using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using System.Security;

using System.Security.Cryptography;



namespace PassWord

{

    /// <summary>

    ///  加密解密算法类

    /// </summary>

    public class DES

    {



        /// <summary>

        /// 加密密码

        /// </summary>

        /// <param name="pToEncrypt"></param>

        /// <returns></returns> 

        public static string Encrypt(string pToEncrypt)

        {

            return Encrypt(pToEncrypt, "4Jkw9N3f");

        }

        /// <summary>

        /// 加密

        /// </summary>

        /// <param name="pToEncrypt"></param>

        /// <param name="sKey"></param>

        /// <returns></returns>

        public static string Encrypt(string pToEncrypt, string sKey)

        {

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();



            //Put the string into a byte array

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



            //Create the crypto objects, with the key, as passed in

            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, 0, 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);

            }

            return ret.ToString();

        }



        /// <summary>

        /// 解密

        /// </summary>

        /// <param name="pToDecrypt"></param>

        /// <returns></returns>

        public static string Decrypt(string pToDecrypt)

        {

            return Decrypt(pToDecrypt, "4Jkw9N3f");

        }



        /// <summary>

        /// 解密

        /// </summary>

        /// <param name="pToDecrypt"></param>

        /// <param name="sKey"></param>

        /// <returns></returns>

        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 / 2];

            for (int x = 0; x < pToDecrypt.Length / 2; x++)

            {

                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));

                inputByteArray[x] = (byte)i;

            }



            //Create the crypto objects

            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, 0, inputByteArray.Length);

            cs.FlushFinalBlock();



            //Get the decrypted data back from the memory stream

            StringBuilder ret = new StringBuilder();

            foreach (byte b in ms.ToArray())

            {

                ret.Append((char)b);

            }

            return ret.ToString();

        }

    }

}