signal-desktop/js/webcrypto.js
lilia 9f676af9bb Refactor crypto.js and native client interface
NB: this diff is best viewed with --ignore-whitespace

Distills crypto.js down to the hard cryptoey bones. It pulls from
webcrypto for aes and hmac, and from native client for curve25519 stuff
or potentially another object implementing the handful of needed
curve25519 functions.

Everything else formerly known as crypto, including session storage and
management, axolotl, etc.. is now protocol.js. The separation is not
quite perfect, but it's a big step.

nativeclient.js now enables talking to the native client module through
a high level interface as well as registering callbacks that will be
executed once the module is loaded. And it has tests!

Finally, this commit removes all references to the "testing_only"
object, preferring to run tests on textsecure.crypto instead.
2014-11-06 04:33:43 -08:00

92 lines
4 KiB
JavaScript

/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
'use strict';
;(function() {
// Test for webcrypto support, polyfill if needed.
if (window.crypto.subtle === undefined || window.crypto.subtle === null) {
window.crypto.subtle = (function() {
var StaticArrayBufferProto = new ArrayBuffer().__proto__;
function assertIsArrayBuffer(thing) {
if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
throw new Error("Needed a ArrayBuffer");
}
// Synchronous implementation functions for polyfilling webcrypto
// All inputs/outputs are arraybuffers!
function HmacSHA256(key, input) {
assertIsArrayBuffer(key);
assertIsArrayBuffer(input);
return CryptoJS.HmacSHA256(
CryptoJS.enc.Latin1.parse(getString(input)),
CryptoJS.enc.Latin1.parse(getString(key))
).toString(CryptoJS.enc.Latin1);
};
function encryptAESCBC(plaintext, key, iv) {
assertIsArrayBuffer(plaintext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.encrypt(
CryptoJS.enc.Latin1.parse(getString(plaintext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{ iv: CryptoJS.enc.Latin1.parse(getString(iv)) }
).ciphertext.toString(CryptoJS.enc.Latin1);
};
function decryptAESCBC(ciphertext, key, iv) {
assertIsArrayBuffer(ciphertext);
assertIsArrayBuffer(key);
assertIsArrayBuffer(iv);
return CryptoJS.AES.decrypt(
btoa(getString(ciphertext)),
CryptoJS.enc.Latin1.parse(getString(key)),
{ iv: CryptoJS.enc.Latin1.parse(getString(iv)) }
).toString(CryptoJS.enc.Latin1);
};
// utility function for connecting front and back ends via promises
// Takes an implementation function and 0 or more arguments
function promise(implementation) {
var args = Array.prototype.slice.call(arguments);
args.shift();
return new Promise(function(resolve) {
resolve(toArrayBuffer(implementation.apply(this, args)));
});
};
return {
encrypt: function(algorithm, key, data) {
if (algorithm.name === "AES-CBC")
return promise(encryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
},
decrypt: function(algorithm, key, data) {
if (algorithm.name === "AES-CBC")
return promise(decryptAESCBC, data, key, algorithm.iv.buffer || algorithm.iv);
},
sign: function(algorithm, key, data) {
if (algorithm.name === "HMAC" && algorithm.hash === "SHA-256")
return promise(HmacSHA256, key, data);
},
importKey: function(format, key, algorithm, extractable, usages) {
return new Promise(function(resolve,reject){ resolve(key); });
}
};
})();
} // if !window.crypto.subtle
})();