129 lines
3 KiB
TypeScript
129 lines
3 KiB
TypeScript
// Copyright 2021 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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/* eslint-disable class-methods-use-this */
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import { Buffer } from 'buffer';
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import crypto, { Decipher } from 'crypto';
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import { strictAssert } from '../util/assert';
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import { HashType, CipherType } from '../types/Crypto';
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const AUTH_TAG_SIZE = 16;
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export class Crypto {
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public sign(key: Uint8Array, data: Uint8Array): Uint8Array {
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return crypto
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.createHmac('sha256', Buffer.from(key))
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.update(Buffer.from(data))
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.digest();
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}
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public hash(type: HashType, data: Uint8Array): Uint8Array {
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return crypto.createHash(type).update(Buffer.from(data)).digest();
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}
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public encrypt(
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cipherType: CipherType,
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{
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key,
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plaintext,
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iv,
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aad,
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}: Readonly<{
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key: Uint8Array;
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plaintext: Uint8Array;
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iv: Uint8Array;
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aad?: Uint8Array;
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}>
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): Uint8Array {
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if (cipherType === CipherType.AES256GCM) {
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const gcm = crypto.createCipheriv(
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cipherType,
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Buffer.from(key),
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Buffer.from(iv)
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);
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if (aad) {
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gcm.setAAD(aad);
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}
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const first = gcm.update(Buffer.from(plaintext));
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const last = gcm.final();
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const tag = gcm.getAuthTag();
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strictAssert(tag.length === AUTH_TAG_SIZE, 'Invalid auth tag size');
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return Buffer.concat([first, last, tag]);
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}
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strictAssert(aad === undefined, `AAD is not supported for: ${cipherType}`);
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const cipher = crypto.createCipheriv(
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cipherType,
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Buffer.from(key),
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Buffer.from(iv)
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);
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return Buffer.concat([
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cipher.update(Buffer.from(plaintext)),
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cipher.final(),
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]);
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}
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public decrypt(
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cipherType: CipherType,
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{
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key,
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ciphertext,
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iv,
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aad,
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}: Readonly<{
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key: Uint8Array;
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ciphertext: Uint8Array;
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iv: Uint8Array;
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aad?: Uint8Array;
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}>
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): Uint8Array {
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let decipher: Decipher;
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let input = Buffer.from(ciphertext);
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if (cipherType === CipherType.AES256GCM) {
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const gcm = crypto.createDecipheriv(
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cipherType,
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Buffer.from(key),
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Buffer.from(iv)
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);
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if (input.length < AUTH_TAG_SIZE) {
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throw new Error('Invalid GCM ciphertext');
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}
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const tag = input.slice(input.length - AUTH_TAG_SIZE);
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input = input.slice(0, input.length - AUTH_TAG_SIZE);
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gcm.setAuthTag(tag);
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if (aad) {
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gcm.setAAD(aad);
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}
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decipher = gcm;
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} else {
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strictAssert(
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aad === undefined,
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`AAD is not supported for: ${cipherType}`
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);
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decipher = crypto.createDecipheriv(
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cipherType,
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Buffer.from(key),
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Buffer.from(iv)
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);
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}
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return Buffer.concat([decipher.update(input), decipher.final()]);
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}
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public getRandomBytes(size: number): Uint8Array {
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return crypto.randomBytes(size);
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}
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public constantTimeEqual(left: Uint8Array, right: Uint8Array): boolean {
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return crypto.timingSafeEqual(Buffer.from(left), Buffer.from(right));
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}
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}
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