matrix-js-sdk/lib/utils/encryptAESSecretStorageItem.js

Matrix Client-Server SDK for Javascript

import _asyncToGenerator from "@babel/runtime/helpers/asyncToGenerator";
/*
 * Copyright 2024 The Matrix.org Foundation C.I.C.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { decodeBase64, encodeBase64 } from "../base64.js";
import { deriveKeys } from "./internal/deriveKeys.js";
/**
 * Encrypt a string as a secret storage item, using AES-CTR.
 *
 * @param data - the plaintext to encrypt
 * @param key - the encryption key to use as an input to the HKDF function which is used to derive the AES key for
 *    encryption. Obviously, the same key must be provided when decrypting.
 * @param name - the name of the secret. Used as an input to the HKDF operation which is used to derive the AES key,
 *    so again the same value must be provided when decrypting.
 * @param ivStr - the base64-encoded initialization vector to use. If not supplied, a random one will be generated.
 *
 * @returns The encrypted result, including the ciphertext itself, the initialization vector (as supplied in `ivStr`,
 *   or generated), and an HMAC on the ciphertext — all base64-encoded.
 */
export default function encryptAESSecretStorageItem(_x, _x2, _x3, _x4) {
  return _encryptAESSecretStorageItem.apply(this, arguments);
}
function _encryptAESSecretStorageItem() {
  _encryptAESSecretStorageItem = _asyncToGenerator(function* (data, key, name, ivStr) {
    var iv;
    if (ivStr) {
      iv = decodeBase64(ivStr);
    } else {
      iv = new Uint8Array(16);
      globalThis.crypto.getRandomValues(iv);

      // clear bit 63 of the IV to stop us hitting the 64-bit counter boundary
      // (which would mean we wouldn't be able to decrypt on Android). The loss
      // of a single bit of iv is a price we have to pay.
      iv[8] &= 0x7f;
    }
    var [aesKey, hmacKey] = yield deriveKeys(key, name);
    var encodedData = new TextEncoder().encode(data);
    var ciphertext = yield globalThis.crypto.subtle.encrypt({
      name: "AES-CTR",
      counter: iv,
      length: 64
    }, aesKey, encodedData);
    var hmac = yield globalThis.crypto.subtle.sign({
      name: "HMAC"
    }, hmacKey, ciphertext);
    return {
      iv: encodeBase64(iv),
      ciphertext: encodeBase64(new Uint8Array(ciphertext)),
      mac: encodeBase64(new Uint8Array(hmac))
    };
  });
  return _encryptAESSecretStorageItem.apply(this, arguments);
}
//# sourceMappingURL=encryptAESSecretStorageItem.js.map