1   // 对称加密帮助类 2     public static class CryptoHelper 3     { 4         //详细参考http://www.cnblogs.com/JimmyZhang/archive/2008/10/02/Cryptograph.html 5         private static ICryptoTransform encryptor;     // 加密器对象 6         private static ICryptoTransform decryptor;     // 解密器对象 7  8         private static SymmetricAlgorithm provider = SymmetricAlgorithm.Create("TripleDES"); 9 10         private const int BufferSize = 1024;11 12 13         /// 
14         /// 加密算法15         /// 
16         /// 为24或16位字符17         /// 被加密的字符串18         /// 
     19         public static string Encrypt(string key, string encryptedText)20         {21             provider.IV = new byte[] { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };22             provider.Key = Encoding.UTF8.GetBytes(key);23 24             encryptor = provider.CreateEncryptor();25             // 创建明文流26             byte[] clearBuffer = Encoding.UTF8.GetBytes(encryptedText);27             MemoryStream clearStream = new MemoryStream(clearBuffer);28 29             // 创建空的密文流30             MemoryStream encryptedStream = new MemoryStream();31 32             CryptoStream cryptoStream =33                 new CryptoStream(encryptedStream, encryptor, CryptoStreamMode.Write);34 35             // 将明文流写入到buffer中36             // 将buffer中的数据写入到cryptoStream中37             int bytesRead = 0;38             byte[] buffer = new byte[BufferSize];39             do40             {41                 bytesRead = clearStream.Read(buffer, 0, BufferSize);42                 cryptoStream.Write(buffer, 0, bytesRead);43             } while (bytesRead > 0);44 45             cryptoStream.FlushFinalBlock();46 47             // 获取加密后的文本48             buffer = encryptedStream.ToArray();49             string str = Convert.ToBase64String(buffer);50             return str;51         }52 53         // 解密算法54         /// 
55         /// 
56         /// 为24或16位字符57         /// 被解密的字符串58         /// 
     59         public static string Decrypt(string key, string decryptedText)60         {61             provider.IV = new byte[] { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };62             provider.Key = Encoding.UTF8.GetBytes(key);63 64             decryptor = provider.CreateDecryptor();65             byte[] encryptedBuffer = Convert.FromBase64String(decryptedText);66             Stream encryptedStream = new MemoryStream(encryptedBuffer);67 68             MemoryStream clearStream = new MemoryStream();69             CryptoStream cryptoStream =70                 new CryptoStream(encryptedStream, decryptor, CryptoStreamMode.Read);71 72             int bytesRead = 0;73             byte[] buffer = new byte[BufferSize];74 75             do76             {77                 bytesRead = cryptoStream.Read(buffer, 0, BufferSize);78                 clearStream.Write(buffer, 0, bytesRead);79             } while (bytesRead > 0);80 81             buffer = clearStream.GetBuffer();82             string str =83                 Encoding.UTF8.GetString(buffer, 0, (int)clearStream.Length);84 85             return str;86         }87 88     }