简单的加密与解密代码

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

namespace FaibClass.Encrypting
{

    public class BaseEncrypt
    {
        /**///// <summary> 
        /// 加密
        /// </summary> 
        /// <param name="s">需加密的字串</param> 
        /// <param name="k">密钥</param> 
        /// <returns></returns> 
        public static string EncryptString(string s,string k)
        {
            byte[] byKey=null;
            byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF};
            try
            {
                if(k.Length>8)
                    byKey = System.Text.Encoding.UTF8.GetBytes(k.Substring(0,8));
                else
                    byKey = System.Text.Encoding.UTF8.GetBytes((k+(new string('V',8-k.Length))));
                
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                byte[] inputByteArray = Encoding.UTF8.GetBytes(s);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write) ;
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                return Convert.ToBase64String(ms.ToArray());
            }
            catch(System.Exception error)
            {
                throw new Exception(error.Message);
            }
        }

        /**///// <summary> 
        /// 解密
        /// </summary> 
        /// <param name="s">需解密的字串</param> 
        /// <param name="k">密钥</param> 
        /// <returns></returns> 
        public static string DecryptString(string s,string k)
        {
            byte[] byKey = null;
            byte[] IV= {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; 
            byte[] inputByteArray = new Byte[s.Length];
            try
            {
                if(k.Length>8)
                    byKey = System.Text.Encoding.UTF8.GetBytes(k.Substring(0,8));
                else
                    byKey = System.Text.Encoding.UTF8.GetBytes((k+(new string('V',8-k.Length))));

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                inputByteArray = Convert.FromBase64String(s);
                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)
            {
                throw new Exception(error.Message);
            }
        }
    }
}