public class EncryptClass

    {

        /// <summary>

        /// 返回MD5加密字符串

        /// </summary>

        /// <param name="EncString"></param>

        /// <returns></returns>

        public static string GetMd5String(string EncString)

        {

            return FormsAuthentication.HashPasswordForStoringInConfigFile(EncString + "Hello CSH", "md5");

        }

        // using System.Security.Cryptography;

        public static string GetMd5Hash(String input)

        {

            if (input == null)

            {

                return null;

            }

            MD5 md5Hash = MD5.Create();

            // 将输入字符串转换为字节数组并计算哈希数据

            byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

            // 创建一个 Stringbuilder 来收集字节并创建字符串

            StringBuilder sBuilder = new StringBuilder();

            // 循环遍历哈希数据的每一个字节并格式化为十六进制字符串

            for (int i = ; i < data.Length; i++)

            {

                sBuilder.Append(data[i].ToString("x2"));

            }

            // 返回十六进制字符串

            return sBuilder.ToString();

        }

        #region 密钥加密解密

        //方法

        //加密方法

        public static string Encrypt(string pToEncrypt, string sKey)

        {

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            //把字符串放到byte数组中

            //原来使用的UTF8编码，我改成Unicode编码了，不行

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

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

            //建立加密对象的密钥和偏移量

            //原文使用ASCIIEncoding.ASCII方法的GetBytes方法

            //使得输入密码必须输入英文文本

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

            MemoryStream ms = new MemoryStream();

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

            //Write the byte array into the crypto stream

            //(It will end up in the memory stream)

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

            cs.FlushFinalBlock();

            //Get the data back from the memory stream, and into a string

            StringBuilder ret = new StringBuilder();

            foreach (byte b in ms.ToArray())

            {

                //Format as hex

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

            }

            ret.ToString();

            return ret.ToString();

        }

        //解密方法

        public static string Decrypt(string pToDecrypt, string sKey)

        {

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            //Put the input string into the byte array

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

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

            {

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

                inputByteArray[x] = (byte)i;

            }

            //建立加密对象的密钥和偏移量，此值重要，不能修改

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

            MemoryStream ms = new MemoryStream();

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

            //Flush the data through the crypto stream into the memory stream

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

            cs.FlushFinalBlock();

            //Get the decrypted data back from the memory stream

            //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象

            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());

        }

        #endregion

    }