稳扎稳打Silverlight(22) - 2.0通信之调用WCF服务, 对传输信息做加密

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Net; 
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Documents; 
using System.Windows.Input; 
using System.Windows.Media; 
using System.Windows.Media.Animation; 
using System.Windows.Shapes; 
 
using Silverlight20.WCFServiceReference; 
using System.Text; 
using System.Security.Cryptography; 
using System.IO; 
 
namespace Silverlight20.Communication 
{ 
         public partial  class Cryptography : UserControl 
        { 
                 public Cryptography() 
                { 
                        InitializeComponent(); 
 
                        Demo(); 
                } 
 
                 void Demo() 
                { 
                        WCFServiceClient client =  new WCFServiceClient(); 
 
                        client.GetUserByCryptographyCompleted+= new EventHandler<GetUserByCryptographyCompletedEventArgs>(client_GetUserByCryptographyCompleted); 
                        client.GetUserByCryptographyAsync(Encrypt( "webabcd")); 
                } 
 
                 void client_GetUserByCryptographyCompleted( object sender, GetUserByCryptographyCompletedEventArgs e) 
                { 
                         if (e.Error !=  null) 
                        { 
                                lblMsg.Text += e.Error.ToString() +  "\r\n"; 
                                 return; 
                        } 
 
                         if (e.Cancelled !=  true) 
                        { 
                                lblMsg.Text +=  string.Format( "姓名：{0}；生日：{1}\r\n", 
                                        e.Result.Name, 
                                        e.Result.DayOfBirth.ToString( "yyyy-MM-dd")); 
                        } 
                } 
 
                 /// <summary> 
                 /// 加密数据 
                 /// </summary> 
                 /// <param name="input">加密前的字符串</param> 
                 /// <returns>加密后的字符串</returns> 
                 private  string Encrypt( string input) 
                { 
                         // 盐值 
                         string saltValue =  "saltValue"; 
                         // 密码值 
                         string pwdValue =  "pwdValue"; 
 
                         byte[] data = UTF8Encoding.UTF8.GetBytes(input); 
                         byte[] salt = UTF8Encoding.UTF8.GetBytes(saltValue); 
 
                         // AesManaged - 高级加密标准(AES) 对称算法的管理类 
                        AesManaged aes =  new 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 
                        Rfc2898DeriveBytes rfc =  new 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 
                        ICryptoTransform encryptTransform = aes.CreateEncryptor(); 
 
                         // 加密后的输出流 
                        MemoryStream encryptStream =  new MemoryStream(); 
 
                         // 将加密后的目标流（encryptStream）与加密转换（encryptTransform）相连接 
                        CryptoStream encryptor =  new CryptoStream(encryptStream, encryptTransform, 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; 
                }                 
        } 
}