如何用C#实现DES加密解密

代码如下：

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

namespace Common
...{
    /**//// summary
    /// DESEncrypt加密解密算法。
    /// /summary
    public sealed class DESEncrypt
    ...{
        private DESEncrypt()
        ...{
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

        private static string key = "zhoufoxcn";

        /**//// summary
        /// 对称加密解密的密钥
        /// /summary
        public static string Key
        ...{
            get
            ...{
                return key;
            }
            set
            ...{
                key = value;
            }
        }

        /**//// summary
        /// DES加密
        /// /summary
        /// param name="encryptString"/param
        /// returns/returns
        public static string DesEncrypt(string encryptString)
        ...{
            byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
            byte[] keyIV = keyBytes;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, provider.CreateEncryptor(keyBytes, keyIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }

        /**//// summary
        /// DES解密
        /// /summary
        /// param name="decryptString"/param
        /// returns/returns
        public static string DesDecrypt(string decryptString)
        ...{
            byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
            byte[] keyIV = keyBytes;
            byte[] inputByteArray = Convert.FromBase64String(decryptString);
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, provider.CreateDecryptor(keyBytes, keyIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Encoding.UTF8.GetString(mStream.ToArray());
        }
    }
}