Encrypt and Decrypt

using  System;
using  System.Text;
using  System.Security.Cryptography;
using  System.IO;

// 默认密钥向量
private   static   byte [] Keys  =  {  0x12 ,  0x34 ,  0x56 ,  0x78 ,  0x90 ,  0xAB ,  0xCD ,  0xEF  };
///   <summary>
///  DES加密字符串
///   </summary>
///   <param name="encryptString"> 待加密的字符串 </param>
///   <param name="encryptKey"> 加密密钥,要求为8位 </param>
///   <returns> 加密成功返回加密后的字符串，失败返回源串 </returns>
public   static   string  EncryptDES( string  encryptString,  string  encryptKey)
{
     try
    {
         byte [] rgbKey  =  Encoding.UTF8.GetBytes(encryptKey.Substring( 0 ,  8 ));
         byte [] rgbIV  =  Keys;
         byte [] inputByteArray  =  Encoding.UTF8.GetBytes(encryptString);
        DESCryptoServiceProvider dCSP  =   new  DESCryptoServiceProvider();
        MemoryStream mStream  =   new  MemoryStream();
        CryptoStream cStream  =   new  CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
        cStream.Write(inputByteArray,  0 , inputByteArray.Length);
        cStream.FlushFinalBlock();
         return  Convert.ToBase64String(mStream.ToArray());
    }
     catch
    {
         return  encryptString;
    }
}

///   <summary>
///  DES解密字符串
///   </summary>
///   <param name="decryptString"> 待解密的字符串 </param>
///   <param name="decryptKey"> 解密密钥,要求为8位,和加密密钥相同 </param>
///   <returns> 解密成功返回解密后的字符串，失败返源串 </returns>
public   static   string  DecryptDES( string  decryptString,  string  decryptKey)
{
     try
    {
         byte [] rgbKey  =  Encoding.UTF8.GetBytes(decryptKey);
         byte [] rgbIV  =  Keys;
         byte [] inputByteArray  =  Convert.FromBase64String(decryptString);
        DESCryptoServiceProvider DCSP  =   new  DESCryptoServiceProvider();
        MemoryStream mStream  =   new  MemoryStream();
        CryptoStream cStream  =   new  CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
        cStream.Write(inputByteArray,  0 , inputByteArray.Length);
        cStream.FlushFinalBlock();
         return  Encoding.UTF8.GetString(mStream.ToArray());
    }
     catch
    {
         return  decryptString;
    }
}