在将类保存到 xml 文件之前加密属性

Question

我正在尝试将一些连接字符串作为加密文本保存到我班级的 XML 中。

这是我的课：

using System.Data.SqlClient;
using TechGuyComputing.CompleteOrganizerWPF.Data;

namespace TechGuyComputing.CompleteOrganizerWPF.MiscClasses
{
  public class AppSetting
  {
    private string _dataSource;
    private string _intitialCatalog;
    private string _userId;
    private string _password;

    public string DataSource
    {
      set => _dataSource = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
      get => Encryption.SimpleDecryptWithPassword(_dataSource, GlobalConstants.EncryptionPassword);
    }

    public string IntitialCatalog
    {
      set => _intitialCatalog = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
      get => Encryption.SimpleDecryptWithPassword(_intitialCatalog, GlobalConstants.EncryptionPassword);
    }

    public string UserId
    {
      set => _userId = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
      get => Encryption.SimpleDecryptWithPassword(_userId, GlobalConstants.EncryptionPassword);
    }

    public string Password
    {
      set => _password = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
      get => Encryption.SimpleDecryptWithPassword(_password, GlobalConstants.EncryptionPassword);
    }

    public bool IntegratedSecurity { set; get; }
    public bool MultipleActiveResultSets { set; get; }
    public bool PersistSecurityInfo { set; get; }
  }

  internal static class AppSettings
  {
    public static AppSetting ApplicationSettings;

    public static SqlConnection ConnectionString { get; private set; }


    static AppSettings()
    {
      if (ApplicationSettings == null)
      {
        ApplicationSettings = XmlReader.GetAppSettingsFromXmlFile();
        SetConnectionString();
      }
    }

    public static void SaveAppSettings()
    {
      if (ApplicationSettings == null)
      {
        ApplicationSettings = new AppSetting();
      }
      XmlReader.WriteAppSettingsToXmlFile(ApplicationSettings);
      SetConnectionString();
    }

    private static void SetConnectionString()
    {
      if (string.IsNullOrEmpty(ApplicationSettings.DataSource) || string.IsNullOrEmpty(ApplicationSettings.IntitialCatalog))
      {
        ConnectionString = new SqlConnection();
        return;
      }

      var builder = new SqlConnectionStringBuilder
      {
        DataSource = ApplicationSettings.DataSource,
        InitialCatalog = ApplicationSettings.IntitialCatalog,
        IntegratedSecurity = ApplicationSettings.IntegratedSecurity,
        MultipleActiveResultSets = ApplicationSettings.MultipleActiveResultSets,
        PersistSecurityInfo = ApplicationSettings.PersistSecurityInfo,
        UserID = ApplicationSettings.UserId,
        Password = ApplicationSettings.Password
      };

      ConnectionString = new SqlConnection(builder.ConnectionString);
    }

  }
}

这就是我保存 XML 文件的方式：

using System.IO;
using System.Xml.Serialization;

namespace TechGuyComputing.CompleteOrganizerWPF.MiscClasses
{
  internal static class XmlReader
  {

    public static void WriteAppSettingsToXmlFile(AppSetting appSetting)
    {
      var xs = new XmlSerializer(typeof(AppSetting));
      var tw = new StreamWriter(GlobalConstants.XmlFile);
      xs.Serialize(tw, appSetting);
    }

    public static AppSetting GetAppSettingsFromXmlFile()
    {
      if (!File.Exists(GlobalConstants.XmlFile))
      {
        return new AppSetting();
      }

      using (var sr = new StreamReader(GlobalConstants.XmlFile))
      {
        XmlSerializer xs = new XmlSerializer(typeof(AppSetting));
        return (AppSetting)xs.Deserialize(sr);
      }
    }


  }
}

我的保存工作正常，但它没有将值保存为加密字符串。

我认为这可以即时处理它，但它什么也没做：

public string DataSource
{
  set => _dataSource = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
  get => Encryption.SimpleDecryptWithPassword(_dataSource, GlobalConstants.EncryptionPassword);
}

我没有收到任何错误消息，只是没有加密数据。

任何建议我如何在保存某些属性之前对其进行加密？

编辑： 如果可以防止它，我宁愿不加密整个文件。我只想加密我选择的属性。

Answer 1

您的问题是 XmlSerializer 仅序列化 public 属性和字段 - 您的 AppSetting 类中的公共属性都是未加密的。来自docs

XML 序列化仅将对象的公共字段和属性值序列化为 XML 流。 ...

XML 序列化不会转换方法、索引器、私有字段或只读属性（只读集合除外）。要序列化对象的所有字段和属性，包括公共的和私有的，请使用DataContractSerializer 而不是 XML 序列化。

因此您的选择是：

1. 为加密成员创建公共属性并使用XmlIgnore 标记明文属性，如下所示：

   [System.ComponentModel.Browsable(false), System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never), System.Diagnostics.DebuggerBrowsable(System.Diagnostics.DebuggerBrowsableState.Never)]
   [XmlElement("DataSource")] // Optionally change the element name to be <DataSource>
   public string EncryptedDataSource { get; set; }
   
   [XmlIgnore]
   public string DataSource
   {
       set => EncryptedDataSource = Encryption.SimpleEncryptWithPassword(value, GlobalConstants.EncryptionPassword);
       get => Encryption.SimpleDecryptWithPassword(EncryptedDataSource, GlobalConstants.EncryptionPassword);
   }
   

   演示小提琴#1 here.

2. 切换到DataContractSerializer。首先修改你的类如下：

   [DataContract]
   public class AppSetting
   {
       [DataMember(Name = "DataSource")]
       private string _dataSource;
       [DataMember(Name = "IntitialCatalog")]
       private string _intitialCatalog;
       [DataMember(Name = "UserId")]
       private string _userId;
       [DataMember(Name = "Password")]
       private string _password;
   
       // Remainder unchanged
   

   然后修改XmlReader如下：

   public static void WriteAppSettingsToXmlFile(AppSetting appSetting)
   {
       var serializer = new DataContractSerializer(typeof(AppSetting));
       using (var stream = new FileStream(GlobalConstants.XmlFile, FileMode.Create))
       {
           serializer.WriteObject(stream, appSetting);
       }
   }
   
   public static AppSetting GetAppSettingsFromXmlFile()
   {
       if (!File.Exists(GlobalConstants.XmlFile))
       {
           return new AppSetting();
       }
       using (var stream = File.OpenRead(GlobalConstants.XmlFile))
       {
           var serializer = new DataContractSerializer(typeof(AppSetting));
           return (AppSetting)serializer.ReadObject(stream);
       }
   }
   

   生成的属性都将被加密。

   演示小提琴#2 here.

注意事项：

• 在WriteAppSettingsToXmlFile() 中，您不处置StreamWriter。这将使文件保持打开状态，并可能在以后导致错误。相反，这样做：

  public static void WriteAppSettingsToXmlFile(AppSetting appSetting)
  {
      var xs = new XmlSerializer(typeof(AppSetting));
      using (var tw = new StreamWriter(GlobalConstants.XmlFile))
      {
          xs.Serialize(tw, appSetting);
      }
  }
  

• 虽然用XmlSerializer 序列化的属性必须是公开的，但您可以通过用[Browsable(false)]、[EditorBrowsable(EditorBrowsableState.Never)] 和[DebuggerBrowsable(DebuggerBrowsableState.Never)] 标记它们来稍微隐藏它们，