Files
Baileys/src/Utils/crypto.ts
2022-01-19 15:54:02 +05:30

99 lines
3.2 KiB
TypeScript

import { createCipheriv, createDecipheriv, createHash, createHmac, randomBytes } from 'crypto'
import * as curveJs from 'curve25519-js'
import { KeyPair } from '../Types'
export const Curve = {
generateKeyPair: (): KeyPair => {
const { public: pubKey, private: privKey } = curveJs.generateKeyPair(randomBytes(32))
return {
private: Buffer.from(privKey),
public: Buffer.from(pubKey)
}
},
sharedKey: (privateKey: Uint8Array, publicKey: Uint8Array) => {
const shared = curveJs.sharedKey(privateKey, publicKey)
return Buffer.from(shared)
},
sign: (privateKey: Uint8Array, buf: Uint8Array) => (
Buffer.from(curveJs.sign(privateKey, buf, null))
),
verify: (pubKey: Uint8Array, message: Uint8Array, signature: Uint8Array) => {
return curveJs.verify(pubKey, message, signature)
}
}
export const signedKeyPair = (keyPair: KeyPair, keyId: number) => {
const signKeys = Curve.generateKeyPair()
const pubKey = new Uint8Array(33)
pubKey.set([5], 0)
pubKey.set(signKeys.public, 1)
const signature = Curve.sign(keyPair.private, pubKey)
return { keyPair: signKeys, signature, keyId }
}
/** decrypt AES 256 CBC; where the IV is prefixed to the buffer */
export function aesDecrypt(buffer: Buffer, key: Buffer) {
return aesDecryptWithIV(buffer.slice(16, buffer.length), key, buffer.slice(0, 16))
}
/** decrypt AES 256 CBC */
export function aesDecryptWithIV(buffer: Buffer, key: Buffer, IV: Buffer) {
const aes = createDecipheriv('aes-256-cbc', key, IV)
return Buffer.concat([aes.update(buffer), aes.final()])
}
// encrypt AES 256 CBC; where a random IV is prefixed to the buffer
export function aesEncrypt(buffer: Buffer | Uint8Array, key: Buffer) {
const IV = randomBytes(16)
const aes = createCipheriv('aes-256-cbc', key, IV)
return Buffer.concat([IV, aes.update(buffer), aes.final()]) // prefix IV to the buffer
}
// encrypt AES 256 CBC with a given IV
export function aesEncrypWithIV(buffer: Buffer, key: Buffer, IV: Buffer) {
const aes = createCipheriv('aes-256-cbc', key, IV)
return Buffer.concat([aes.update(buffer), aes.final()]) // prefix IV to the buffer
}
// sign HMAC using SHA 256
export function hmacSign(buffer: Buffer | Uint8Array, key: Buffer | Uint8Array, variant: 'sha256' | 'sha512' = 'sha256') {
return createHmac(variant, key).update(buffer).digest()
}
export function sha256(buffer: Buffer) {
return createHash('sha256').update(buffer).digest()
}
// HKDF key expansion
// from: https://github.com/benadida/node-hkdf
export function hkdf(buffer: Uint8Array, expandedLength: number, { info, salt }: { salt?: Buffer, info?: string }) {
const hashAlg = 'sha256'
const hashLength = 32
salt = salt || Buffer.alloc(hashLength)
// now we compute the PRK
const prk = createHmac(hashAlg, salt).update(buffer).digest()
let prev = Buffer.from([])
const buffers = []
const num_blocks = Math.ceil(expandedLength / hashLength)
const infoBuff = Buffer.from(info || [])
for(var i=0; i<num_blocks; i++) {
const hmac = createHmac(hashAlg, prk)
// XXX is there a more optimal way to build up buffers?
const input = Buffer.concat([
prev,
infoBuff,
Buffer.from(String.fromCharCode(i + 1))
])
hmac.update(input)
prev = hmac.digest()
buffers.push(prev)
}
return Buffer.concat(buffers, expandedLength)
}