public class DBSecurity

    {

       //sKey sIV这两个自己随意设定，不能外泄

        private const string sKey = "11,22,33,43,34,56,65,78";

        private const string sIV = "12,23,21,34,65,56,85,96";

        # region 加密解密

        //方法

        //加密方法

        public static string Encrypt(string pToEncrypt)

        {

            try

            {

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                //把字符串放到byte数组中

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

                //建立加密对象的密钥和偏移量

                byte[] b_key = new byte[];

                string[] s_keys = new string[];

                s_keys = sKey.Split(',');

                for (int i = ; i <= ; i++)

                {

                    b_key[i] = Convert.ToByte(s_keys[i].ToString());

                }

                des.Key = b_key;

                byte[] b_iv = new byte[];

                string[] s_ivs = new string[];

                s_ivs = sIV.Split(',');

                for (int i = ; i <= ; i++)

                {

                    b_iv[i] = Convert.ToByte(s_ivs[i].ToString());

                }

                des.IV = b_iv;

                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();

            }

            catch

            {

                return "";

            }

        }

        //解密方法

        public static string Decrypt(string pToDecrypt)

        {

            try

            {

                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

                byte[] b_key = new byte[];

                string[] s_keys = new string[];

                s_keys = sKey.Split(',');

                for (int i = ; i <= ; i++)

                {

                    b_key[i] = Convert.ToByte(s_keys[i].ToString());

                }

                des.Key = b_key;

                byte[] b_iv = new byte[];

                string[] s_ivs = new string[];

                s_ivs = sIV.Split(',');

                for (int i = ; i <= ; i++)

                {

                    b_iv[i] = Convert.ToByte(s_ivs[i].ToString());

                }

                des.IV = b_iv;

                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());

            }

            catch (Exception exp)

            {

                string s = exp.Message.ToString();

                return "";

            }

        }

        #endregion

    }