c# DES 加密解密方法

#region 密钥

        private static string key = "abcd1234";                                   //密钥(长度必须8位以上)   

        #endregion

        #region DES加密

        public static string EncryptString(string pToEncrypt)
        {

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = Encoding.UTF8.GetBytes(pToEncrypt);

            des.Key = UTF8Encoding.UTF8.GetBytes(key);

            des.IV = UTF8Encoding.UTF8.GetBytes(key);

            MemoryStream ms = new MemoryStream();

            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, , inputByteArray.Length);

            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

            foreach (byte b in ms.ToArray())
            {

                ret.AppendFormat("{0:X2}", b);

            }

            ret.ToString();

            return ret.ToString();

        }

        #endregion

        #region DES解密

        public static string DecryptString(string pToDecrypt)
        {

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / ];

            for (int x = ; x < pToDecrypt.Length / ; x++)
            {

                int i = (Convert.ToInt32(pToDecrypt.Substring(x * , ), ));

                inputByteArray[x] = (byte)i;

            }

            des.Key = UTF8Encoding.UTF8.GetBytes(key);

            des.IV = UTF8Encoding.UTF8.GetBytes(key);

            MemoryStream ms = new MemoryStream();

            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, , inputByteArray.Length);

            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

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

        }

        #endregion

需要引用的命名空间：
using System.IO;
using System.Text;
using System.Security.Cryptography;