Line data    Source code

       1             : /*
       2             :  *   Famedly Matrix SDK
       3             :  *   Copyright (C) 2019, 2020, 2021 Famedly GmbH
       4             :  *
       5             :  *   This program is free software: you can redistribute it and/or modify
       6             :  *   it under the terms of the GNU Affero General Public License as
       7             :  *   published by the Free Software Foundation, either version 3 of the
       8             :  *   License, or (at your option) any later version.
       9             :  *
      10             :  *   This program is distributed in the hope that it will be useful,
      11             :  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
      13             :  *   GNU Affero General Public License for more details.
      14             :  *
      15             :  *   You should have received a copy of the GNU Affero General Public License
      16             :  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
      17             :  */
      18             : 
      19             : import 'dart:convert';
      20             : import 'dart:typed_data';
      21             : 
      22             : import 'package:matrix/encryption/utils/base64_unpadded.dart';
      23             : import 'package:matrix/src/utils/crypto/crypto.dart';
      24             : 
      25             : class EncryptedFile {
      26           2 :   EncryptedFile({
      27             :     required this.data,
      28             :     required this.k,
      29             :     required this.iv,
      30             :     required this.sha256,
      31             :   });
      32             :   Uint8List data;
      33             :   String k;
      34             :   String iv;
      35             :   String sha256;
      36             : }
      37             : 
      38           1 : Future<EncryptedFile> encryptFile(Uint8List input) async {
      39           1 :   final key = secureRandomBytes(32);
      40           1 :   final iv = secureRandomBytes(16);
      41           2 :   final data = await aesCtr.encrypt(input, key, iv);
      42           2 :   final hash = await sha256(data);
      43           1 :   return EncryptedFile(
      44             :     data: data,
      45           2 :     k: base64Url.encode(key).replaceAll('=', ''),
      46           2 :     iv: base64.encode(iv).replaceAll('=', ''),
      47           2 :     sha256: base64.encode(hash).replaceAll('=', ''),
      48             :   );
      49             : }
      50             : 
      51             : /// you would likely want to use [NativeImplementations] and
      52             : /// [Client.nativeImplementations] instead
      53           1 : Future<Uint8List?> decryptFileImplementation(EncryptedFile input) async {
      54           5 :   if (base64.encode(await sha256(input.data)) !=
      55           2 :       base64.normalize(input.sha256)) {
      56             :     return null;
      57             :   }
      58             : 
      59           3 :   final key = base64decodeUnpadded(base64.normalize(input.k));
      60           3 :   final iv = base64decodeUnpadded(base64.normalize(input.iv));
      61           3 :   return await aesCtr.encrypt(input.data, key, iv);
      62             : }