EncryptionMethod クラス

定義

名前空間:

System.Security.Cryptography.Xml

アセンブリ:

System.Security.Cryptography.Xml.dll

XML 暗号化に使用する暗号化アルゴリズムをカプセル化します。

public ref class EncryptionMethod

public class EncryptionMethod

type EncryptionMethod = class

Public Class EncryptionMethod

継承

Object

EncryptionMethod

例

次のコード例では、 アルゴリズムを使用 TripleDES して XML ドキュメントを暗号化する単純なユーティリティ クラスを作成する方法を示します。

#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;

ref class TrippleDESDocumentEncryption
{
protected:
   XmlDocument^ docValue;
   TripleDES^ algValue;

public:
   TrippleDESDocumentEncryption( XmlDocument^ Doc, TripleDES^ Key )
   {
      if ( Doc != nullptr )
      {
         docValue = Doc;
      }
      else
      {
         throw gcnew ArgumentNullException( L"Doc" );
      }

      if ( Key != nullptr )
      {
         algValue = Key;
      }
      else
      {
         throw gcnew ArgumentNullException( L"Key" );
      }
   }


   property XmlDocument^ Doc
   {
      XmlDocument^ get()
      {
         return docValue;
      }

      void set( XmlDocument^ value )
      {
         docValue = value;
      }

   }

   property TripleDES^ Alg
   {
      TripleDES^ get()
      {
         return algValue;
      }

      void set( TripleDES^ value )
      {
         algValue = value;
      }

   }
   void Clear()
   {
      if ( algValue != nullptr )
      {
         algValue->Clear();
      }
      else
      {
         throw gcnew Exception( L"No TripleDES key was found to clear." );
      }
   }

   void Encrypt( String^ Element )
   {

      // Find the element by name and create a new
      // XmlElement object.
      XmlElement^ inputElement = dynamic_cast<XmlElement^>(docValue->GetElementsByTagName( Element )->Item( 0 ));

      // If the element was not found, throw an exception.
      if ( inputElement == nullptr )
      {
         throw gcnew Exception( L"The element was not found." );
      }


      // Create a new EncryptedXml object.
      EncryptedXml^ exml = gcnew EncryptedXml( docValue );

      // Encrypt the element using the symmetric key.
      array<Byte>^rgbOutput = exml->EncryptData( inputElement, algValue, false );

      // Create an EncryptedData object and populate it.
      EncryptedData^ ed = gcnew EncryptedData;

      // Specify the namespace URI for XML encryption elements.
      ed->Type = EncryptedXml::XmlEncElementUrl;

      // Specify the namespace URI for the TrippleDES algorithm.
      ed->EncryptionMethod = gcnew EncryptionMethod( EncryptedXml::XmlEncTripleDESUrl );

      // Create a CipherData element.
      ed->CipherData = gcnew CipherData;

      // Set the CipherData element to the value of the encrypted XML element.
      ed->CipherData->CipherValue = rgbOutput;

      // Replace the plaintext XML elemnt with an EncryptedData element.
      EncryptedXml::ReplaceElement( inputElement, ed, false );
   }

   void Decrypt()
   {

      // XmlElement object.
      XmlElement^ encryptedElement = dynamic_cast<XmlElement^>(docValue->GetElementsByTagName( L"EncryptedData" )->Item( 0 ));

      // If the EncryptedData element was not found, throw an exception.
      if ( encryptedElement == nullptr )
      {
         throw gcnew Exception( L"The EncryptedData element was not found." );
      }


      // Create an EncryptedData object and populate it.
      EncryptedData^ ed = gcnew EncryptedData;
      ed->LoadXml( encryptedElement );

      // Create a new EncryptedXml object.
      EncryptedXml^ exml = gcnew EncryptedXml;

      // Decrypt the element using the symmetric key.
      array<Byte>^rgbOutput = exml->DecryptData( ed, algValue );

      // Replace the encryptedData element with the plaintext XML elemnt.
      exml->ReplaceData( encryptedElement, rgbOutput );
   }

};

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 );
      return 0;
   }


   // Create a new TripleDES key.
   TripleDESCryptoServiceProvider^ tDESkey = gcnew TripleDESCryptoServiceProvider;

   // Create a new instance of the TrippleDESDocumentEncryption object
   // defined in this sample.
   TrippleDESDocumentEncryption^ xmlTDES = gcnew TrippleDESDocumentEncryption( xmlDoc,tDESkey );
   try
   {

      // Encrypt the "creditcard" element.
      xmlTDES->Encrypt( L"creditcard" );

      // Display the encrypted XML to the console.
      Console::WriteLine( L"Encrypted XML:" );
      Console::WriteLine();
      Console::WriteLine( xmlTDES->Doc->OuterXml );

      // Decrypt the "creditcard" element.
      xmlTDES->Decrypt();

      // Display the encrypted XML to the console.
      Console::WriteLine();
      Console::WriteLine( L"Decrypted XML:" );
      Console::WriteLine();
      Console::WriteLine( xmlTDES->Doc->OuterXml );
   }
   catch ( Exception^ e )
   {
      Console::WriteLine( e->Message );
   }
   finally
   {

      // Clear the TripleDES key.
      xmlTDES->Clear();
   }

   return 1;
}

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);
                return;
            }

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

            // Create a new instance of the TrippleDESDocumentEncryption object
            // defined in this sample.
            TrippleDESDocumentEncryption xmlTDES = new TrippleDESDocumentEncryption(xmlDoc, tDESkey);
            
            try
            {
                // Encrypt the "creditcard" element.
                xmlTDES.Encrypt("creditcard");

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

                // Decrypt the "creditcard" element.
                xmlTDES.Decrypt();

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

class TrippleDESDocumentEncryption
{
    protected XmlDocument docValue;
    protected TripleDES algValue;

    public TrippleDESDocumentEncryption(XmlDocument Doc, TripleDES Key)
    {
        if (Doc != null)
        {
            docValue = Doc;
        }
        else
        {
            throw new ArgumentNullException("Doc");
        }

        if (Key != null)
        {

            algValue = Key;
        }
        else
        {
            throw new ArgumentNullException("Key");
        }
    }

    public XmlDocument Doc { set { docValue = value; } get { return docValue; } }
    public TripleDES Alg { set { algValue = value; } get { return algValue; } }

    public void Clear()
    {
        if (algValue != null)
        {
            algValue.Clear();
        }
        else
        {
            throw new Exception("No TripleDES key was found to clear.");
        }
    }

    public void Encrypt(string Element)
    {
        // Find the element by name and create a new
        // XmlElement object.
        XmlElement inputElement = docValue.GetElementsByTagName(Element)[0] as XmlElement;

        // If the element was not found, throw an exception.
        if (inputElement == null)
        {
            throw new Exception("The element was not found.");
        }

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

        // Encrypt the element using the symmetric key.
        byte[] rgbOutput = exml.EncryptData(inputElement, algValue, false);

        // Create an EncryptedData object and populate it.
        EncryptedData ed = new EncryptedData();

        // Specify the namespace URI for XML encryption elements.
        ed.Type = EncryptedXml.XmlEncElementUrl;

        // Specify the namespace URI for the TrippleDES algorithm.
        ed.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncTripleDESUrl);

        // Create a CipherData element.
        ed.CipherData = new CipherData();

        // Set the CipherData element to the value of the encrypted XML element.
        ed.CipherData.CipherValue = rgbOutput;

        // Replace the plaintext XML elemnt with an EncryptedData element.
        EncryptedXml.ReplaceElement(inputElement, ed, false);
    }

    public void Decrypt()
    {

        // XmlElement object.
        XmlElement encryptedElement = docValue.GetElementsByTagName("EncryptedData")[0] as XmlElement;

        // If the EncryptedData element was not found, throw an exception.
        if (encryptedElement == null)
        {
            throw new Exception("The EncryptedData element was not found.");
        }

        // Create an EncryptedData object and populate it.
        EncryptedData ed = new EncryptedData();
        ed.LoadXml(encryptedElement);

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

        // Decrypt the element using the symmetric key.
        byte[] rgbOutput = exml.DecryptData(ed, algValue);

        // Replace the encryptedData element with the plaintext XML elemnt.
        exml.ReplaceData(encryptedElement, rgbOutput);
    }
}

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.
        xmlDoc.PreserveWhitespace = True
        xmlDoc.Load("test.xml")


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

        ' Create a new instance of the TrippleDESDocumentEncryption object
        ' defined in this sample.
        Dim xmlTDES As New TrippleDESDocumentEncryption(xmlDoc, tDESkey)

        Try
            ' Encrypt the "creditcard" element.
            xmlTDES.Encrypt("creditcard")

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

            ' Decrypt the "creditcard" element.
            xmlTDES.Decrypt()

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

    End Sub
End Module 'Program



Class TrippleDESDocumentEncryption
    Protected docValue As XmlDocument
    Protected algValue As TripleDES


    Public Sub New(ByVal Doc As XmlDocument, ByVal Key As TripleDES)
        If Not (Doc Is Nothing) Then
            docValue = Doc
        Else
            Throw New ArgumentNullException("Doc")
        End If

        If Not (Key Is Nothing) Then

            algValue = Key
        Else
            Throw New ArgumentNullException("Key")
        End If

    End Sub


    Public Property Doc() As XmlDocument
        Get
            Return docValue
        End Get
        Set(ByVal value As XmlDocument)
            docValue = value
        End Set
    End Property

    Public Property Alg() As TripleDES
        Get
            Return algValue
        End Get
        Set(ByVal value As TripleDES)
            algValue = value
        End Set
    End Property

    Public Sub Clear()
        If Not (algValue Is Nothing) Then
            algValue.Clear()
        Else
            Throw New Exception("No TripleDES key was found to clear.")
        End If

    End Sub


    Public Sub Encrypt(ByVal Element As String)
        ' Find the element by name and create a new
        ' XmlElement object.
        Dim inputElement As XmlElement = docValue.GetElementsByTagName(Element)(0)

        ' If the element was not found, throw an exception.
        If inputElement Is Nothing Then
            Throw New Exception("The element was not found.")
        End If

        ' Create a new EncryptedXml object.
        Dim exml As New EncryptedXml(docValue)

        ' Encrypt the element using the symmetric key.
        Dim rgbOutput As Byte() = exml.EncryptData(inputElement, algValue, False)

        ' Create an EncryptedData object and populate it.
        Dim ed As New EncryptedData()

        ' Specify the namespace URI for XML encryption elements.
        ed.Type = EncryptedXml.XmlEncElementUrl

        ' Specify the namespace URI for the TrippleDES algorithm.
        ed.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncTripleDESUrl)

        ' Create a CipherData element.
        ed.CipherData = New CipherData()

        ' Set the CipherData element to the value of the encrypted XML element.
        ed.CipherData.CipherValue = rgbOutput

        ' Replace the plaintext XML elemnt with an EncryptedData element.
        EncryptedXml.ReplaceElement(inputElement, ed, False)

    End Sub


    Public Sub Decrypt()

        ' XmlElement object.
        Dim encryptedElement As XmlElement = docValue.GetElementsByTagName("EncryptedData")(0)

        ' If the EncryptedData element was not found, throw an exception.
        If encryptedElement Is Nothing Then
            Throw New Exception("The EncryptedData element was not found.")
        End If

        ' Create an EncryptedData object and populate it.
        Dim ed As New EncryptedData()
        ed.LoadXml(encryptedElement)

        ' Create a new EncryptedXml object.
        Dim exml As New EncryptedXml()

        ' Decrypt the element using the symmetric key.
        Dim rgbOutput As Byte() = exml.DecryptData(ed, algValue)

        ' Replace the encryptedData element with the plaintext XML elemnt.
        exml.ReplaceData(encryptedElement, rgbOutput)

    End Sub
End Class

次のコード例では、対称キーを使用して XML ドキュメントを暗号化する方法を示します。 この例では、暗号化された XML ドキュメントにキー情報は含まれません。

#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 )
{

   // 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;
   array<Byte>^encryptedElement = eXml->EncryptData( elementToEncrypt, Alg, false );

   ////////////////////////////////////////////////
   // Construct an EncryptedData object and populate
   // it with the desired encryption information.
   ////////////////////////////////////////////////
   EncryptedData^ edElement = gcnew EncryptedData;
   edElement->Type = EncryptedXml::XmlEncElementUrl;

   // Create an EncryptionMethod element so that the
   // receiver knows which algorithm to use for decryption.
   // Determine what kind of algorithm is being used and
   // supply the appropriate URL to the EncryptionMethod element.
   String^ encryptionMethod = nullptr;
   if ( dynamic_cast<TripleDES^>(Alg) )
   {
      encryptionMethod = EncryptedXml::XmlEncTripleDESUrl;
   }
   else
   if ( dynamic_cast<DES^>(Alg) )
   {
      encryptionMethod = EncryptedXml::XmlEncDESUrl;
   }
   else
   if ( dynamic_cast<Aes^>(Alg) )
   {
      switch ( Alg->KeySize )
      {
         case 128:
            encryptionMethod = EncryptedXml::XmlEncAES128Url;
            break;

         case 192:
            encryptionMethod = EncryptedXml::XmlEncAES192Url;
            break;

         case 256:
            encryptionMethod = EncryptedXml::XmlEncAES256Url;
            break;
      }
   }
   else
   {

      // Throw an exception if the transform is not in the previous categories
      throw gcnew CryptographicException( L"The specified algorithm is not supported for XML Encryption." );
   }



   edElement->EncryptionMethod = gcnew EncryptionMethod( encryptionMethod );

   // Add the encrypted element data to the
   // EncryptedData object.
   edElement->CipherData->CipherValue = encryptedElement;

   ////////////////////////////////////////////////////
   // Replace the element from the original XmlDocument
   // object with the EncryptedData element.
   ////////////////////////////////////////////////////
   EncryptedXml::ReplaceElement( elementToEncrypt, edElement, false );
}

static void Decrypt( XmlDocument^ Doc, SymmetricAlgorithm^ Alg )
{

   // Check the arguments.
   if ( Doc == nullptr )
      throw gcnew ArgumentNullException( L"Doc" );

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


   // Find the EncryptedData element in the XmlDocument.
   XmlElement^ encryptedElement = dynamic_cast<XmlElement^>(Doc->GetElementsByTagName( L"EncryptedData" )->Item( 0 ));

   // If the EncryptedData element was not found, throw an exception.
   if ( encryptedElement == nullptr )
   {
      throw gcnew XmlException( L"The EncryptedData element was not found." );
   }


   // Create an EncryptedData object and populate it.
   EncryptedData^ edElement = gcnew EncryptedData;
   edElement->LoadXml( encryptedElement );

   // Create a new EncryptedXml object.
   EncryptedXml^ exml = gcnew EncryptedXml;

   // Decrypt the element using the symmetric key.
   array<Byte>^rgbOutput = exml->DecryptData( edElement, Alg );

   // Replace the encryptedData element with the plaintext XML element.
   exml->ReplaceData( encryptedElement, rgbOutput );
}

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 );
      return 0;
   }


   // Create a new TripleDES key.
   TripleDESCryptoServiceProvider^ tDESkey = gcnew TripleDESCryptoServiceProvider;
   try
   {

      // Encrypt the "creditcard" element.
      Encrypt( xmlDoc, L"creditcard", 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 );

      // 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);
            return;
        }

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

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

            // 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)
    {
        // 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();

        byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, Alg, false);

        ////////////////////////////////////////////////
        // Construct an EncryptedData object and populate
        // it with the desired encryption information.
        ////////////////////////////////////////////////

        EncryptedData edElement = new EncryptedData();
        edElement.Type = EncryptedXml.XmlEncElementUrl;

        // Create an EncryptionMethod element so that the
        // receiver knows which algorithm to use for decryption.
        // Determine what kind of algorithm is being used and
        // supply the appropriate URL to the EncryptionMethod element.

        string encryptionMethod = null;

        if (Alg is TripleDES)
        {
            encryptionMethod = EncryptedXml.XmlEncTripleDESUrl;
        }
        else if (Alg is DES)
        {
            encryptionMethod = EncryptedXml.XmlEncDESUrl;
        }
        else if (Alg is Aes)
        {
            switch (Alg.KeySize)
            {
                case 128:
                    encryptionMethod = EncryptedXml.XmlEncAES128Url;
                    break;
                case 192:
                    encryptionMethod = EncryptedXml.XmlEncAES192Url;
                    break;
                case 256:
                    encryptionMethod = EncryptedXml.XmlEncAES256Url;
                    break;
            }
        }
        else
        {
            // Throw an exception if the transform is not in the previous categories
            throw new CryptographicException("The specified algorithm is not supported for XML Encryption.");
        }

        edElement.EncryptionMethod = new EncryptionMethod(encryptionMethod);

        // Add the encrypted element data to the
        // EncryptedData object.
        edElement.CipherData.CipherValue = encryptedElement;

        ////////////////////////////////////////////////////
        // 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)
    {
        // Check the arguments.
        if (Doc == null)
            throw new ArgumentNullException("Doc");
        if (Alg == null)
            throw new ArgumentNullException("Alg");

        // Find the EncryptedData element in the XmlDocument.
        XmlElement encryptedElement = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;

        // If the EncryptedData element was not found, throw an exception.
        if (encryptedElement == null)
        {
            throw new XmlException("The EncryptedData element was not found.");
        }

        // Create an EncryptedData object and populate it.
        EncryptedData edElement = new EncryptedData();
        edElement.LoadXml(encryptedElement);

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

        // Decrypt the element using the symmetric key.
        byte[] rgbOutput = exml.DecryptData(edElement, Alg);

        // Replace the encryptedData element with the plaintext XML element.
        exml.ReplaceData(encryptedElement, rgbOutput);
    }
}

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)
            Return
        End Try

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


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

            ' 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)
        ' 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()

        Dim encryptedElement As Byte() = eXml.EncryptData(elementEncrypt, Alg, False)

        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Construct an EncryptedData object and populate
        ' it with the desired encryption information.
        '''''''''''''''''''''''''''''''''''''''''''''''''''

        Dim edElement As New EncryptedData()
        edElement.Type = EncryptedXml.XmlEncElementUrl

        ' Create an EncryptionMethod element so that the 
        ' receiver knows which algorithm to use for decryption.
        ' Determine what kind of algorithm is being used and
        ' supply the appropriate URL to the EncryptionMethod element.
        Dim encryptionMethod As String = Nothing

        If TypeOf Alg Is TripleDES Then
            encryptionMethod = EncryptedXml.XmlEncTripleDESUrl
        ElseIf TypeOf Alg Is DES Then
            encryptionMethod = EncryptedXml.XmlEncDESUrl
        ElseIf TypeOf Alg Is Aes Then
            Select Case Alg.KeySize
                Case 128
                    encryptionMethod = EncryptedXml.XmlEncAES128Url
                Case 192
                    encryptionMethod = EncryptedXml.XmlEncAES192Url
                Case 256
                    encryptionMethod = EncryptedXml.XmlEncAES256Url
            End Select
        Else
            ' Throw an exception if the transform is not in the previous categories
            Throw New CryptographicException("The specified algorithm is not supported for XML Encryption.")
        End If

        edElement.EncryptionMethod = New EncryptionMethod(encryptionMethod)

        ' Add the encrypted element data to the 
        ' EncryptedData object.
        edElement.CipherData.CipherValue = encryptedElement

        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' 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)
        ' 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
        ' Find the EncryptedData element in the XmlDocument.
        Dim encryptedElement As XmlElement = Doc.GetElementsByTagName("EncryptedData")(0)

        ' If the EncryptedData element was not found, throw an exception.
        If encryptedElement Is Nothing Then
            Throw New XmlException("The EncryptedData element was not found.")
        End If

        ' Create an EncryptedData object and populate it.
        Dim edElement As New EncryptedData()
        edElement.LoadXml(encryptedElement)

        ' Create a new EncryptedXml object.
        Dim exml As New EncryptedXml()

        ' Decrypt the element using the symmetric key.
        Dim rgbOutput As Byte() = exml.DecryptData(edElement, Alg)

        ' Replace the encryptedData element with the plaintext XML element.
        exml.ReplaceData(encryptedElement, rgbOutput)

    End Sub
End Module

注釈

タグは <EncryptionMethod> 、UNIFORM Resource Identifier (URI) を使用して、XML データの暗号化解除に使用する必要がある暗号化アルゴリズムを識別します。 クラスは EncryptionMethod 、 <EncryptionMethod> World Wide Web Consortium (W3C) XML 暗号化構文および処理 仕様で定義されているタグをカプセル化します。

クラスを EncryptionMethod 使用して、要素または 要素に EncryptedData 関連付けられている暗号化アルゴリズムを EncryptedKey 識別します。

W3C XML 暗号化の構文と処理 の仕様で定義されている URI 識別子のいずれかを使用します。 すべての URI 識別子は、 クラスの EncryptedXml 静的フィールドとしてアクセスできます。

コンストラクター

EncryptionMethod()	EncryptionMethod クラスの新しいインスタンスを初期化します。
EncryptionMethod(String)	アルゴリズムの URI (Uniform Resource Identifier) を指定して、EncryptionMethod クラスの新しいインスタンスを初期化します。

プロパティ

KeyAlgorithm	XML 暗号化に使用するアルゴリズムを記述する URI (Uniform Resource Identifier) を取得または設定します。
KeySize	XML 暗号化に使用するアルゴリズム キーのサイズを取得または設定します。

メソッド

Equals(Object)	指定されたオブジェクトが現在のオブジェクトと等しいかどうかを判断します。 (継承元 Object)
GetHashCode()	既定のハッシュ関数として機能します。 (継承元 Object)
GetType()	現在のインスタンスの Type を取得します。 (継承元 Object)
GetXml()	XmlElement クラスのインスタンスをカプセル化する EncryptionMethod オブジェクトを返します。
LoadXml(XmlElement)	指定された XmlElement オブジェクトを解析し、一致させる EncryptionMethod オブジェクトの内部状態を設定します。
MemberwiseClone()	現在の Object の簡易コピーを作成します。 (継承元 Object)
ToString()	現在のオブジェクトを表す文字列を返します。 (継承元 Object)