/// <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);
}
