转摘一个可逆加密的类（使用3DES加密）

一、提要

命名空间：System.Security.Cryptography.TripleDES 类

简单说明： 表示三重数据加密标准算法的基类，TripleDES 的所有实现都必须从此基类派生。是从 SymmetricAlgorithm 类里继承出来。TripleDES 使用 DES 算法的三次连续迭代。它可以使用两个或三个 56 位密钥。

       使用目的：比较安全的加密一种方式，密钥和矢量的不同，会生产不同的加密字串。因为是DES算法的三次连续迭代，而且算法可逆，这样对于数据保密性和可恢复性都不错。

二、代码示例

本代码参照了部分MSDN上的代码示例，再根据自己的实际情况，补充了一部分MSDN上没有提到的内容

using System;

using System.Security;

using System.Security.Cryptography;

using System.IO;

using System.Text;

using System.Threading;


namespace TRIP3DES

{

    /// <summary>

    /// Class1 的摘要说明。

    /// </summary>

    public class dllEncrypt

    {

      //密钥

      private const string sKey = "qJzGEh6hESZDVJeCnFPGuxzaiB7NLQM3";

      //矢量，矢量可以为空

      private const string sIV = "qcDY6X+aPLw=";

      //构造一个对称算法

      private SymmetricAlgorithm mCSP = new TripleDESCryptoServiceProvider();


        public dllEncrypt(){}


      #region public string EncryptString(string Value)

      /// <summary>

      /// 加密字符串

      /// </summary>

      /// <param name="Value">输入的字符串</param>

      /// <returns>加密后的字符串</returns>

      public string EncryptString(string Value)

      {

         ICryptoTransform ct;

         MemoryStream ms;

         CryptoStream cs;

         byte[] byt;

         mCSP.Key = Convert.FromBase64String(sKey);

         mCSP.IV = Convert.FromBase64String(sIV);

         //指定加密的运算模式

         mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;

        //获取或设置加密算法的填充模式

         mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

         ct = mCSP.CreateEncryptor(mCSP.Key, mCSP.IV);

         byt = Encoding.UTF8.GetBytes(Value);

         ms = new MemoryStream();

         cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);

         cs.Write(byt, 0, byt.Length);

         cs.FlushFinalBlock();

         cs.Close();

         return Convert.ToBase64String(ms.ToArray());

      }

      #endregion


      #region public string DecryptString(string Value)

      /// <summary>

      /// 解密字符串

      /// </summary>

      /// <param name="Value">加过密的字符串</param>

      /// <returns>解密后的字符串</returns>

      public string DecryptString(string Value)

      {

         ICryptoTransform ct;

         MemoryStream ms;

         CryptoStream cs;

         byte[] byt;

         mCSP.Key = Convert.FromBase64String(sKey);

         mCSP.IV = Convert.FromBase64String(sIV);

         mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;

         mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;

         ct = mCSP.CreateDecryptor(mCSP.Key, mCSP.IV);

         byt = Convert.FromBase64String(Value);

         ms = new MemoryStream();

         cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);

         cs.Write(byt, 0, byt.Length);

         cs.FlushFinalBlock();

         cs.Close();


         return Encoding.UTF8.GetString(ms.ToArray());

      }

      #endregion

    }

}

using System;
using System.Security;
using System.Security.Cryptography;
using System.IO;
using System.Text;
using System.Threading;
namespace TRIP3DES
{
/// <summary>
/// Class1 的摘要说明。
/// </summary>
public class dllEncrypt
{
//密钥
private const string sKey = "qJzGEh6hESZDVJeCnFPGuxzaiB7NLQM3";
//矢量，矢量可以为空
private const string sIV = "qcDY6X+aPLw=";
//构造一个对称算法
private SymmetricAlgorithm mCSP = new TripleDESCryptoServiceProvider();
public dllEncrypt(){}
#region public string EncryptString(string Value)
/// <summary>
/// 加密字符串
/// </summary>
/// <param name="Value">输入的字符串</param>
/// <returns>加密后的字符串</returns>
public string EncryptString(string Value)
{
ICryptoTransform ct;
MemoryStream ms;
CryptoStream cs;
byte[] byt;
mCSP.Key = Convert.FromBase64String(sKey);
mCSP.IV = Convert.FromBase64String(sIV);
//指定加密的运算模式
mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;
//获取或设置加密算法的填充模式
mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
ct = mCSP.CreateEncryptor(mCSP.Key, mCSP.IV);
byt = Encoding.UTF8.GetBytes(Value);
ms = new MemoryStream();
cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
cs.Write(byt, 0, byt.Length);
cs.FlushFinalBlock();
cs.Close();
return Convert.ToBase64String(ms.ToArray());
}
#endregion
#region public string DecryptString(string Value)
/// <summary>
/// 解密字符串
/// </summary>
/// <param name="Value">加过密的字符串</param>
/// <returns>解密后的字符串</returns>
public string DecryptString(string Value)
{
ICryptoTransform ct;
MemoryStream ms;
CryptoStream cs;
byte[] byt;
mCSP.Key = Convert.FromBase64String(sKey);
mCSP.IV = Convert.FromBase64String(sIV);
mCSP.Mode = System.Security.Cryptography.CipherMode.ECB;
mCSP.Padding = System.Security.Cryptography.PaddingMode.PKCS7;
ct = mCSP.CreateDecryptor(mCSP.Key, mCSP.IV);
byt = Convert.FromBase64String(Value);
ms = new MemoryStream();
cs = new CryptoStream(ms, ct, CryptoStreamMode.Write);
cs.Write(byt, 0, byt.Length);
cs.FlushFinalBlock();
cs.Close();
return Encoding.UTF8.GetString(ms.ToArray());
}
#endregion
}
}

三、总结

做成类库对于密钥和矢量的保管比较方便，输入输出全部是string型变量，这样也比较方便，密钥的生成可以用mSCP. GenerateKey（）来生成，矢量的生成也可以用mCSP.GenerateIV()来生成。大家也可以自己灵活的编写符合自己的3DES算法。