public static class EncryptAndDecrypt      {          //加密          public static string Encrypt(string input)          {              // 盐值              string saltValue = "saltValue";              // 密码值              string pwdValue = "pwdValue";              byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes(input);              byte[] salt = System.Text.UTF8Encoding.UTF8.GetBytes(saltValue);              // AesManaged - 高级加密标准(AES) 对称算法的管理类              System.Security.Cryptography.AesManaged aes = new System.Security.Cryptography.AesManaged();              // Rfc2898DeriveBytes - 通过使用基于 HMACSHA1 的伪随机数生成器，实现基于密码的密钥派生功能 (PBKDF2 - 一种基于密码的密钥派生函数)              // 通过 密码 和 salt 派生密钥              System.Security.Cryptography.Rfc2898DeriveBytes rfc = new System.Security.Cryptography.Rfc2898DeriveBytes(pwdValue, salt);              /**/              /*           * AesManaged.BlockSize - 加密操作的块大小（单位：bit）           * AesManaged.LegalBlockSizes - 对称算法支持的块大小（单位：bit）           * AesManaged.KeySize - 对称算法的密钥大小（单位：bit）           * AesManaged.LegalKeySizes - 对称算法支持的密钥大小（单位：bit）           * AesManaged.Key - 对称算法的密钥           * AesManaged.IV - 对称算法的密钥大小           * Rfc2898DeriveBytes.GetBytes(int 需要生成的伪随机密钥字节数) - 生成密钥           */              aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;              aes.KeySize = aes.LegalKeySizes[0].MaxSize;              aes.Key = rfc.GetBytes(aes.KeySize / 8);              aes.IV = rfc.GetBytes(aes.BlockSize / 8);              // 用当前的 Key 属性和初始化向量 IV 创建对称加密器对象              System.Security.Cryptography.ICryptoTransform encryptTransform = aes.CreateEncryptor();              // 加密后的输出流              System.IO.MemoryStream encryptStream = new System.IO.MemoryStream();              // 将加密后的目标流（encryptStream）与加密转换（encryptTransform）相连接              System.Security.Cryptography.CryptoStream encryptor = new System.Security.Cryptography.CryptoStream                  (encryptStream, encryptTransform, System.Security.Cryptography.CryptoStreamMode.Write);              // 将一个字节序列写入当前 CryptoStream （完成加密的过程）              encryptor.Write(data, 0, data.Length);              encryptor.Close();              // 将加密后所得到的流转换成字节数组，再用Base64编码将其转换为字符串              string encryptedString = Convert.ToBase64String(encryptStream.ToArray());              return encryptedString;          }            #region silverlight密码解密          /**/          /// <summary>          /// 解密数据          /// </summary>          /// <param name="input">加密后的字符串</param>          /// <returns>加密前的字符串</returns>          public static string Decrypt(string input)          {              // 盐值（与加密时设置的值一致）              string saltValue = "saltValue";              // 密码值（与加密时设置的值一致）              string pwdValue = "pwdValue";              byte[] encryptBytes = Convert.FromBase64String(input);              byte[] salt = Encoding.UTF8.GetBytes(saltValue);              System.Security.Cryptography.AesManaged aes = new System.Security.Cryptography.AesManaged();              System.Security.Cryptography.Rfc2898DeriveBytes rfc = new System.Security.Cryptography.Rfc2898DeriveBytes(pwdValue, salt);              aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;              aes.KeySize = aes.LegalKeySizes[0].MaxSize;              aes.Key = rfc.GetBytes(aes.KeySize / 8);              aes.IV = rfc.GetBytes(aes.BlockSize / 8);              // 用当前的 Key 属性和初始化向量 IV 创建对称解密器对象              System.Security.Cryptography.ICryptoTransform decryptTransform = aes.CreateDecryptor();              // 解密后的输出流              MemoryStream decryptStream = new MemoryStream();              // 将解密后的目标流（decryptStream）与解密转换（decryptTransform）相连接              System.Security.Cryptography.CryptoStream decryptor = new System.Security.Cryptography.CryptoStream(                  decryptStream, decryptTransform, System.Security.Cryptography.CryptoStreamMode.Write);              // 将一个字节序列写入当前 CryptoStream （完成解密的过程）              decryptor.Write(encryptBytes, 0, encryptBytes.Length);              decryptor.Close();              // 将解密后所得到的流转换为字符串              byte[] decryptBytes = decryptStream.ToArray();              string decryptedString = UTF8Encoding.UTF8.GetString(decryptBytes, 0, decryptBytes.Length);              return decryptedString;          }          #endregion      }