Cable-Desktop/build/webcrypto.js
lilia 1ad898a62e Simplify webcrypto type conversion
Previously we'd get a WordArray and convert to string before converting
to array buffer. Instead, go directly to array buffer.
2014-11-09 21:52:36 -08:00

99 lines
4.3 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/>.
*/
;(function() {
'use strict';
// 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))
);
};
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;
};
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)) }
);
};
// 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) {
var wordArray = implementation.apply(this, args);
// convert 32bit WordArray to array buffer
var buffer = new ArrayBuffer(wordArray.sigBytes);
var view = new DataView(buffer);
for(var i = 0; i*4 < buffer.byteLength; i++) {
view.setInt32(i*4, wordArray.words[i]);
}
resolve(buffer);
});
};
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
})();