112 lines
4.9 KiB
JavaScript
112 lines
4.9 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.textsecure.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 encryptAESCBC(plaintext, key, iv) {
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assertIsArrayBuffer(plaintext);
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assertIsArrayBuffer(key);
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assertIsArrayBuffer(iv);
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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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{iv: CryptoJS.enc.Latin1.parse(getString(iv))})
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.ciphertext.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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if (algorithm.name === "AES-CBC")
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return promise(encryptAESCBC, data, key, algorithm.iv);
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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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