From a891e0b4eab0e0514bc530b42b767bf768e22521 Mon Sep 17 00:00:00 2001
From: Daniel Huigens <d.huigens@protonmail.com>
Date: Thu, 20 Dec 2018 11:05:04 -0500
Subject: [PATCH] Web Crypto CFB encryption
---
.../sym_encrypted_integrity_protected.js | 27 ++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/src/packet/sym_encrypted_integrity_protected.js b/src/packet/sym_encrypted_integrity_protected.js
index 4362ee5d..6594823c 100644
--- a/src/packet/sym_encrypted_integrity_protected.js
+++ b/src/packet/sym_encrypted_integrity_protected.js
@@ -32,6 +32,7 @@ import crypto from '../crypto';
import enums from '../enums';
import util from '../util';
+const webCrypto = util.getWebCrypto();
const nodeCrypto = util.getNodeCrypto();
const Buffer = util.getNodeBuffer();
@@ -104,7 +105,7 @@ SymEncryptedIntegrityProtected.prototype.encrypt = async function (sessionKeyAlg
tohash = util.concat([tohash, hash]);
if (sessionKeyAlgorithm.substr(0, 3) === 'aes') { // AES optimizations. Native code for node, asmCrypto for browser.
- this.encrypted = aesEncrypt(sessionKeyAlgorithm, util.concat([prefix, tohash]), key);
+ this.encrypted = await aesEncrypt(sessionKeyAlgorithm, util.concat([prefix, tohash]), key);
} else {
tohash = await stream.readToEnd(tohash);
this.encrypted = crypto.cfb.encrypt(prefixrandom, sessionKeyAlgorithm, tohash, key, false);
@@ -168,6 +169,14 @@ export default SymEncryptedIntegrityProtected;
function aesEncrypt(algo, pt, key) {
+ if (
+ util.getWebCrypto() &&
+ key.length !== 24 && // Chrome doesn't support 192 bit keys, see https://www.chromium.org/blink/webcrypto#TOC-AES-support
+ !util.isStream(pt) &&
+ pt.length >= 3000 * config.min_bytes_for_web_crypto // Default to a 3MB minimum. Chrome is pretty slow for small messages, see: https://bugs.chromium.org/p/chromium/issues/detail?id=701188#c2
+ ) { // Web Crypto
+ return webEncrypt(algo, pt, key);
+ }
if (nodeCrypto) { // Node crypto library.
return nodeEncrypt(algo, pt, key);
} // asm.js fallback
@@ -190,6 +199,22 @@ function aesDecrypt(algo, ct, key) {
return stream.slice(pt, crypto.cipher[algo].blockSize + 2); // Remove random prefix
}
+function xorMut(a, b) {
+ for (let i = 0; i < a.length; i++) {
+ a[i] = a[i] ^ b[i];
+ }
+}
+
+async function webEncrypt(algo, pt, key) {
+ const ALGO = 'AES-CBC';
+ const _key = await webCrypto.importKey('raw', key, { name: ALGO }, false, ['encrypt']);
+ const { blockSize } = crypto.cipher[algo];
+ const cbc_pt = util.concatUint8Array([new Uint8Array(blockSize), pt]);
+ const ct = new Uint8Array(await webCrypto.encrypt({ name: ALGO, iv: new Uint8Array(blockSize) }, _key, cbc_pt)).subarray(0, pt.length);
+ xorMut(ct, pt);
+ return ct;
+}
+
function nodeEncrypt(algo, pt, key) {
key = new Buffer(key);
const iv = new Buffer(new Uint8Array(crypto.cipher[algo].blockSize));