DES加密解密!

  public static string Encrypt(string pToEncrypt, string sKey)
        {
            //访问数据加密标准(DES)算法的加密服务提供程序 (CSP) 版本的包装对象
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密对象的密钥和偏移量
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法

            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);//把字符串放到byte数组中

            MemoryStream ms = new MemoryStream();//创建其支持存储区为内存的流　
            //定义将数据流链接到加密转换的流
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            //上面已经完成了把加密后的结果放到内存中去

            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }

        public static string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　//建立加密对象的密钥和偏移量，此值重要，不能修改
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            //建立StringBuild对象，createDecrypt使用的是流对象，必须把解密后的文本变成流对象
            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }

        public string DesDecrypt(string strText, string sDecrKey)
        {
            byte[] byKey = null;
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] inputByteArray = new Byte[strText.Length];
            try
            {
                byKey = System.Text.Encoding.UTF8.GetBytes(sDecrKey.Substring(0, 8));
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                inputByteArray = Convert.FromBase64String(strText);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                System.Text.Encoding encoding = new System.Text.UTF8Encoding();
                return encoding.GetString(ms.ToArray());
            }
            catch (System.Exception error)
            {
                return "error:" + error.Message + "\r";
            }
        }

        public static void EncryptData(string finName, string foutName, byte[] key, byte[] iv)
        {

            FileStream fin = new FileStream(finName, FileMode.Open, FileAccess.Read);

            byte[] buffer = new byte[fin.Length];



            fin.Read(buffer, 0, buffer.Length);

            fin.Flush();

            fin.Close();



            MemoryStream ms = new MemoryStream();

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(key, iv), CryptoStreamMode.Write);



            cs.Write(buffer, 0, buffer.Length);

            cs.FlushFinalBlock();



            byte[] array = ms.ToArray();



            FileStream fout = new FileStream(foutName, FileMode.OpenOrCreate, FileAccess.Write);

            fout.Write(array, 0, array.Length);

            fout.Flush();

            fout.Close();

        }





        public static void DecryptData(string finName, string foutName, byte[] key, byte[] iv)
        {

            FileStream fin = new FileStream(finName, FileMode.Open, FileAccess.Read);



            byte[] buffer = new byte[fin.Length];

            fin.Read(buffer, 0, buffer.Length);

            fin.Flush();

            fin.Close();



            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            MemoryStream ms = new MemoryStream();

            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(key, iv), CryptoStreamMode.Write);

            cs.Write(buffer, 0, buffer.Length);

            cs.FlushFinalBlock();



            byte[] plaintArray = ms.ToArray();



            FileStream fout = new FileStream(foutName, FileMode.OpenOrCreate, FileAccess.Write);

            fout.Write(plaintArray, 0, plaintArray.Length);

            fout.Flush();

            fout.Close();

        }