142 lines
6.0 KiB
JavaScript
142 lines
6.0 KiB
JavaScript
import { createCipheriv, createDecipheriv, createHash, createHmac, randomBytes } from 'crypto';
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import * as curve from 'libsignal/src/curve.js';
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import { KEY_BUNDLE_TYPE } from '../Defaults/index.js';
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// insure browser & node compatibility
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const { subtle } = globalThis.crypto;
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/** prefix version byte to the pub keys, required for some curve crypto functions */
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export const generateSignalPubKey = (pubKey) => pubKey.length === 33 ? pubKey : Buffer.concat([KEY_BUNDLE_TYPE, pubKey]);
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export const Curve = {
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generateKeyPair: () => {
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const { pubKey, privKey } = curve.generateKeyPair();
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return {
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private: Buffer.from(privKey),
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// remove version byte
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public: Buffer.from(pubKey.slice(1))
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};
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},
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sharedKey: (privateKey, publicKey) => {
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const shared = curve.calculateAgreement(generateSignalPubKey(publicKey), privateKey);
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return Buffer.from(shared);
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},
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sign: (privateKey, buf) => curve.calculateSignature(privateKey, buf),
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verify: (pubKey, message, signature) => {
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try {
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curve.verifySignature(generateSignalPubKey(pubKey), message, signature);
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return true;
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}
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catch (error) {
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return false;
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}
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}
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};
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export const signedKeyPair = (identityKeyPair, keyId) => {
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const preKey = Curve.generateKeyPair();
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const pubKey = generateSignalPubKey(preKey.public);
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const signature = Curve.sign(identityKeyPair.private, pubKey);
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return { keyPair: preKey, signature, keyId };
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};
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const GCM_TAG_LENGTH = 128 >> 3;
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/**
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* encrypt AES 256 GCM;
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* where the tag tag is suffixed to the ciphertext
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* */
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export function aesEncryptGCM(plaintext, key, iv, additionalData) {
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const cipher = createCipheriv('aes-256-gcm', key, iv);
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cipher.setAAD(additionalData);
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return Buffer.concat([cipher.update(plaintext), cipher.final(), cipher.getAuthTag()]);
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}
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/**
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* decrypt AES 256 GCM;
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* where the auth tag is suffixed to the ciphertext
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* */
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export function aesDecryptGCM(ciphertext, key, iv, additionalData) {
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const decipher = createDecipheriv('aes-256-gcm', key, iv);
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// decrypt additional adata
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const enc = ciphertext.slice(0, ciphertext.length - GCM_TAG_LENGTH);
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const tag = ciphertext.slice(ciphertext.length - GCM_TAG_LENGTH);
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// set additional data
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decipher.setAAD(additionalData);
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decipher.setAuthTag(tag);
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return Buffer.concat([decipher.update(enc), decipher.final()]);
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}
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export function aesEncryptCTR(plaintext, key, iv) {
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const cipher = createCipheriv('aes-256-ctr', key, iv);
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return Buffer.concat([cipher.update(plaintext), cipher.final()]);
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}
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export function aesDecryptCTR(ciphertext, key, iv) {
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const decipher = createDecipheriv('aes-256-ctr', key, iv);
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return Buffer.concat([decipher.update(ciphertext), decipher.final()]);
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}
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/** decrypt AES 256 CBC; where the IV is prefixed to the buffer */
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export function aesDecrypt(buffer, key) {
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return aesDecryptWithIV(buffer.slice(16, buffer.length), key, buffer.slice(0, 16));
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}
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/** decrypt AES 256 CBC */
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export function aesDecryptWithIV(buffer, key, IV) {
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const aes = createDecipheriv('aes-256-cbc', key, IV);
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return Buffer.concat([aes.update(buffer), aes.final()]);
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}
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// encrypt AES 256 CBC; where a random IV is prefixed to the buffer
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export function aesEncrypt(buffer, key) {
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const IV = randomBytes(16);
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const aes = createCipheriv('aes-256-cbc', key, IV);
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return Buffer.concat([IV, aes.update(buffer), aes.final()]); // prefix IV to the buffer
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}
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// encrypt AES 256 CBC with a given IV
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export function aesEncrypWithIV(buffer, key, IV) {
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const aes = createCipheriv('aes-256-cbc', key, IV);
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return Buffer.concat([aes.update(buffer), aes.final()]); // prefix IV to the buffer
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}
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// sign HMAC using SHA 256
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export function hmacSign(buffer, key, variant = 'sha256') {
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return createHmac(variant, key).update(buffer).digest();
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}
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export function sha256(buffer) {
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return createHash('sha256').update(buffer).digest();
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}
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export function md5(buffer) {
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return createHash('md5').update(buffer).digest();
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}
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// HKDF key expansion
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export async function hkdf(buffer, expandedLength, info) {
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// Normalize to a Uint8Array whose underlying buffer is a regular ArrayBuffer (not ArrayBufferLike)
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// Cloning via new Uint8Array(...) guarantees the generic parameter is ArrayBuffer which satisfies WebCrypto types.
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const inputKeyMaterial = new Uint8Array(buffer instanceof Uint8Array ? buffer : new Uint8Array(buffer));
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// Set default values if not provided
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const salt = info.salt ? new Uint8Array(info.salt) : new Uint8Array(0);
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const infoBytes = info.info ? new TextEncoder().encode(info.info) : new Uint8Array(0);
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// Import the input key material (cast to BufferSource to appease TS DOM typings)
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const importedKey = await subtle.importKey('raw', inputKeyMaterial, { name: 'HKDF' }, false, [
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'deriveBits'
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]);
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// Derive bits using HKDF
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const derivedBits = await subtle.deriveBits({
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name: 'HKDF',
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hash: 'SHA-256',
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salt: salt,
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info: infoBytes
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}, importedKey, expandedLength * 8 // Convert bytes to bits
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);
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return Buffer.from(derivedBits);
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}
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export async function derivePairingCodeKey(pairingCode, salt) {
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// Convert inputs to formats Web Crypto API can work with
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const encoder = new TextEncoder();
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const pairingCodeBuffer = encoder.encode(pairingCode);
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const saltBuffer = new Uint8Array(salt instanceof Uint8Array ? salt : new Uint8Array(salt));
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// Import the pairing code as key material
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const keyMaterial = await subtle.importKey('raw', pairingCodeBuffer, { name: 'PBKDF2' }, false, [
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'deriveBits'
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]);
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// Derive bits using PBKDF2 with the same parameters
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// 2 << 16 = 131,072 iterations
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const derivedBits = await subtle.deriveBits({
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name: 'PBKDF2',
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salt: saltBuffer,
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iterations: 2 << 16,
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hash: 'SHA-256'
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}, keyMaterial, 32 * 8 // 32 bytes * 8 = 256 bits
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);
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return Buffer.from(derivedBits);
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}
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//# sourceMappingURL=crypto.js.map
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