C#实现基于Base64的加密解密类实例

using System;
using System.Security.Cryptography; 
using System.Text;
namespace DotNet.Utilities
{
 /// <summary>
 /// Encrypt 的摘要说明。
 /// </summary>
 public class DEncrypt
 {
  /// <summary>
  /// 构造方法
  /// </summary>
  public DEncrypt() 
  { 
  } 
  #region 使用 缺省密钥字符串 加密/解密string
  /// <summary>
  /// 使用缺省密钥字符串加密string
  /// </summary>
  /// <param name="original">明文</param>
  /// <returns>密文</returns>
  public static string Encrypt(string original)
  {
   return Encrypt(original,"sharejs.com");
  }
  /// <summary>
  /// 使用缺省密钥字符串解密string
  /// </summary>
  /// <param name="original">密文</param>
  /// <returns>明文</returns>
  public static string Decrypt(string original)
  {
   return Decrypt(original,"sharejs.com",System.Text.Encoding.Default);
  }
  #endregion
  #region 使用 给定密钥字符串 加密/解密string
  /// <summary>
  /// 使用给定密钥字符串加密string
  /// </summary>
  /// <param name="original">原始文字</param>
  /// <param name="key">密钥</param>
  /// <param name="encoding">字符编码方案</param>
  /// <returns>密文</returns>
  public static string Encrypt(string original, string key) 
  { 
   byte[] buff = System.Text.Encoding.Default.GetBytes(original); 
   byte[] kb = System.Text.Encoding.Default.GetBytes(key);
   return Convert.ToBase64String(Encrypt(buff,kb));   
  }
  /// <summary>
  /// 使用给定密钥字符串解密string
  /// </summary>
  /// <param name="original">密文</param>
  /// <param name="key">密钥</param>
  /// <returns>明文</returns>
  public static string Decrypt(string original, string key)
  {
   return Decrypt(original,key,System.Text.Encoding.Default);
  }
  /// <summary>
  /// 使用给定密钥字符串解密string,返回指定编码方式明文
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="key">密钥</param>
  /// <param name="encoding">字符编码方案</param>
  /// <returns>明文</returns>
  public static string Decrypt(string encrypted, string key,Encoding encoding) 
  {    
   byte[] buff = Convert.FromBase64String(encrypted); 
   byte[] kb = System.Text.Encoding.Default.GetBytes(key);
   return encoding.GetString(Decrypt(buff,kb));   
  } 
  #endregion
  #region 使用 缺省密钥字符串 加密/解密/byte[]
  /// <summary>
  /// 使用缺省密钥字符串解密byte[]
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="key">密钥</param>
  /// <returns>明文</returns>
  public static byte[] Decrypt(byte[] encrypted) 
  { 
   byte[] key = System.Text.Encoding.Default.GetBytes("sharejs.com"); 
   return Decrypt(encrypted,key);   
  }
  /// <summary>
  /// 使用缺省密钥字符串加密
  /// </summary>
  /// <param name="original">原始数据</param>
  /// <param name="key">密钥</param>
  /// <returns>密文</returns>
  public static byte[] Encrypt(byte[] original) 
  { 
   byte[] key = System.Text.Encoding.Default.GetBytes("sharejs.com"); 
   return Encrypt(original,key);   
  } 
  #endregion
  #region 使用 给定密钥 加密/解密/byte[]
  /// <summary>
  /// 生成MD5摘要
  /// </summary>
  /// <param name="original">数据源</param>
  /// <returns>摘要</returns>
  public static byte[] MakeMD5(byte[] original)
  {
   MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();  
   byte[] keyhash = hashmd5.ComputeHash(original);    
   hashmd5 = null; 
   return keyhash;
  }
  /// <summary>
  /// 使用给定密钥加密
  /// </summary>
  /// <param name="original">明文</param>
  /// <param name="key">密钥</param>
  /// <returns>密文</returns>
  public static byte[] Encrypt(byte[] original, byte[] key) 
  { 
   TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider();    
   des.Key = MakeMD5(key);
   des.Mode = CipherMode.ECB; 
   return des.CreateEncryptor().TransformFinalBlock(original, 0, original.Length);   
  } 
  /// <summary>
  /// 使用给定密钥解密数据
  /// </summary>
  /// <param name="encrypted">密文</param>
  /// <param name="key">密钥</param>
  /// <returns>明文</returns>
  public static byte[] Decrypt(byte[] encrypted, byte[] key) 
  { 
   TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider(); 
   des.Key = MakeMD5(key);  
   des.Mode = CipherMode.ECB; 
   return des.CreateDecryptor().TransformFinalBlock(encrypted, 0, encrypted.Length);
  } 
  #endregion
 }
}