Coverage Summary for Class: KeyCrypterAes (co.rsk.crypto)

Class Class, % Method, % Line, %
KeyCrypterAes 100% (1/1) 100% (4/4) 85.2% (23/27)


1 /* 2  * This file is part of RskJ 3  * Copyright (C) 2017 RSK Labs Ltd. 4  * 5  * This program is free software: you can redistribute it and/or modify 6  * it under the terms of the GNU Lesser General Public License as published by 7  * the Free Software Foundation, either version 3 of the License, or 8  * (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 Lesser General Public License for more details. 14  * 15  * You should have received a copy of the GNU Lesser General Public License 16  * along with this program. If not, see <http://www.gnu.org/licenses/>. 17  */ 18  19  20 /* 21  * Copyright 2013 Jim Burton. 22  * Copyright 2014 Andreas Schildbach 23  * 24  * Licensed under the MIT license (the "License") 25  * you may not use this file except in compliance with the License. 26  * You may obtain a copy of the License at 27  * 28  * http://opensource.org/licenses/mit-license.php 29  * 30  * Unless required by applicable law or agreed to in writing, software 31  * distributed under the License is distributed on an "AS IS" BASIS, 32  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 33  * See the License for the specific language governing permissions and 34  * limitations under the License. 35  */ 36  37 package co.rsk.crypto; 38  39 import org.bouncycastle.crypto.BufferedBlockCipher; 40 import org.bouncycastle.crypto.engines.AESEngine; 41 import org.bouncycastle.crypto.modes.CBCBlockCipher; 42 import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher; 43 import org.bouncycastle.crypto.params.KeyParameter; 44 import org.bouncycastle.crypto.params.ParametersWithIV; 45  46 import java.security.SecureRandom; 47 import java.util.Arrays; 48  49 import static com.google.common.base.Preconditions.checkNotNull; 50  51 /** 52  * This class encrypts and decrypts byte arrays using AES symmetric cipher. 53  */ 54 public class KeyCrypterAes implements KeyCrypter { 55  56  /** 57  * The size of an AES block in bytes. 58  * This is also the length of the initialisation vector. 59  */ 60  private static final int BLOCK_LENGTH = 16; // = 128 bits. 61  62  private static final SecureRandom secureRandom = new SecureRandom(); 63  64  /** 65  * Password based encryption using AES - CBC 256 bits. 66  */ 67  @Override 68  public EncryptedData encrypt(byte[] plainBytes, KeyParameter key) { 69  checkNotNull(plainBytes); 70  checkNotNull(key); 71  72  try { 73  // Generate iv - each encryption call has a different iv. 74  byte[] iv = new byte[BLOCK_LENGTH]; 75  secureRandom.nextBytes(iv); 76  77  ParametersWithIV keyWithIv = new ParametersWithIV(key, iv); 78  79  // Encrypt using AES. 80  BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine())); 81  cipher.init(true, keyWithIv); 82  byte[] encryptedBytes = new byte[cipher.getOutputSize(plainBytes.length)]; 83  final int length1 = cipher.processBytes(plainBytes, 0, plainBytes.length, encryptedBytes, 0); 84  final int length2 = cipher.doFinal(encryptedBytes, length1); 85  86  return new EncryptedData(iv, Arrays.copyOf(encryptedBytes, length1 + length2)); 87  } catch (Exception e) { 88  throw new KeyCrypterException("Could not encrypt bytes.", e); 89  } 90  } 91  92  /** 93  * Decrypt bytes previously encrypted with this class. 94  * 95  * @param dataToDecrypt The data to decrypt 96  * @param key The AES key to use for decryption 97  * @return The decrypted bytes 98  * @throws KeyCrypterException if bytes could not be decrypted 99  */ 100  @Override 101  public byte[] decrypt(EncryptedData dataToDecrypt, KeyParameter key) { 102  checkNotNull(dataToDecrypt); 103  checkNotNull(key); 104  105  try { 106  ParametersWithIV keyWithIv = new ParametersWithIV(new KeyParameter(key.getKey()), dataToDecrypt.initialisationVector); 107  108  // Decrypt the message. 109  BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine())); 110  cipher.init(false, keyWithIv); 111  112  byte[] cipherBytes = dataToDecrypt.encryptedBytes; 113  byte[] decryptedBytes = new byte[cipher.getOutputSize(cipherBytes.length)]; 114  final int length1 = cipher.processBytes(cipherBytes, 0, cipherBytes.length, decryptedBytes, 0); 115  final int length2 = cipher.doFinal(decryptedBytes, length1); 116  117  return Arrays.copyOf(decryptedBytes, length1 + length2); 118  } catch (Exception e) { 119  throw new KeyCrypterException("Could not decrypt bytes", e); 120  } 121  } 122 }