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

namespace WindowsFormsApplication1
{
    /// <summary>
    /// 加密解密操作类
    /// </summary>
    public class EDHelper
    {        
        private static SymmetricAlgorithm mCSP = new DESCryptoServiceProvider();
        private static string vectorKey = "T/Zl4XkLe8I=";//"cEbmGVzevBs=";
        private static string ivKey = "5vikZLWsu7g=";//"EHCtpIFk84I=";

        /// <summary>
        /// 对一个字符串进行加密
        /// </summary>
        /// <param name="str">需要加密的字符串</param>
        /// <returns>返回一个后的字符串</returns>
        public static string Encrypt(string str)
        {
            if (string.IsNullOrEmpty(str))
                return "";
            try
            {
                byte[] bytes;
                string strResult = string.Empty;

                ICryptoTransform ct = mCSP.CreateEncryptor(Convert.FromBase64String(vectorKey), Convert.FromBase64String(ivKey));
                bytes = Encoding.UTF8.GetBytes(str);
                using (MemoryStream ms = new MemoryStream())
                {
                    CryptoStream cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
                    cs.Write(bytes, 0, bytes.Length);
                    cs.FlushFinalBlock();
                    cs.Close();
                    strResult = Convert.ToBase64String(ms.ToArray());
                }
                return strResult;
            }
            catch
            {
                return "";
            }
        }
        /// <summary>
        /// 对加密的字符串进行解密
        /// </summary>
        /// <param name="str">需要解密的内容</param>
        /// <returns>解密后的字符串</returns>
        public static string Decrypt(string str)
        {
            if (string.IsNullOrEmpty(str))
                return "";
            try
            {
                byte[] bytes;
                string strResult = string.Empty;

                ICryptoTransform ct = mCSP.CreateDecryptor(Convert.FromBase64String(vectorKey), Convert.FromBase64String(ivKey));
                bytes = Convert.FromBase64String(str);
                using (MemoryStream ms = new MemoryStream())
                {
                    CryptoStream cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
                    cs.Write(bytes, 0, bytes.Length);
                    cs.FlushFinalBlock();
                    cs.Close();
                    strResult = Encoding.UTF8.GetString(ms.ToArray());
                }

                return strResult;
            }
            catch { return ""; }
        }
        /// <summary>
        /// 根据字符串获取MD5哈希值
        /// </summary>
        /// <param name="str">目标字符串</param>
        /// <returns>返回MD5哈希值</returns>
        public static int GetMD5Hash(string str)
        {
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] hash = md5.ComputeHash(System.Text.Encoding.Unicode.GetBytes(str));
            Int32 hashInt = System.BitConverter.ToInt32(hash, 0);

            return hashInt;
        }
    }
}