C#-一个简单实用的字符串加密解密类

/***************************************************************************
 * * 文件名：PageBase.cs
 * * 创建人：孙振芳
 * * 日  期：2004-07-27
 * * 描  述：本类完成对字符串的加密和解密操作。
 * *
 * * 修改人：
 * * 日  期：
 * * 描  述：
 * *
 * * 版  本：1.0.0
 *************************************************************************** */
using System;
using System.Security.Cryptography;
using System.IO;
using System.Text;

namespace SDSPNDSC.Common
{
    /// <summary>
    /// 通过DES对称加密算法,完成对字符串的加密和解密操作。
    /// </summary>
    public class Encrypt
    {
        private SymmetricAlgorithm mCSP;
        private const string CIV = "kXwL7X2+fgM=";//密钥
        private const string CKEY = "FwGQWRRgKCI=";//初始化向量

        public Encrypt()
        {
            mCSP = new DESCryptoServiceProvider();
        }

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

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

            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());
        }

    }
}