利用.net提供的类库实现简单的加解密

该代码大体上参考DESCryptoServiceProvider类的构造函数代码示例，有部分改动.

 1    /// <summary>
 2         /// 加密字符串
 3         /// </summary>
 4         /// <param name="encryptText">需加密的字符串</param>
 5         /// <returns>加密后的字符串</returns>
 6         public static string Encrypt(string encryptText)
 7         {
 8             //创建流
 9             MemoryStream ms = new MemoryStream();
 
             DESCryptoServiceProvider key = new DESCryptoServiceProvider();
 
             //创建CryptoStream流对象关联MemoryStream流
             CryptoStream encStream = new CryptoStream(ms, key.CreateEncryptor(Keys, Encoding.UTF8.GetBytes(EncryptKey)), CryptoStreamMode.Write);
 
             //创建StreamWriter对象将字符串写到流中
             StreamWriter sw = new StreamWriter(encStream);
 
             //将字符串写到流中
             sw.WriteLine(encryptText);
 
             //关闭StreamWriter和CryptoStream流.
             sw.Close();
             encStream.Close();
 
             //从写入的流中获取字节数组
             //byte[] buffer = ms.ToArray();
 
 
             string str = Convert.ToBase64String(ms.ToArray());
 
             //关闭MemoryStream流
             ms.Close();
 
             //返回加密后的字符串
             return str;
         }
 
 
 
         /// <summary>
         /// 将字节数组解密成字符串
         /// </summary>
         /// <param name="decryptBytes">加密后的字符串</param>
         /// <returns>解密后的字符串</returns>
         public static string Decrypt(string decryptString)
         {
 
             byte[] decryptBytes = Convert.FromBase64String(decryptString);
 
             //创建流
             MemoryStream ms = new MemoryStream(decryptBytes);
 
 
             DESCryptoServiceProvider key = new DESCryptoServiceProvider();
 
 
             //创建CryptoStream流对象关联MemoryStream流
             CryptoStream encStream = new CryptoStream(ms, key.CreateDecryptor(Keys, Encoding.UTF8.GetBytes(EncryptKey)), CryptoStreamMode.Read);
 
             //创建读取流对象
             StreamReader sr = new StreamReader(encStream);
 
             //返回读取的字符串
             string val = sr.ReadToEnd();
 
             //关闭相关流
             sr.Close();
             encStream.Close();
             ms.Close();
             return val;
         }