学步园

    在最近的一个.net项目中，用户希望加密保存到数据库中的信息。参考MSDN，写出了下面这个类！现在拿出来和大家分享！

using System;
using System.Text;
using System.Security.Cryptography;

namespace Util
{
 public class EncryptUtil
 {
  private static string defaultKeyStr = "JERRYHAN581321";

  /// <summary>
  /// 构造方法
  /// </summary>
  private EncryptUtil(){}

  /// <summary>
  /// 使用缺省密钥字符串加密
  /// </summary>
  /// <param name="originalStr">明文</param>
  /// <returns>密文</returns>
  public static string Encrypt(string originalStr)
  {
   return Encrypt(originalStr, defaultKeyStr);
  }

  /// <summary>
  /// 使用缺省密钥解密
  /// </summary>
  /// <param name="originalStr">密文</param>
  /// <returns>明文</returns>
  public static string Decrypt(string originalStr)
  {
   return Decrypt(originalStr, defaultKeyStr, Encoding.Default);
  }

  /// <summary>
  /// 使用给定密钥加密
  /// </summary>
  /// <param name="originalStr">原始文字</param>
  /// <param name="keyStr">密钥</param>
  /// <param name="encoding">字符编码方案</param>
  /// <returns>密文</returns>
  public static string Encrypt(string originalStr, string keyStr)
  {
   byte[] buffBytes = Encoding.Default.GetBytes(originalStr);
   byte[] keyBytes = Encoding.Default.GetBytes(keyStr);
   return Convert.ToBase64String(Encrypt(buffBytes,keyBytes));
  }

  /// <summary>
  /// 使用给定密钥解密
  /// </summary>
  /// <param name="originalStr">密文</param>
  /// <param name="keyStr">密钥</param>
  /// <returns>明文</returns>
  public static string Decrypt(string originalStr, string keyStr)
  {
   return Decrypt(originalStr, keyStr, Encoding.Default);
  }

  /// <summary>
  /// 使用给定密钥解密
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="keyStr">密钥</param>
  /// <param name="encoding">字符编码方案</param>
  /// <returns>明文</returns>
  private static string Decrypt(string encrypted, string keyStr, Encoding encoding)
  {
   byte[] buffBytes = Convert.FromBase64String(encrypted);
   byte[] keyBytes = Encoding.Default.GetBytes(keyStr);
   return encoding.GetString(Decrypt(buffBytes, keyBytes));
  }

  /// <summary>
  /// 生成MD摘要
  /// </summary>
  /// <param name="originalStr">数据源</param>
  /// <returns>摘要</returns>
  public static byte[] MakeMD(byte[] originalStr)
  {
   MD5CryptoServiceProvider hashmd = new MD5CryptoServiceProvider();
   byte[] keyhash = hashmd.ComputeHash(originalStr);
   hashmd = null;
   return keyhash;
  }

  /// <summary>
  /// 使用给定密钥加密
  /// </summary>
  /// <param name="originalStr">明文</param>
  /// <param name="keyStr">密钥</param>
  /// <returns>密文</returns>
  public static byte[] Encrypt(byte[] originalStr, byte[] keyStr)
  {
   TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
   des.Key = MakeMD(keyStr);
   des.Mode = CipherMode.ECB;

   return des.CreateEncryptor().TransformFinalBlock(originalStr, 0, originalStr.Length);
  }

  /// <summary>
  /// 使用给定密钥解密数据
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="keyStr">密钥</param>
  /// <returns>明文</returns>
  public static byte[] Decrypt(byte[] encrypted, byte[] keyStr)
  {
   TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();
   des.Key = MakeMD(keyStr);
   des.Mode = CipherMode.ECB;

   return des.CreateDecryptor().TransformFinalBlock(encrypted, 0, encrypted.Length);
  }

  /// <summary>
  /// 使用给定密钥加密
  /// </summary>
  /// <param name="originalStr">原始数据</param>
  /// <param name="keyStr">密钥</param>
  /// <returns>密文</returns>
  public static byte[] Encrypt(byte[] originalStr)
  {
   byte[] keyStr = Encoding.Default.GetBytes(defaultKeyStr);
   return Encrypt(originalStr,keyStr);
  }

  /// <summary>
  /// 使用缺省密钥解密数据
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="keyStr">密钥</param>
  /// <returns>明文</returns>
  public static byte[] Decrypt(byte[] encrypted)
  {
   byte[] keyStr = Encoding.Default.GetBytes(defaultKeyStr);
   return Decrypt(encrypted,keyStr);
  }
 }
}