asp.net DES加密解密

数据加密标准DES加密算法是一种对称加密算法，DES 使用一个 56 位的密钥以及附加的 8 位奇偶校验位，产生最大 64 位的分组大小。这是一个迭代的分组密码，使用称为 Feistel 的技术，其中将加密的文本块分成两半。使用子密钥对其中一半应用循环功能，然后将输出与另一半进行“异或”运算；接着交换这两半，这一过程会继续下去，但最后一个循环不交换。DES 使用 16 个循环，使用异或，置换，代换，移位操作四种基本运算。

特点：数据加密标准，速度较快，适用于加密大量数据的场合；

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

namespace DBI.SaaS.Web.Common
{
    public class SecurityHelper
    {
        //默认密钥向量
        private static byte[] Keys = { 0x13, 0x24, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
        /**//// <summary>
            /// DES加密字符串
            /// </summary>
            /// <param name="encryptString">待加密的字符串</param>
            /// <param name="encryptKey">加密密钥,要求为8位</param>
            /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
        public static string EncryptDES(string encryptString, string encryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /**//// <summary>
            /// DES解密字符串
            /// </summary>
            /// <param name="decryptString">待解密的字符串</param>
            /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
            /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
        public static string DecryptDES(string decryptString, string decryptKey)
        {
            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }

        /// <summary>
        /// 创建加密签名
        /// </summary>
        /// <param name="userinfo"></param>
        /// <returns></returns>
        public static string CreateSignature(string userinfo)
        {
            var token = Guid.NewGuid().ToString("N").Substring(0,8);
            return  EncryptDES(userinfo, token);
        }

        /// <summary>
        /// 获取当前随机码
        /// </summary>
        /// <returns></returns>
        public static string GetCode()
        {
            Random rd = new Random();
            int shu = rd.Next(97, 122);
            char c = (char)shu;
            Random rdnumber = new Random();
            var val= rdnumber.Next(0, 99999);
            return c + val.ToString().PadLeft(5, '0');
        }
    }
}