a4b25f7df1
Sadly, we are not quite compliant with the WC3 webcrypto spec due to our insistance on passing around key data in plain old ArrayBuffers. Also converted whitespace.
102 lines
4.3 KiB
JavaScript
102 lines
4.3 KiB
JavaScript
/* vim: ts=4:sw=4:expandtab
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/* Web Crypto polyfill. TODO: replace with web crypto */
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// All inputs/outputs are arraybuffers!
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window.crypto.subtle = (function() {
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/* if (window.crypto.subtle !== undefined && window.crypto.subtle !== null) {
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return window.crypto.subtle;
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} else*/ {
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var StaticArrayBufferProto = new ArrayBuffer().__proto__;
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function assertIsArrayBuffer(thing) {
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if (thing !== Object(thing) || thing.__proto__ != StaticArrayBufferProto)
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throw new Error("Needed a ArrayBuffer");
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}
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// private implementation functions
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function HmacSHA256(key, input) {
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assertIsArrayBuffer(key);
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assertIsArrayBuffer(input);
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return CryptoJS.HmacSHA256(
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CryptoJS.lib.WordArray.create(toArrayBuffer(input)),
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CryptoJS.enc.Latin1.parse(getString(key))
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).toString(CryptoJS.enc.Latin1);
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};
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function encryptAESCTR(plaintext, key, counter) {
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assertIsArrayBuffer(plaintext);
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assertIsArrayBuffer(key);
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assertIsArrayBuffer(counter);
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return CryptoJS.AES.encrypt(CryptoJS.enc.Latin1.parse(getString(plaintext)),
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CryptoJS.enc.Latin1.parse(getString(key)),
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{mode: CryptoJS.mode.CTR, iv: CryptoJS.enc.Latin1.parse(getString(counter)),
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padding: CryptoJS.pad.NoPadding})
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.ciphertext.toString(CryptoJS.enc.Latin1);
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};
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function decryptAESCTR(ciphertext, key, counter) {
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assertIsArrayBuffer(ciphertext);
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assertIsArrayBuffer(key);
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assertIsArrayBuffer(counter);
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return CryptoJS.AES.decrypt(btoa(getString(ciphertext)),
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CryptoJS.enc.Latin1.parse(getString(key)),
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{mode: CryptoJS.mode.CTR, iv: CryptoJS.enc.Latin1.parse(getString(counter)),
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padding: CryptoJS.pad.NoPadding})
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.toString(CryptoJS.enc.Latin1);
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};
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function decryptAESCBC(ciphertext, key, iv) {
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assertIsArrayBuffer(ciphertext);
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assertIsArrayBuffer(key);
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assertIsArrayBuffer(iv);
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return CryptoJS.AES.decrypt(btoa(getString(ciphertext)),
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CryptoJS.enc.Latin1.parse(getString(key)),
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{iv: CryptoJS.enc.Latin1.parse(getString(iv))})
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.toString(CryptoJS.enc.Latin1);
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};
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// utility function for connecting front and back ends via promises
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// Takes an implementation function and 0 or more arguments
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function promise(implementation) {
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var args = Array.prototype.slice.call(arguments);
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args.shift();
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return Promise.resolve(toArrayBuffer(implementation.apply(this, args)));
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}
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// public interface functions
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function encrypt(algorithm, key, data) {
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if (algorithm.name === "AES-CTR")
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return promise(encryptAESCTR, data, key, algorithm.counter);
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};
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function decrypt(algorithm, key, data) {
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if (algorithm.name === "AES-CTR")
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return promise(decryptAESCTR, data, key, algorithm.counter);
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if (algorithm.name === "AES-CBC")
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return promise(decryptAESCBC, data, key, algorithm.iv);
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};
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function sign(algorithm, key, data) {
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if (algorithm.name === "HMAC" && algorithm.hash === "SHA-256")
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return promise(HmacSHA256, key, data);
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};
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return {
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encrypt : encrypt,
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decrypt : decrypt,
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sign : sign,
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}
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}
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})();
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