MD5加密

    MD5是不可逆的，所以加密之后就无法解密，取用户名和密码时候，需要再加密一边用户输入的数据与数据库中已加密的数据进行比对。如果比对结果一致，则可以判定登陆成功！

   

/*----------------------------------------------------------------
 * 作    者 ：姜  彦 
 * 项目名称 ：Utility.Tool.Common.Helpers
 * 类 名 称 ：SecurityAuthenticateHelper 
 * 命名空间 ：Utility.Tool.Common.Helpers
 * CLR 版本 ：4.0.30319.42000
 * 创建时间 ：2018/10/30 19:46:10
 * 当前版本 ：1.0.0.1 
 * My Email ：jiangyan2008.521@gmail.com 
 *            jiangyan2008.521@qq.com   
 * 描述说明： 
 * 
 * 修改历史： 
 * 
*******************************************************************
 * Copyright @ JiangYan 2018. All rights reserved.
*******************************************************************
------------------------------------------------------------------*/

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

namespace Utility.Tool.Common.Helpers
{
    /// <summary>
    /// 安全认证帮助类
    /// </summary>
    public class SecurityAuthenticateHelper
    {
        public const string KeyDictList = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        private const string KEY_64 = "~!@#$%^&";
        private const string IV_64 = "*()-=+\\|";

        public static string EncodeWithMD5(string str)
        {
            string pwd = "";
            MD5 md5 = MD5.Create();
            Byte[] byt = md5.ComputeHash(Encoding.Unicode.GetBytes(str));
            for (int i = 0; i < byt.Length; i++)
            {
                pwd += byt[i].ToString("x");
            }
            return pwd;
        }

        public static string EncodeWithSHA1(string data)
        {
            byte[] byKey = ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = ASCIIEncoding.ASCII.GetBytes(IV_64);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);
            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
        }

        public static string DecodeWithSHA1(string data)
        {
            byte[] byKey = ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = ASCIIEncoding.ASCII.GetBytes(IV_64);

            byte[] byEnc;
            try
            {
                byEnc = Convert.FromBase64String(data);
            }
            catch
            {
                return null;
            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream(byEnc);
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
            StreamReader sr = new StreamReader(cst);
            return sr.ReadToEnd();
        }

        /*一下几个MD5加密方法新增与201810301958
         * https://www.cnblogs.com/healer007/p/5062189.html
         */

        /// <summary>
        /// 16位MD5加密
        /// </summary>
        /// <param name="password"></param>
        /// <returns></returns>
        public static string MD5Encrypt16(string password)
        {
            var md5 = new MD5CryptoServiceProvider();
            string t2 = BitConverter.ToString(md5.ComputeHash(Encoding.Default.GetBytes(password)), 4, 8);
            t2 = t2.Replace("-", "");
            return t2;
        }

        /// <summary>
        /// 32位MD5加密
        /// </summary>
        /// <param name="password"></param>
        /// <returns></returns>
        public static string MD5Encrypt32(string password)
        {
            string cl = password;
            string pwd = "";
            MD5 md5 = MD5.Create(); //实例化一个md5对像
                                    // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　
            byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl));
            // 通过使用循环，将字节类型的数组转换为字符串，此字符串是常规字符格式化所得
            for (int i = 0; i < s.Length; i++)
            {
                // 将得到的字符串使用十六进制类型格式。格式后的字符是小写的字母，如果使用大写（X）则格式后的字符是大写字符 
                pwd = pwd + s[i].ToString("X");
            }
            return pwd;
        }

        /// <summary>
        /// 64位MD5加密
        /// </summary>
        /// <param name="password"></param>
        /// <returns></returns>
        public static string MD5Encrypt64(string password)
        {
            string cl = password;
            //string pwd = "";
            MD5 md5 = MD5.Create(); //实例化一个md5对像
                                    // 加密后是一个字节类型的数组，这里要注意编码UTF8/Unicode等的选择　
            byte[] s = md5.ComputeHash(Encoding.UTF8.GetBytes(cl));
            return Convert.ToBase64String(s);
        }
      
    }
}