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Web Crypto CFB encryption

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This commit is contained in:
Daniel Huigens 2018-12-20 11:05:04 -05:00
parent 937150b5bd
commit 3c10c582e2
1 changed files with 26 additions and 1 deletions
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27
src/packet/sym_encrypted_integrity_protected.js
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@ -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));