using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace Common.IO.Security
{
    public class DES
    {
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Text">要加密的字符串</param>
        /// <returns></returns>
        public static string Encrypt(string Text)
        {
            return Encrypt(Text, "wHang18189");
        }

        /// <summary>
        /// 加密数据
        /// </summary>
        /// <param name="Text">要加密的字符串</param>
        /// <param name="sKey">加密及解密的密钥</param>
        /// <returns></returns>
        private static string Encrypt(string Text, string sKey)
        {
            using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
            using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
            {
                byte[] inputByteArray;
                inputByteArray = Encoding.Default.GetBytes(Text);
                des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(inputByteArray, 0, inputByteArray.Length);
                    cs.FlushFinalBlock();
                    StringBuilder ret = new StringBuilder();
                    foreach (byte b in ms.ToArray())
                    {
                        ret.AppendFormat("{0:X2}", b);
                    }
                    return ret.ToString();
                }
            }
          
        }

        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Text">要解密的字符串</param>
        /// <returns></returns>
        public static string Decrypt(string Text)
        {
            return Decrypt(Text, "wHang18189");
        }

        /// <summary>
        /// 解密数据
        /// </summary>
        /// <param name="Text">要解密的字符串</param>
        /// <param name="sKey">加密及解密的密钥</param>
        /// <returns></returns>
        private static string Decrypt(string Text, string sKey)
        {
            using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
            using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
            {
                int len;
                len = Text.Length / 2;
                byte[] inputByteArray = new byte[len];
                int x, i;
                for (x = 0; x < len; x++)
                {
                    i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
                    inputByteArray[x] = (byte)i;
                }
                des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));

                using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(inputByteArray, 0, inputByteArray.Length);
                    cs.FlushFinalBlock();
                    return Encoding.Default.GetString(ms.ToArray());
                }
            }
            
        } 
    }
}