(2) // remove 2 bytes (OA20)(space+newline)
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}
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/**
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* Decode the message from `decryptPollMessageInternal()`
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* @param decryptedMessage the message from `decrpytPollMessageInternal()`
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* @return {string}
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*/
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export const decodePollMessage = (decryptedMessage: Uint8Array): string => {
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const n = [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70]
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const outarr: number[] = []
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for(let i = 0; i < decryptedMessage.length; i++) {
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const val = decryptedMessage[i]
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outarr.push(n[val >> 4], n[15 & val])
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}
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return String.fromCharCode(...outarr)
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}
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/**
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* raw function to decrypt a poll message update
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* @param encPayload Encryption payload/contents want to decrypt, you can get it from `pollUpdateMessage.vote.encPayload`
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* @param encIv Encryption iv (used to decrypt the payload), you can get it from `pollUpdateMessage.vote.encIv`
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* @param encKey Encryption key (used to decrypt the payload), you need to store/save the encKey. If you want get the encKey, you could get it from `Message.messageContextInfo.messageSecret`, only available on poll creation message.
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* @param pollMsgSender sender The sender's jid of poll message, you can use `pollUpdateMessage.pollCreationMessageKey.participant` (Note: you need to normalize the jid first)
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* @param pollMsgId The ID of poll message, you can use `pollUpdateMessage.pollMessageCreationKey.id`
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* @param voteMsgSender The poll voter's jid, you can use `Message.key.remoteJid`, `Message.key.participant`, or `Message.participant`. (Note: you need to normalize the jid first)
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* @return {Promise<string[]>} The option or empty array if something went wrong OR everything was unticked
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*/
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export const decryptPollMessageRaw = async(
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encKey: Uint8Array,
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encPayload: Uint8Array,
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encIv: Uint8Array,
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pollMsgSender: string,
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pollMsgId: string,
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voteMsgSender: string
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): Promise<string[]> => {
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const enc = new TextEncoder()
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const crypto = getCrypto()
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const stanzaId = enc.encode(pollMsgId)
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const parentMsgOriginalSender = enc.encode(pollMsgSender)
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const modificationSender = enc.encode(voteMsgSender)
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const modificationType = enc.encode('Poll Vote')
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const pad = new Uint8Array([1])
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const signMe = new Uint8Array([...stanzaId, ...parentMsgOriginalSender, ...modificationSender, ...modificationType, pad] as any)
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const createSignKey = async(n: Uint8Array = new Uint8Array(32)) => {
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return (await crypto.subtle.importKey('raw', n,
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{ 'name': 'HMAC', 'hash': 'SHA-256' }, false, ['sign']
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))
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}
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const sign = async(n: Uint8Array, key: CryptoKey) => {
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return (await crypto.subtle.sign({ 'name': 'HMAC', 'hash': 'SHA-256' }, key, n))
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}
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let key = await createSignKey()
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const temp = await sign(encKey, key)
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key = await createSignKey(new Uint8Array(temp))
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const decryptionKey = new Uint8Array(await sign(signMe, key))
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const additionalData = enc.encode(`${pollMsgId}\u0000${voteMsgSender}`)
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const decryptedMessage = await decryptPollMessageInternal(encPayload, encIv, additionalData, decryptionKey)
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const pollOptionHash = decodePollMessage(decryptedMessage)
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// '0A20' in hex represents unicode " " and "\n" thus declaring the end of one option
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// we want multiple hashes to make it easier to iterate and understand for your use cases
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return pollOptionHash.split('0A20') || []
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}
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@@ -2,8 +2,11 @@ import { AxiosRequestConfig } from 'axios'
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import type { Logger } from 'pino'
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import { proto } from '../../WAProto'
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import { AuthenticationCreds, BaileysEventEmitter, Chat, GroupMetadata, ParticipantAction, SignalKeyStoreWithTransaction, WAMessageStubType } from '../Types'
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import { downloadAndProcessHistorySyncNotification, getContentType, normalizeMessageContent, toNumber } from '../Utils'
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import { getContentType, normalizeMessageContent } from '../Utils/messages'
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import { areJidsSameUser, isJidBroadcast, isJidStatusBroadcast, jidNormalizedUser } from '../WABinary'
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import { aesDecryptGCM, hmacSign } from './crypto'
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import { getKeyAuthor, toNumber } from './generics'
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import { downloadAndProcessHistorySyncNotification } from './history'
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type ProcessMessageContext = {
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shouldProcessHistoryMsg: boolean
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@@ -88,6 +91,51 @@ export const getChatId = ({ remoteJid, participant, fromMe }: proto.IMessageKey)
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return remoteJid!
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}
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type PollContext = {
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/** normalised jid of the person that created the poll */
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pollCreatorJid: string
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/** ID of the poll creation message */
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pollMsgId: string
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/** poll creation message enc key */
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pollEncKey: Uint8Array
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/** jid of the person that voted */
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voterJid: string
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}
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/**
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* Decrypt a poll vote
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* @param vote encrypted vote
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* @param ctx additional info about the poll required for decryption
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* @returns list of SHA256 options
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*/
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export function decryptPollVote(
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{ encPayload, encIv }: proto.Message.IPollEncValue,
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{
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pollCreatorJid,
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pollMsgId,
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pollEncKey,
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voterJid,
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}: PollContext
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) {
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const sign = Buffer.concat(
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[
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toBinary(pollMsgId),
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toBinary(pollCreatorJid),
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toBinary(voterJid),
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toBinary('Poll Vote'),
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new Uint8Array([1])
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]
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)
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const key0 = hmacSign(pollEncKey, new Uint8Array(32), 'sha256')
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const decKey = hmacSign(sign, key0, 'sha256')
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const aad = toBinary(`${pollMsgId}\u0000${voterJid}`)
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const decrypted = aesDecryptGCM(encPayload!, decKey, encIv!, aad)
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return proto.Message.PollVoteMessage.decode(decrypted)
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function toBinary(txt: string) {
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return Buffer.from(txt)
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const processMessage = async(
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message: proto.IWebMessageInfo,
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{
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