EncryptedXml.AddKeyNameMapping(String, Object) Method

Definition

Namespace:

System.Security.Cryptography.Xml

Assembly:

System.Security.Cryptography.Xml.dll

Defines a mapping between a key name and a symmetric key or an asymmetric key.

public:
 void AddKeyNameMapping(System::String ^ keyName, System::Object ^ keyObject);

public void AddKeyNameMapping (string keyName, object keyObject);

member this.AddKeyNameMapping : string * obj -> unit

Public Sub AddKeyNameMapping (keyName As String, keyObject As Object)

Parameters

keyName

String

The name to map to keyObject.

keyObject

Object

The symmetric key to map to keyName.

Exceptions

ArgumentNullException

The value of the keyName parameter is null.

-or-

The value of the keyObject parameter is null.

CryptographicException

The value of the keyObject parameter is not an RSA algorithm or a symmetric key.

Examples

The following code example demonstrates how to encrypt an XML document using a symmetric key. This example embeds a key name in the encrypted XML document that the decrypting method uses to find the appropriate decryption key.

#using <System.Security.dll>
#using <System.dll>
#using <System.Xml.dll>

using namespace System;
using namespace System::Xml;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::Xml;
static void Encrypt( XmlDocument^ Doc, String^ ElementToEncrypt, SymmetricAlgorithm^ Alg, String^ KeyName )
{
   
   // Check the arguments.  
   if ( Doc == nullptr )
      throw gcnew ArgumentNullException( L"Doc" );

   if ( ElementToEncrypt == nullptr )
      throw gcnew ArgumentNullException( L"ElementToEncrypt" );

   if ( Alg == nullptr )
      throw gcnew ArgumentNullException( L"Alg" );

   
   ////////////////////////////////////////////////
   // Find the specified element in the XmlDocument
   // object and create a new XmlElemnt object.
   ////////////////////////////////////////////////
   XmlElement^ elementToEncrypt = dynamic_cast<XmlElement^>(Doc->GetElementsByTagName( ElementToEncrypt )->Item( 0 ));
   
   // Throw an XmlException if the element was not found.
   if ( elementToEncrypt == nullptr )
   {
      throw gcnew XmlException( L"The specified element was not found" );
   }

   
   //////////////////////////////////////////////////
   // Create a new instance of the EncryptedXml class 
   // and use it to encrypt the XmlElement with the 
   // symmetric key.
   //////////////////////////////////////////////////
   EncryptedXml^ eXml = gcnew EncryptedXml;
   
   // Add the key mapping.
   eXml->AddKeyNameMapping( KeyName, Alg );
   
   // Encrypt the element.
   EncryptedData^ edElement = eXml->Encrypt( elementToEncrypt, KeyName );
   
   ////////////////////////////////////////////////////
   // Replace the element from the original XmlDocument
   // object with the EncryptedData element.
   ////////////////////////////////////////////////////
   EncryptedXml::ReplaceElement( elementToEncrypt, edElement, false );
}

static void Decrypt( XmlDocument^ Doc, SymmetricAlgorithm^ Alg, String^ KeyName )
{
   
   // Check the arguments.  
   if ( Doc == nullptr )
      throw gcnew ArgumentNullException( L"Doc" );

   if ( Alg == nullptr )
      throw gcnew ArgumentNullException( L"Alg" );

   if ( KeyName == nullptr )
      throw gcnew ArgumentNullException( L"KeyName" );

   
   // Create a new EncryptedXml object.
   EncryptedXml^ exml = gcnew EncryptedXml( Doc );
   
   // Add the key name mapping.
   exml->AddKeyNameMapping( KeyName, Alg );
   
   // Decrypt the XML document.
   exml->DecryptDocument();
}

int main()
{
   
   // Create an XmlDocument object.
   XmlDocument^ xmlDoc = gcnew XmlDocument;
   
   // Load an XML file into the XmlDocument object.
   try
   {
      xmlDoc->PreserveWhitespace = true;
      xmlDoc->Load( L"test.xml" );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( e->Message );
   }

   
   // Create a new TripleDES key. 
   TripleDESCryptoServiceProvider^ tDESkey = gcnew TripleDESCryptoServiceProvider;
   try
   {
      
      // Encrypt the "creditcard" element.
      Encrypt( xmlDoc, L"creditcard", tDESkey, L"tDesKey" );
      
      // Display the encrypted XML to the console.
      Console::WriteLine( L"Encrypted XML:" );
      Console::WriteLine();
      Console::WriteLine( xmlDoc->OuterXml );
      
      // Decrypt the "creditcard" element.
      Decrypt( xmlDoc, tDESkey, L"tDesKey" );
      
      // Display the encrypted XML to the console.
      Console::WriteLine();
      Console::WriteLine( L"Decrypted XML:" );
      Console::WriteLine();
      Console::WriteLine( xmlDoc->OuterXml );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( e->Message );
   }
   finally
   {
      
      // Clear the TripleDES key.
      tDESkey->Clear();
   }

}

using System;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;

class Program
{
    static void Main(string[] args)
    {

        // Create an XmlDocument object.
        XmlDocument xmlDoc = new XmlDocument();

        // Load an XML file into the XmlDocument object.
        try
        {
            xmlDoc.PreserveWhitespace = true;
            xmlDoc.Load("test.xml");
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

        // Create a new TripleDES key.
        TripleDESCryptoServiceProvider tDESkey = new TripleDESCryptoServiceProvider();

        try
        {
            // Encrypt the "creditcard" element.
            Encrypt(xmlDoc, "creditcard", tDESkey, "tDesKey");

            // Display the encrypted XML to the console.
            Console.WriteLine("Encrypted XML:");
            Console.WriteLine();
            Console.WriteLine(xmlDoc.OuterXml);

            // Decrypt the "creditcard" element.
            Decrypt(xmlDoc, tDESkey, "tDesKey");

            // Display the encrypted XML to the console.
            Console.WriteLine();
            Console.WriteLine("Decrypted XML:");
            Console.WriteLine();
            Console.WriteLine(xmlDoc.OuterXml);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            // Clear the TripleDES key.
            tDESkey.Clear();
        }
    }

    public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, SymmetricAlgorithm Alg, string KeyName)
    {
        // Check the arguments.
        if (Doc == null)
            throw new ArgumentNullException("Doc");
        if (ElementToEncrypt == null)
            throw new ArgumentNullException("ElementToEncrypt");
        if (Alg == null)
            throw new ArgumentNullException("Alg");

        ////////////////////////////////////////////////
        // Find the specified element in the XmlDocument
        // object and create a new XmlElemnt object.
        ////////////////////////////////////////////////

        XmlElement elementToEncrypt = Doc.GetElementsByTagName(ElementToEncrypt)[0] as XmlElement;

        // Throw an XmlException if the element was not found.
        if (elementToEncrypt == null)
        {
            throw new XmlException("The specified element was not found");
        }

        //////////////////////////////////////////////////
        // Create a new instance of the EncryptedXml class
        // and use it to encrypt the XmlElement with the
        // symmetric key.
        //////////////////////////////////////////////////

        EncryptedXml eXml = new EncryptedXml();

        // Add the key mapping.
        eXml.AddKeyNameMapping(KeyName, Alg);

        // Encrypt the element.
        EncryptedData edElement = eXml.Encrypt(elementToEncrypt, KeyName);

        ////////////////////////////////////////////////////
        // Replace the element from the original XmlDocument
        // object with the EncryptedData element.
        ////////////////////////////////////////////////////

        EncryptedXml.ReplaceElement(elementToEncrypt, edElement, false);
    }

    public static void Decrypt(XmlDocument Doc, SymmetricAlgorithm Alg, string KeyName)
    {
        // Check the arguments.
        if (Doc == null)
            throw new ArgumentNullException("Doc");
        if (Alg == null)
            throw new ArgumentNullException("Alg");
        if (KeyName == null)
            throw new ArgumentNullException("KeyName");

        // Create a new EncryptedXml object.
        EncryptedXml exml = new EncryptedXml(Doc);

        // Add the key name mapping.
        exml.AddKeyNameMapping(KeyName, Alg);

        // Decrypt the XML document.
        exml.DecryptDocument();
    }
}

Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml



Module Program

    Sub Main(ByVal args() As String)

        ' Create an XmlDocument object.
        Dim xmlDoc As New XmlDocument()

        ' Load an XML file into the XmlDocument object.
        Try
            xmlDoc.PreserveWhitespace = True
            xmlDoc.Load("test.xml")
        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try

        ' Create a new TripleDES key. 
        Dim tDESkey As New TripleDESCryptoServiceProvider()


        Try
            ' Encrypt the "creditcard" element.
            Encrypt(xmlDoc, "creditcard", tDESkey, "tDesKey")

            ' Display the encrypted XML to the console.
            Console.WriteLine("Encrypted XML:")
            Console.WriteLine()
            Console.WriteLine(xmlDoc.OuterXml)

            ' Decrypt the "creditcard" element.
            Decrypt(xmlDoc, tDESkey, "tDesKey")

            ' Display the encrypted XML to the console.
            Console.WriteLine()
            Console.WriteLine("Decrypted XML:")
            Console.WriteLine()
            Console.WriteLine(xmlDoc.OuterXml)
        Catch e As Exception
            Console.WriteLine(e.Message)
        Finally
            ' Clear the TripleDES key.
            tDESkey.Clear()
        End Try

    End Sub


    Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncrypt As String, ByVal Alg As SymmetricAlgorithm, ByVal KeyName As String)
        ' Check the arguments.  
        If Doc Is Nothing Then
            Throw New ArgumentNullException("Doc")
        End If
        If ElementToEncrypt Is Nothing Then
            Throw New ArgumentNullException("ElementToEncrypt")
        End If
        If Alg Is Nothing Then
            Throw New ArgumentNullException("Alg")
        End If
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Find the specified element in the XmlDocument
        ' object and create a new XmlElemnt object.
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        Dim elementEncrypt As XmlElement = Doc.GetElementsByTagName(ElementToEncrypt)(0) 


        ' Throw an XmlException if the element was not found.
        If ElementToEncrypt Is Nothing Then
            Throw New XmlException("The specified element was not found")
        End If

        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Create a new instance of the EncryptedXml class 
        ' and use it to encrypt the XmlElement with the 
        ' symmetric key.
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        Dim eXml As New EncryptedXml()

        ' Add the key mapping.
        eXml.AddKeyNameMapping(KeyName, Alg)

        ' Encrypt the element.
        Dim edElement As EncryptedData = eXml.Encrypt(elementEncrypt, KeyName)


        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Replace the element from the original XmlDocument
        ' object with the EncryptedData element.
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        EncryptedXml.ReplaceElement(elementEncrypt, edElement, False)

    End Sub


    Sub Decrypt(ByVal Doc As XmlDocument, ByVal Alg As SymmetricAlgorithm, ByVal KeyName As String)
        ' Check the arguments.  
        If Doc Is Nothing Then
            Throw New ArgumentNullException("Doc")
        End If
        If Alg Is Nothing Then
            Throw New ArgumentNullException("Alg")
        End If
        If KeyName Is Nothing Then
            Throw New ArgumentNullException("KeyName")
        End If
        ' Create a new EncryptedXml object.
        Dim exml As New EncryptedXml(Doc)

        ' Add the key name mapping.
        exml.AddKeyNameMapping(KeyName, Alg)

        ' Decrypt the XML document.
        exml.DecryptDocument()

    End Sub
End Module

Remarks

The AddKeyNameMapping method allows you to map a symmetric key or an asymmetric key to a string name. This method adds the values of the keyName and keyObject parameters to a table of valid key name mappings.

Use the ClearKeyNameMappings method to clear the key name mappings table.