加密/解密

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

/**//// <summary>
/// SecurityService 的摘要说明
/// </summary>

public sealed class SecurityService
{
    private  const string CIV = "kXwL7X2+fgM=";//密钥 
    private  const string CKEY = "FwGQWRRgKCI=";//初始化向量 

    public SecurityService()
    {
    }

    public static string Encrypt(string Value)
    {
        ICryptoTransform ct;
        MemoryStream ms;
        CryptoStream cs;
        byte[] byt;

        SymmetricAlgorithm mCSP = new DESCryptoServiceProvider();
        ct = mCSP.CreateEncryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV));

        byt = Encoding.UTF8.GetBytes(Value);

        ms = new MemoryStream();
        cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
        cs.Write(byt, 0, byt.Length);
        cs.FlushFinalBlock();

        cs.Close();

        return Convert.ToBase64String(ms.ToArray());
    }

    public static string Decrypt(string Value)
    {
        ICryptoTransform ct;
        MemoryStream ms;
        CryptoStream cs;
        byte[] byt;

        SymmetricAlgorithm mCSP = new DESCryptoServiceProvider();
        ct = mCSP.CreateDecryptor(Convert.FromBase64String(CKEY), Convert.FromBase64String(CIV));

        byt = Convert.FromBase64String(Value);

        ms = new MemoryStream();
        cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
        cs.Write(byt, 0, byt.Length);
        cs.FlushFinalBlock();

        cs.Close();

        return Encoding.UTF8.GetString(ms.ToArray());
    }

}