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(, ));
des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
System.IO.MemoryStream ms = new System.IO.MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, , 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 / ;
byte[] inputByteArray = new byte[len];
int x, i;
for (x = ; x < len; x++)
{
i = Convert.ToInt32(Text.Substring(x * , ), );
inputByteArray[x] = (byte)i;
}
des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
System.IO.MemoryStream ms = new System.IO.MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, , 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 = { , , , , , , , , , , , , , , , , , , , , , , , }; //定义密钥
byte[] IV = { , , , , , , , }; //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, , 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 = { , , , , , , , , , , , , , , , , , , , , , , , }; //定义密钥
byte[] IV = { , , , , , , , }; //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, , 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);
}
}
}
}
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;
}
}
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 / ;
byte[] inputByteArray = new byte[len];
int x, i;
for (x = ; x < len; x++)
{
i = Convert.ToInt32(Text.Substring(x * , ), );
inputByteArray[x] = (byte)i;
}
des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(, ));
System.IO.MemoryStream ms = new System.IO.MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, , inputByteArray.Length);
cs.FlushFinalBlock();
return Encoding.Default.GetString(ms.ToArray());
}
}
下面是解密效果，如果客户不是专业人士，我们公网数据库连接就是安全的了：
