练习3：加密数据库连接信息

通过该练习，你将学会如何去加密数据库连接信息。

第一步

打开DataEx3.sln项目，默认的安装路径应该为C:\Program Files\Microsoft Enterprise Library January 2006\labs\cs\Data Access\exercises\ex03\begin，并编译。

第二步 加密数据库连接字符串
1．在Enterprise Library1.1中加密连接字符串，需要依赖于Cryptography Application Block。.NET Framework2.0中已经内置了这项功能，通过Configuration命名空间下的一些类来完成，支持两种类型的加密：

DPAPIProtectedConfigurationProvider：使用Windows Data Protection API (DPAPI)  

RsaProtectedConfigurationProvider：使用RSA算法  

2．选择ProductMaintenance项目，选择Project | Add Reference …菜单命令，在弹出的对话框中选择
 .NET页并添加如下程序集。

System.Configuration.dll

3．在解决方案管理器中选择Program.cs文件，选择View | Code菜单命令，加入如下命名空间。 

using System.Configuration;

4．在方法ProtectConfiguration中添加如下代码。

static void ProtectConfiguration(){
// TODO: Protect the Connection Strings
string provider = "RsaProtectedConfigurationProvider";
Configuration config = null;
config = ConfigurationManager.OpenExeConfiguration
        (ConfigurationUserLevel.None);
ConfigurationSection section = config.ConnectionStrings;
if ((section.SectionInformation.IsProtected == false) &&
(section.ElementInformation.IsLocked == false)){
// Protect (encrypt) the "connectionStrings" section.
section.SectionInformation.ProtectSection(provider);
// Save the encrypted section.
section.SectionInformation.ForceSave = true;
config.Save(ConfigurationSaveMode.Full);
}
}

第三步 运行应用程序  
选择Debug | Start Without Debugging菜单命令并运行应用程序，注意该示例和练习2中的示例是一样的。
在项目bin\Debug目录中打开ProductMaintenance.exe.config配置文件，注意到连接信息已经变成了密文。

<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="dataConfiguration" 
  type="Microsoft.Practices.EnterpriseLibrary.Data.Configuration.
      DatabaseSettings,
  Microsoft.Practices.EnterpriseLibrary.Data, Version=2.0.0.0, Culture=neutral,
  PublicKeyToken=null" />
</configSections>
<dataConfiguration defaultDatabase="QuickStarts Instance" />
<connectionStrings 
   configProtectionProvider="RsaProtectedConfigurationProvider">
<EncryptedData Type=http://www.w3.org/2001/04/xmlenc#Element
xmlns="http://www.w3.org/2001/04/xmlenc#">
<EncryptionMethod Algorithm="http://www.w3.org/2001/04/
               xmlenc#tripledes-cbc" />
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<EncryptedKey xmlns="http://www.w3.org/2001/04/xmlenc#">
<EncryptionMethod
            Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5" />
<KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
<KeyName>Rsa Key</KeyName>
</KeyInfo>
<CipherData>
<CipherValue>xeuEp2HB0xd87DFM0p5UwO78QjRW6A/pb6kGJpS5Rl0F0jHAEPh8wz4
              Jroc1+/I7nvmsCo6a8wzju4Nyd5ZGF6KRZgx56P9wRgkUFtJPgDROrz1ASR
             SIrOfMjw4+1uedT+pl+IuF1EWgEH9Vb+/8A9xmbYWtMBAcR/f/
            quSC1nQ=</CipherValue>
</CipherData>
</EncryptedKey>
</KeyInfo>
<CipherData>
<CipherValue>DrwCnj8uCmkWOjLc2waTGX2pf8QKRFpegQbFv0zcVAwcCkZRvUVnIj9k
         XCLiIx+Pcbrz6H/fccbWxybAA+V7A4unJvDXegyZR1+dW7UqfDOAagTW67FC6iI3vat
         OpGCw30W+xpwhfgptCoFRNiCMWqxvpv++pywSK5SNfB7UZwpl90Q9dBHmmCIVyi/ZbS
           5JY2FLN68nRd9CHZmZLHv9opBm4DvMVdAXt7oKQ6tk9k4HJZzpUc1V8pWLQn7NQro
          A/4WpUDGGgk1gJ2HTBkP2L6wATzxTfQDgZbW/JIgrdollAQbO3/UEAvAnc0swoL/6
         BhWS5MW/9PxjuQK6GhsnSr4Dg7SEdsFPO2bTsAP/lAUeY5y9M3UxC1Q32IwMt8O4gz
        5ppNgYY7R8yKmvH7/S80/i61qJXvSJEQ/hQjx8V2R9okuBaN4XVgLUysmFWsOwxxHiGF
        yuSOECDWnr1c/5XwM7O85gVTzMELdM+N1jVFQTADXQmckOY1nZllRd3cA9CB1Qruqn/R
          xbGOFHT1F6y/4Cbfk7x1CKsmHx0iI0WNJ5iD3KYEq5kosGwWxrOI8C28BiXfEz
          twCzruSP6JpMbw==</CipherValue>
</CipherData>
</EncryptedData>
</connectionStrings>
</configuration>