C#将字节流加密解密

public class Encrypt
    {
        public static byte[] ToEncrypt(string encryptKey, byte[] P_byte_data)
        {
            try
            {
                byte[] P_byte_key = Encoding.Unicode.GetBytes(encryptKey);//将密钥字符串转换为字节序列
                MemoryStream P_Stream_MS = new MemoryStream(); //创建内存流对象
                CryptoStream P_CryptStream_Stream = new CryptoStream(P_Stream_MS, new DESCryptoServiceProvider().CreateEncryptor(P_byte_key, P_byte_key), CryptoStreamMode.Write);//创建加密流对象
                P_CryptStream_Stream.Write(P_byte_data, 0, P_byte_data.Length);//向加密流中写入字节序列
                P_CryptStream_Stream.FlushFinalBlock();//将数据压入基础流
                byte[] P_bt_temp = P_Stream_MS.ToArray();//从内存流中获取字节序列
                P_CryptStream_Stream.Close();//关闭加密流
                P_Stream_MS.Close();//关闭内存流
                return P_bt_temp;//方法返回加密后的byte 
            }
            catch (CryptographicException ce)
            {
                throw new Exception(ce.Message);
            }
        }

        public static byte[] ToDecrypt(string encryptKey, byte[] P_byte_data)
        {
            try
            {
                byte[] P_byte_key = Encoding.Unicode.GetBytes(encryptKey); //将密钥字符串转换为字节序列
                MemoryStream P_Stream_MS = new MemoryStream(P_byte_data);//创建内存流对象并写入数据
                CryptoStream P_CryptStream_Stream = new CryptoStream(P_Stream_MS, new DESCryptoServiceProvider().CreateDecryptor(P_byte_key, P_byte_key), CryptoStreamMode.Read);//创建加密流对象
                   
                byte[] P_bt_temp = new byte[200];//创建字节序列对象
                MemoryStream P_MemoryStream_temp = new MemoryStream();//创建内存流对象
                    
                int i = 0;//创建记数器
                while ((i = P_CryptStream_Stream.Read(P_bt_temp, 0, P_bt_temp.Length)) > 0)//使用while循环得到解密数据 
                {
                    P_MemoryStream_temp.Write(P_bt_temp, 0, i);//将解密后的数据放入内存流
                        
                }
                return P_MemoryStream_temp.ToArray();//方法返回解密后的byte
                    
            }
            catch (CryptographicException ce)
            {
                throw new Exception(ce.Message);
            }
        }