EncryptedXml.DecryptDocument Méthode

public:
 void DecryptDocument();

public void DecryptDocument ();

member this.DecryptDocument : unit -> unit

Public Sub DecryptDocument ()

Exceptions

Exemples

L’exemple de code suivant montre comment chiffrer un document XML à l’aide d’une clé asymétrique. Cet exemple crée une clé de session symétrique pour chiffrer le document, puis utilise la clé asymétrique pour incorporer une version chiffrée de la clé de session dans le document XML.

#using <System.Xml.dll>
#using <System.Security.dll>
#using <System.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, RSA^ 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
   // a new random symmetric key.
   //////////////////////////////////////////////////
   // Create a 256 bit Aes key.
   Aes^ sessionKey = Aes::Create();
   sessionKey->KeySize = 256;
   EncryptedXml^ eXml = gcnew EncryptedXml;
   array<Byte>^encryptedElement = eXml->EncryptData( elementToEncrypt, sessionKey, 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.
   edElement->EncryptionMethod = gcnew EncryptionMethod( EncryptedXml::XmlEncAES256Url );

   // Encrypt the session key and add it to an EncryptedKey element.
   EncryptedKey^ ek = gcnew EncryptedKey;
   array<Byte>^encryptedKey = EncryptedXml::EncryptKey( sessionKey->Key, Alg, false );
   ek->CipherData = gcnew CipherData( encryptedKey );
   ek->EncryptionMethod = gcnew EncryptionMethod( EncryptedXml::XmlEncRSA15Url );

   // Set the KeyInfo element to specify the
   // name of the RSA key.
   // Create a new KeyInfo element.
   edElement->KeyInfo = gcnew KeyInfo;

   // Create a new KeyInfoName element.
   KeyInfoName^ kin = gcnew KeyInfoName;

   // Specify a name for the key.
   kin->Value = KeyName;

   // Add the KeyInfoName element to the
   // EncryptedKey object.
   ek->KeyInfo->AddClause( kin );

   // Add the encrypted key to the
   // EncryptedData object.
   edElement->KeyInfo->AddClause( gcnew KeyInfoEncryptedKey( ek ) );

   // 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, RSA^ 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 a key-name mapping.
   // This method can only decrypt documents
   // that present the specified key name.
   exml->AddKeyNameMapping( KeyName, Alg );

   // Decrypt the element.
   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 );
      return 0;
   }


   // Create a new RSA key.  This key will encrypt a symmetric key,
   // which will then be imbedded in the XML document.
   RSA^ rsaKey = RSA::Create();
   try
   {

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

      // Display the encrypted XML to the console.
      Console::WriteLine( L"Encrypted XML:" );
      Console::WriteLine();
      Console::WriteLine( xmlDoc->OuterXml );
      xmlDoc->Save( L"test.xml" );

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

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

      // Clear the RSA key.
      rsaKey->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 RSA key.  This key will encrypt a symmetric key,
        // which will then be imbedded in the XML document.
        RSA rsaKey = RSA.Create();

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

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

            // Decrypt the "creditcard" element.
            Decrypt(xmlDoc, rsaKey, "rsaKey");
            xmlDoc.Save("test.xml");

            // 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 RSA key.
            rsaKey.Clear();
        }
    }

    public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, RSA 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
        // a new random symmetric key.
        //////////////////////////////////////////////////

        // Create a 256 bit Aes key.
        Aes sessionKey = Aes.Create();
        sessionKey.KeySize = 256;

        EncryptedXml eXml = new EncryptedXml();

        byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, sessionKey, 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.

        edElement.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncAES256Url);

        // Encrypt the session key and add it to an EncryptedKey element.
        EncryptedKey ek = new EncryptedKey();

        byte[] encryptedKey = EncryptedXml.EncryptKey(sessionKey.Key, Alg, false);

        ek.CipherData = new CipherData(encryptedKey);

        ek.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncRSA15Url);

        // Set the KeyInfo element to specify the
        // name of the RSA key.

        // Create a new KeyInfo element.
        edElement.KeyInfo = new KeyInfo();

        // Create a new KeyInfoName element.
        KeyInfoName kin = new KeyInfoName();

        // Specify a name for the key.
        kin.Value = KeyName;

        // Add the KeyInfoName element to the
        // EncryptedKey object.
        ek.KeyInfo.AddClause(kin);

        // Add the encrypted key to the
        // EncryptedData object.

        edElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(ek));

        // 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, RSA 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 a key-name mapping.
        // This method can only decrypt documents
        // that present the specified key name.
        exml.AddKeyNameMapping(KeyName, Alg);

        // Decrypt the element.
        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)
            Return
        End Try

        ' Create a new RSA key.  This key will encrypt a symmetric key,
        ' which will then be imbedded in the XML document.  
        Dim rsaKey = RSA = RSA.Create()


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

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

            ' Decrypt the "creditcard" element.
            Decrypt(xmlDoc, rsaKey, "rsaKey")

            ' Display the encrypted XML to the console.
            Console.WriteLine()
            Console.WriteLine("Decrypted XML:")
            Console.WriteLine()
            Console.WriteLine(xmlDoc.OuterXml)
            xmlDoc.Save("test.xml")
        Catch e As Exception
            Console.WriteLine(e.Message)
        Finally
            ' Clear the RSA key.
            rsaKey.Clear()
        End Try

    End Sub


    Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncrypt As String, ByVal Alg As RSA, 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 
        ' a new random symmetric key.
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' Create a 256 bit Aes key.
        Dim sessionKey As Aes = Aes.Create()
        sessionKey.KeySize = 256

        Dim eXml As New EncryptedXml()

        Dim encryptedElement As Byte() = eXml.EncryptData(elementEncrypt, sessionKey, 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.
        edElement.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncAES256Url)

        ' Encrypt the session key and add it to an EncryptedKey element.
        Dim ek As New EncryptedKey()

        Dim encryptedKey As Byte() = EncryptedXml.EncryptKey(sessionKey.Key, Alg, False)

        ek.CipherData = New CipherData(encryptedKey)

        ek.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncRSA15Url)

        ' Set the KeyInfo element to specify the
        ' name of the RSA key.
        ' Create a new KeyInfo element.
        edElement.KeyInfo = New KeyInfo()

        ' Create a new KeyInfoName element.
        Dim kin As New KeyInfoName()

        ' Specify a name for the key.
        kin.Value = KeyName

        ' Add the KeyInfoName element to the 
        ' EncryptedKey object.
        ek.KeyInfo.AddClause(kin)

        ' Add the encrypted key to the 
        ' EncryptedData object.
        edElement.KeyInfo.AddClause(New KeyInfoEncryptedKey(ek))

        ' 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 RSA, 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 a key-name mapping.
        ' This method can only decrypt documents
        ' that present the specified key name.
        exml.AddKeyNameMapping(KeyName, Alg)

        ' Decrypt the element.
        exml.DecryptDocument()

    End Sub
End Module

L’exemple de code suivant montre comment chiffrer un document XML à l’aide d’un certificat X.509. Cet exemple crée une clé de session symétrique pour chiffrer le document, puis utilise le certificat X.509 pour incorporer une version chiffrée de la clé de session dans le document XML.

#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;
using namespace System::Security::Cryptography::X509Certificates;
static void Encrypt( XmlDocument^ Doc, String^ ElementToEncrypt, X509Certificate2^ Cert )
{

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

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

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


   ////////////////////////////////////////////////
   // 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
   // X.509 Certificate.
   //////////////////////////////////////////////////
   EncryptedXml^ eXml = gcnew EncryptedXml;

   // Encrypt the element.
   EncryptedData^ edElement = eXml->Encrypt( elementToEncrypt, Cert );

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

static void Decrypt( XmlDocument^ Doc )
{

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


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

   // 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 );
      return 0;
   }


   // Create a new X509Certificate2 object by loading
   // an X.509 certificate file.  To use XML encryption
   // with an X.509 certificate, use an X509Certificate2
   // object to encrypt, but use a certificate in a certificate
   // store to decrypt.
   // You can create a new test certificate file using the
   // makecert.exe tool.
   // Create an X509Certificate2 object for encryption.
   X509Certificate2^ cert = gcnew X509Certificate2( L"test.pfx" );

   // Put the certificate in certificate store for decryption.
   X509Store^ store = gcnew X509Store( StoreLocation::CurrentUser );
   store->Open( OpenFlags::ReadWrite );
   store->Add( cert );
   store->Close();
   try
   {

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

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

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

      // 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 );
   }

   return 1;
}

using System;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Security.Cryptography.X509Certificates;

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 X509Certificate2 object by loading
        // an X.509 certificate file.  To use XML encryption
        // with an X.509 certificate, use an X509Certificate2
        // object to encrypt, but use a certificate in a certificate
        // store to decrypt.

        // You can create a new test certificate file using the
        // makecert.exe tool.

        // Create an X509Certificate2 object for encryption.
        X509Certificate2 cert = new X509Certificate2("test.pfx");

        // Put the certificate in certificate store for decryption.
        X509Store store = new X509Store(StoreLocation.CurrentUser);

        store.Open(OpenFlags.ReadWrite);

        store.Add(cert);

        store.Close();

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

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

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

            // 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);
        }
    }

    public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, X509Certificate2 Cert)
    {
        // Check the arguments.
        if (Doc == null)
            throw new ArgumentNullException("Doc");
        if (ElementToEncrypt == null)
            throw new ArgumentNullException("ElementToEncrypt");
        if (Cert == null)
            throw new ArgumentNullException("Cert");

        ////////////////////////////////////////////////
        // 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
        // X.509 Certificate.
        //////////////////////////////////////////////////

        EncryptedXml eXml = new EncryptedXml();

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

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

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

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

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

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

Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Security.Cryptography.X509Certificates



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 X509Certificate2 object by loading
        ' an X.509 certificate file.  To use XML encryption 
        ' with an X.509 certificate, use an X509Certificate2 
        ' object to encrypt, but use a certificate in a certificate
        ' store to decrypt.
        ' You can create a new test certificate file using the 
        ' makecert.exe tool.
        ' Create an X509Certificate2 object for encryption.
        Dim cert As New X509Certificate2("test.pfx")

        ' Put the certificate in certificate store for decryption.  
        Dim store As New X509Store(StoreLocation.CurrentUser)

        store.Open(OpenFlags.ReadWrite)

        store.Add(cert)

        store.Close()


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

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

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

            ' 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)
        End Try

    End Sub


    Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncrypt As String, ByVal Cert As X509Certificate2)
        ' 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 Cert Is Nothing Then
            Throw New ArgumentNullException("Cert")
        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 
        ' X.509 Certificate.
        '''''''''''''''''''''''''''''''''''''''''''''''''''
        Dim eXml As New EncryptedXml()

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


        '''''''''''''''''''''''''''''''''''''''''''''''''''
        ' 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)
        ' Check the arguments.  
        If Doc Is Nothing Then
            Throw New ArgumentNullException("Doc")
        End If
        ' Create a new EncryptedXml object.
        Dim exml As New EncryptedXml(Doc)

        ' Decrypt the XML document.
        exml.DecryptDocument()

    End Sub
End Module

L’exemple de code suivant montre comment déchiffrer une balise de haut niveau <EncryptedData> qui contient une autre balise chiffrée <EncryptedData> .

static void Decrypt(XmlDocument Doc, RSA 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.
    var exml = new EncryptedXml(Doc);

    // Add a key-name mapping.
    // This method can only decrypt documents
    // that present the specified key name.
    exml.AddKeyNameMapping(KeyName, Alg);

    while (Doc.GetElementsByTagName("EncryptedData", EncryptedXml.XmlEncNamespaceUrl).Count > 0)
    {
        // Decrypt the element.
        exml.DecryptDocument();
    }
}

Sub Decrypt(ByVal Doc As XmlDocument, ByVal Alg As RSA, 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 a key-name mapping.
    ' This method can only decrypt documents
    ' that present the specified key name.
    exml.AddKeyNameMapping(KeyName, Alg)

    While Doc.GetElementsByTagName("EncryptedData", EncryptedXml.XmlEncNamespaceUrl).Count > 0
        ' Decrypt the element.
        exml.DecryptDocument()
    End While

End Sub

Remarques

La DecryptDocument méthode déchiffre tous les <EncryptedData> éléments du document XML chargé pendant l’initialisation. Après avoir appelé cette méthode, tous les <EncryptedData> éléments du document sont remplacés par des versions de texte brut.

La DecryptDocument méthode déchiffre uniquement les éléments de niveau <EncryptedData> supérieur. Si vous devez déchiffrer un document surchiffré (document chiffré plusieurs fois), vous devez appeler la DecryptDocument méthode à plusieurs reprises jusqu’à ce que tous les <EncryptedData> éléments aient été déchiffrés.

Pour utiliser le chiffrement XML avec des certificats X.509, vous devez avoir le fournisseur de chiffrement Microsoft Amélioré installé et le certificat X.509 doit utiliser le fournisseur amélioré. Si le fournisseur de chiffrement microsoft amélioré n’est pas installé ou si le certificat X.509 n’utilise pas le fournisseur amélioré, un CryptographicException avec une « erreur inconnue » est généré lorsque vous déchiffrez un document XML.

S’applique à