ASP.NET 包括两个内置的受保护配置提供程序：RSA 和 DPAPI DPAPI 提供程序使用特定于计算机的密钥，因此您必须在每台计算机上实际加密配置设置。默认使用的 RSA 提供程序允许您选择创建 RSA 密钥并将其安装在其他计算机上，这样您就可以在这些计算机之间复制相同的配置文件。此外，您还可以安装其他受保护配置提供程序供系统使用。
调 用配置管理 API 可透明地使用加密的节，因为该 API 自动处理加密和解密。若要通过编程方式将配置节设置为加密的，可获取 ConfigurationSection.SectionInformation 属性，然后传入您选择的保护提供程序调用 ProtectSection 方法。若要使用默认提供程序，可以传入 null 或空字符串。UnprotectSection 方法禁用配置节的加密。
下面的示例演示如何以编程方式对配置节进行加密，配置 API 如何自动处理加密的节。
<%@ Import Namespace="System.Configuration" %><%@ Import Namespace="System.Web.Configuration" %><%@ Import Namespace="System.Xml" %> <script runat="server" language="C#"> public void Page_Load(object source, EventArgs e)
{
if (!IsPostBack) {
UpdateUI();
}
} void ProtectButton_OnClick(Object source, EventArgs e) { String path = Request.CurrentExecutionFilePath; path = path.Substring(0, path.LastIndexOf('/')); // Get configuration. Configuration config = WebConfigurationManager.OpenWebConfiguration(path); ConfigurationSection appSettings = config.GetSection("appSettings"); if (appSettings.SectionInformation.IsProtected) { appSettings.SectionInformation.UnprotectSection(); } else { appSettings.SectionInformation.ProtectSection("DataProtectionConfigurationProvider"); } try { config.Save(); UpdateUI(); } catch (Exception ex) { Response.Write("In order to modify configuration settings, the ASP.NET process account (either the local ASPNET or Network Service account, by default) "); Response.Write("must have write permission granted for the Web.config file in the sample directory"); } } void UpdateUI() { String path = Request.CurrentExecutionFilePath; path = path.Substring(0, path.LastIndexOf('/')); // Get configuration. Configuration config = WebConfigurationManager.OpenWebConfiguration(path); // Show XML for app settings. ConfigurationSection appSettings = config.GetSection("appSettings"); // Set protect button appropriately. if (appSettings.SectionInformation.IsProtected) { Encrypted.Text = "Yes"; ProtectButton.Text = "Unprotect"; } else { Encrypted.Text = "No"; ProtectButton.Text = "Protect"; } // Show XML for app settings. AppSettingsXml.Text = " " + Server.HtmlEncode(appSettings.SectionInformation.GetRawXml()); // Load XML directly from config file, to show encrypted XML. String configPath = Server.MapPath("web.config"); XmlDocument doc = new XmlDocument(); doc.PreserveWhitespace = true; doc.Load(configPath); XmlNode appSettingsXml = doc.SelectSingleNode("configuration/appSettings"); AppSettingsEncrypted.Text = " " + Server.HtmlEncode(appSettingsXml.OuterXml); }</script><html> <head> <title>Encrypted Configuration Sections</title> </head> <body> <form id="form1" runat="server"> <div> <h2>Encrypted:<asp:Label runat="server" id="Encrypted" /></h2><asp:Button runat="server" id="ProtectButton" OnClick="ProtectButton_OnClick" /> <h2>Current XML (decrypted):</h2> <pre> <asp:Label runat="server" ID="AppSettingsXml" /> </pre> <h2>Encrypted contents:</h2> <pre> <asp:Label runat="server" ID="AppSettingsEncrypted" /> </pre> </div> </form> </body></html>对应配置文件如下：
<?xml version="1.0" encoding="utf-8"?><configuration> <configProtectedData /> <appSettings> <add key="currencyService" value="http://www.microsoft.com/services/currencyService.asmx" /> <add key="creditCardValidationService" value="http://www.microsoft.com/services/cc.asmx" /> </appSettings></configuration>效果如图：
