DES加密解密及MD5加密

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yenange/article/details/81974392

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

namespace Util
{
    public class SecurityHelper
    {
        #region 加密解密

        /// <summary>
        /// true加密，false解密
        /// </summary>
        /// <param name="pwdString"></param>
        /// <param name="c"></param>
        /// <returns></returns>
        public static string Base64(string pwdString, bool c)
        {
            if (c)
                return System.Convert.ToBase64String(System.Text.Encoding.Default.GetBytes(pwdString));
            else
            {
                try
                {
                    return System.Text.Encoding.Default.GetString(System.Convert.FromBase64String(pwdString));
                }
                catch (Exception exp)
                {
                    return exp.Message;
                }
            }
        }


        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="str"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        /// http://tool.chacuo.net/cryptdes
        /// 加密模式ECB，填充PKCS7，密码gdnl0760，偏移量gdnl0760，输出hex，字符集GB2312
        public static string Encode(string str, string key)
        {
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Mode = CipherMode.ECB;
            provider.Padding = PaddingMode.PKCS7; //java的PKCS5Padding 对应C#的des.Padding = PaddingMode.PKCS7;
            provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(str);
            MemoryStream stream = new MemoryStream();
            CryptoStream stream2 = new CryptoStream(stream, provider.CreateEncryptor(), CryptoStreamMode.Write);
            stream2.Write(bytes, 0, bytes.Length);
            stream2.FlushFinalBlock();
            StringBuilder builder = new StringBuilder();
            foreach (byte num in stream.ToArray())
            {
                builder.AppendFormat("{0:X2}", num);
            }
            stream.Close();
            return builder.ToString();
        }

        /// <summary>
        /// Des 解密 GB2312 
        /// </summary>
        /// <param name="str">Desc string</param>
        /// <param name="key">Key ,必须为8位 </param>
        /// <returns></returns>
        public static string Decode(string str, string key)
        {
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Mode = CipherMode.ECB;
            provider.Padding = PaddingMode.PKCS7;
            provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            byte[] buffer = new byte[str.Length / 2];
            for (int i = 0; i < (str.Length / 2); i++)
            {
                int num2 = Convert.ToInt32(str.Substring(i * 2, 2), 0x10);
                buffer[i] = (byte)num2;
            }
            MemoryStream stream = new MemoryStream();
            CryptoStream stream2 = new CryptoStream(stream, provider.CreateDecryptor(), CryptoStreamMode.Write);
            stream2.Write(buffer, 0, buffer.Length);
            stream2.FlushFinalBlock();
            stream.Close();
            return Encoding.GetEncoding("GB2312").GetString(stream.ToArray());
        }

        #endregion

        #region GetMD5
        /// <summary>
        /// 与ASP兼容的MD5加密算法
        /// </summary>
        /// <param name="s"></param>
        /// <param name="_input_charset"></param>
        /// <returns></returns>
        public static string GetMD5(string s, string _input_charset)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s));
            StringBuilder sb = new StringBuilder(32);
            for (int i = 0; i < t.Length; i++)
            {
                sb.Append(t[i].ToString("x").PadLeft(2, '0'));
            }
            return sb.ToString();
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string GetMD5(string s)
        {
            return GetMD5(s, "utf-8").ToUpper();
        }
        #endregion
    }
}