connectionString加密

最新推荐文章于 2020-12-14 02:10:38 发布

转载最新推荐文章于 2020-12-14 02:10:38 发布 · 351 阅读

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本文介绍了一种用于保护数据库访问字符串免受非法访问的加密技术，通过使用MD5和TripleDES算法对连接字符串进行加密，并提供了解密方法。加密和解密类的实现确保了敏感信息的安全性，同时在配置文件中存储密钥和密文以增加安全性。通过在应用中使用此加密连接字符串，可以防止未经授权的访问。

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首先是加密，解密类。

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

namespace SqlConnectionEncryp
{
    public class Encrypt
    {
        /// <summary> 
        ///  MD5加密 
        /// </summary> 
        public static string MD5Encrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] 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));
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            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> 
        ///  MD5解密
        /// </summary>  
        public static string MD5Decrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            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));
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return Encoding.Default.GetString(ms.ToArray());
        }


        /// <summary>
        /// TripleDES加密
        /// </summary>
        public static string TripleDESEncrypting(string strSource)
        {
            try
            {
                byte[] bytIn = Encoding.Default.GetBytes(strSource);
                byte[] key = { 42, 16, 93, 156, 78, 4, 218, 32, 15, 167, 44, 80, 26, 20, 155, 112, 2, 94, 11, 204, 119, 35, 184, 197 }; //定义密钥
                byte[] IV = { 55, 103, 246, 79, 36, 99, 167, 3 };  //定义偏移量
                TripleDESCryptoServiceProvider TripleDES = new TripleDESCryptoServiceProvider();
                TripleDES.IV = IV;
                TripleDES.Key = key;
                ICryptoTransform encrypto = TripleDES.CreateEncryptor();
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
                cs.Write(bytIn, 0, bytIn.Length);
                cs.FlushFinalBlock();
                byte[] bytOut = ms.ToArray();
                return System.Convert.ToBase64String(bytOut);
            }
            catch (Exception ex)
            {
                throw new Exception("加密时候出现错误!错误提示:\n" + ex.Message);
            }
        }

        /// <summary>
        /// TripleDES解密
        /// </summary>
        public static string TripleDESDecrypting(string Source)
        {
            try
            {
                byte[] bytIn = System.Convert.FromBase64String(Source);
                byte[] key = { 42, 16, 93, 156, 78, 4, 218, 32, 15, 167, 44, 80, 26, 20, 155, 112, 2, 94, 11, 204, 119, 35, 184, 197 }; //定义密钥
                byte[] IV = { 55, 103, 246, 79, 36, 99, 167, 3 };   //定义偏移量
                TripleDESCryptoServiceProvider TripleDES = new TripleDESCryptoServiceProvider();
                TripleDES.IV = IV;
                TripleDES.Key = key;
                ICryptoTransform encrypto = TripleDES.CreateDecryptor();
                System.IO.MemoryStream ms = new System.IO.MemoryStream(bytIn, 0, bytIn.Length);
                CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
                StreamReader strd = new StreamReader(cs, Encoding.Default);
                return strd.ReadToEnd();
            }
            catch (Exception ex)
            {
                throw new Exception("解密时候出现错误!错误提示:\n" + ex.Message);
            }
        }
    }
}

View Code

加密使用MD5Decrypt，自己给定一个密钥。下面是对连接字符串加密的界面：

代码和测试效果：

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnCreate_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(txtClear.Text))
            {
                MessageBox.Show("明文不能为空！");
            }
            if (string.IsNullOrEmpty(txtKey.Text))
            {
                MessageBox.Show("密钥不能为空！");
            }

            string strCipher = Encrypt.MD5Encrypt(txtClear.Text, txtKey.Text);
            txtCipher.Text = strCipher;
        }
    }

View Code

加密的原因是，为客户开发的某些程序，需要访问公司（我们自己工作的）在公网的数据库，但是我们不能将明文数据库访问字符串，存放在客户的应用程序上，最好的办法就是将其加密。下面就在一个为客户开发的程序中使用这个加密连接。这里，我将密钥和密文都写在了配置文件中。如果用户猜出我的加密算法，他们可以根据密钥，可以轻松获得我的明文。所以，不要傻到直接将密钥配置命名成key。如果将密钥写死在代码中就不方便控制，客户反编译同样能获知加密算法和密钥，从而获得本来的连接字符串。

下面在获取连接字符串时，都要对其进行解密，所以构造一个解密类是必要的。

public class ConfigHelper
    {
        /// <summary>
        /// 获取普通连接
        /// </summary>
        public static string GetConn(string conn)
        {
            return ConfigurationManager.ConnectionStrings[conn].ConnectionString;
        }
        /// <summary>
        /// 获取appsetting
        /// </summary>
        public static string GetAppSetting(string key)
        {
            return ConfigurationManager.AppSettings[key];
        }
        /// <summary>
        /// 获取解密连接
        /// </summary>
        public static string GetConn(string conn, string key)
        {
            string strConn = GetConn(conn);
            string strKey = GetAppSetting(key);
            return MD5Decrypt(strConn, strKey);
        }

        /// <summary> 
        ///  MD5解密
        /// </summary>  
        private static string MD5Decrypt(string Text, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            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));
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return Encoding.Default.GetString(ms.ToArray());
        }
    }