我们知道，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

下面来看一下具体的实现方法，假设已经有这样的一个配置文件：

<?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" />
<connectionStrings>
<add name="QuickStarts" connectionString="Database=EntLibQuickStarts;
        Server=RJ-097;Integrated Security=SSPI;"
providerName="System.Data.SqlClient" />
</connectionStrings>
</configuration>

using System.Configuration;

**//// <summary>
/// Author:TerryLee
/// From:http://terrylee.cnblogs.com
/// </summary>
static void EncryptConfiguration()
{   // 使用什么类型的加密
    string provider = "RsaProtectedConfigurationProvider";
Configuration config = null;
config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.
      None);
    // 加密连接字符串
ConfigurationSection section = config.ConnectionStrings;
if ((section.SectionInformation.IsProtected == false) &&
(section.ElementInformation.IsLocked == false)){
section.SectionInformation.ProtectSection(provider)
section.SectionInformation.ForceSave = true;
config.Save(ConfigurationSaveMode.Full);
}
}

[STAThread]
static void Main()
{// Protect the Connection Strings
  EncryptConfiguration();
Application.Run(new MainForm());
}