/// <summary> /// 以CBC模式加密明文二进制数组 /// </summary> /// <param name="iv">输出本次加密使用的初始向量。算法会使用Randomizer成员初始化这个数组</param> /// <param name="plain">明文</param> /// <param name="key">密钥</param> /// <returns>加密后的数据块(不包括初始向量)</returns> public static byte[] EncryptCBC(this IBlockEncryption enc, out byte[] iv, byte[] plain, byte[] key) { int BlockSize = enc.BlockSize; byte[] p = enc.Padder(plain); iv = new byte[BlockSize]; enc.Randomizer(iv); Debug.Print(iv.ToHexString()); int block_count = p.Length / BlockSize; for (int i = 0; i < block_count; i++) { int this_block = i * BlockSize; int pre_block = this_block - BlockSize; if (i == 0) { XorBlock(enc, iv, 0, p, this_block); } else { XorBlock(enc, p, pre_block, p, this_block); } enc.Encryptor(p, this_block, key); } return(p); }
/// <summary> /// 以EBC模式解密密文二进制数组 /// </summary> /// <param name="cipher">密文</param> /// <param name="key">密钥</param> /// <returns>明文</returns> public static byte[] DecryptEBC(this IBlockEncryption enc, byte[] cipher, byte[] key) { int BlockSize = enc.BlockSize; byte[] c = (byte[])cipher.Clone(); int block_count = c.Length / BlockSize; for (int i = block_count - 1; i > 0; i--) { enc.Decryptor(c, i * BlockSize, key); } return(c); }
/// <summary> /// 以EBC模式加密明文二进制数组 /// </summary> /// <param name="plain">明文</param> /// <param name="key">密钥</param> /// <returns>密文</returns> public static byte[] EncryptEBC(this IBlockEncryption enc, byte[] plain, byte[] key) { int BlockSize = enc.BlockSize; byte[] p = enc.Padder(plain); int block_count = p.Length / BlockSize; for (int i = 0; i < block_count; i++) { enc.Encryptor(p, i * BlockSize, key); } return(p); }
private static void XorBlock(IBlockEncryption enc, byte[] left, int left_index, byte[] right, int right_index) { int BlockSize = enc.BlockSize; if (left_index + BlockSize > left.Length) { throw new Exception($"异或式的左值长度不足,索引[{left_index}]之后的数据长度不足{BlockSize}"); } else if (right_index + BlockSize > right.Length) { throw new Exception($"异或式的右值长度不足,索引[{right_index}]之后的数据长度不足{BlockSize}"); } for (int i = 0; i < enc.BlockSize; i++) { right[right_index + i] = (byte)(left[left_index + i] ^ right[right_index + i]); } }
/// <summary> /// 以CBC模式解密密文二进制数组 /// </summary> /// <param name="iv">初始向量。用于解密第一个数据块</param> /// <param name="cipher">密文</param> /// <param name="key">密钥</param> /// <returns>解密后的数据块(不包括初始向量)</returns> public static byte[] DecryptCBC(this IBlockEncryption enc, byte[] iv, byte[] cipher, byte[] key) { int BlockSize = enc.BlockSize; byte[] c = (byte[])cipher.Clone(); int block_count = c.Length / BlockSize; for (int i = block_count - 1; i >= 0; i--) { int this_block = i * BlockSize; int pre_block = this_block - BlockSize; enc.Decryptor(c, this_block, key); if (i == 0) { XorBlock(enc, iv, 0, c, this_block); } else { XorBlock(enc, c, pre_block, c, this_block); } } return(c); }