DataReference Classe

Référence

Définition

Espace de noms:: System.Security.Cryptography.Xml

Assembly:: System.Security.Cryptography.Xml.dll

Assembly:: System.Security.dll

Important

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Représente l'élément <DataReference> utilisé dans le chiffrement XML. Cette classe ne peut pas être héritée.

public ref class DataReference sealed : System::Security::Cryptography::Xml::EncryptedReference

public sealed class DataReference : System.Security.Cryptography.Xml.EncryptedReference

type DataReference = class
    inherit EncryptedReference

Public NotInheritable Class DataReference
Inherits EncryptedReference

Héritage: Object

EncryptedReference
DataReference

Exemples

L’exemple de code suivant montre comment utiliser la DataReference classe pour chiffrer et déchiffrer plusieurs éléments XML à l’aide de clés de session différentes.


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 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", "EncryptedElement1", rsaKey, "rsaKey");

            // Encrypt the "creditcard2" element.
            Encrypt(xmlDoc, "creditcard2", "EncryptedElement2", rsaKey, "rsaKey");

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

            // 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);
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
        finally
        {
            // Clear the RSA key.
            rsaKey.Clear();
        }

        Console.ReadLine();
    }

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

        ////////////////////////////////////////////////
        // 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;
        edElement.Id = EncryptionElementID;

        // 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);

        // Create a new DataReference element
        // for the KeyInfo element.  This optional
        // element specifies which EncryptedData
        // uses this key.  An XML document can have
        // multiple EncryptedData elements that use
        // different keys.
        DataReference dRef = new DataReference();

        // Specify the EncryptedData URI.
        dRef.Uri = "#" + EncryptionElementID;

        // Add the DataReference to the EncryptedKey.
        ek.AddReference(dRef);

        // 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();
    }
}

// To run this sample, place the following XML
// in a file called test.xml.  Put test.xml
// in the same directory as your compiled program.
//
//     <creditcard xmlns="myNamespace" Id="tag1">
//         <number>19834209</number>
//         <expiry>02/02/2002</expiry>
//     <creditcard2 xmlns="myNamespace" Id="tag2">
//         <number>19834208</number>
//         <expiry>02/02/2002</expiry>

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


        Try
            ' Encrypt the "creditcard" element.
            Encrypt(xmlDoc, "creditcard", "EncryptedElement1", rsaKey, "rsaKey")

            ' Encrypt the "creditcard2" element.
            Encrypt(xmlDoc, "creditcard2", "EncryptedElement2", rsaKey, "rsaKey")

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

            ' 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)
        Catch e As Exception
            Console.WriteLine(e.Message)
        Finally
            ' Clear the RSA key.
            rsaKey.Clear()
        End Try

        Console.ReadLine()

    End Sub

End Module 'Program


Module XMLEncryptionSubs

    Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncryptName As String, ByVal EncryptionElementID 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 ElementToEncryptName Is Nothing Then
            Throw New ArgumentNullException("ElementToEncrypt")
        End If
        If EncryptionElementID Is Nothing Then
            Throw New ArgumentNullException("EncryptionElementID")
        End If
        If Alg Is Nothing Then
            Throw New ArgumentNullException("Alg")
        End If
        If KeyName Is Nothing Then
            Throw New ArgumentNullException("KeyName")
        End If
        ''''''''''''''''''''''''''''''''''''''''''''''''
        ' Find the specified element in the XmlDocument
        ' object and create a new XmlElemnt object.
        ''''''''''''''''''''''''''''''''''''''''''''''''

        Dim elementToEncrypt As XmlElement = Doc.GetElementsByTagName(ElementToEncryptName)(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(elementToEncrypt, sessionKey, False)

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

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

        ' 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)

        ' Create a new DataReference element
        ' for the KeyInfo element.  This optional
        ' element specifies which EncryptedData 
        ' uses this key.  An XML document can have
        ' multiple EncryptedData elements that use
        ' different keys.
        Dim dRef As New DataReference()

        ' Specify the EncryptedData URI. 
        dRef.Uri = "#" + EncryptionElementID

        ' Add the DataReference to the EncryptedKey.
        ek.AddReference(dRef)

        ' 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)

    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 'XMLEncryptionSubs


' To run this sample, place the following XML
' in a file called test.xml.  Put test.xml
' in the same directory as your compiled program.
' 
'     <creditcard xmlns="myNamespace" Id="tag1">
'         <number>19834209</number>
'         <expiry>02/02/2002</expiry>
'     <creditcard2 xmlns="myNamespace" Id="tag2">
'         <number>19834208</number>
'         <expiry>02/02/2002</expiry>

Remarques

La DataReference classe représente l’élément <DataReference> qui contient l’emplacement des données chiffrées utilisées avec le chiffrement XML.

<DataReference> les éléments sont utilisés pour faire référence aux éléments chiffrés à <EncryptedData> l’aide de la clé définie dans l’élément englobant <EncryptedKey> . Plusieurs <DataReference> éléments peuvent se produire si plusieurs <EncryptedData> éléments existent qui sont chiffrés à l’aide de la même clé.

Pour plus d’informations sur les normes de chiffrement XML, consultez la syntaxe de chiffrement XML et la version de traitement.

Constructeurs

DataReference()	Initialise une nouvelle instance de la classe DataReference.
DataReference(String)	Initialise une nouvelle instance de la classe DataReference à l'aide de l'identificateur URI (Uniform Resource Identifier) fourni.
DataReference(String, TransformChain)	Initialise une nouvelle instance de la classe DataReference à l'aide de l'URI spécifié et d'un objet TransformChain.

Propriétés

CacheValid	Obtient une valeur qui indique si le cache est valide. (Hérité de EncryptedReference)
ReferenceType	Obtient ou définit un type de référence. (Hérité de EncryptedReference)
TransformChain	Obtient ou définit la chaîne de transformation d'un objet EncryptedReference. (Hérité de EncryptedReference)
Uri	Obtient ou définit l'URI d'un objet EncryptedReference. (Hérité de EncryptedReference)

Méthodes

AddTransform(Transform)	Ajoute un objet Transform à la chaîne de transformation actuelle d'un objet EncryptedReference. (Hérité de EncryptedReference)
Equals(Object)	Détermine si l'objet spécifié est égal à l'objet actuel. (Hérité de Object)
GetHashCode()	Fait office de fonction de hachage par défaut. (Hérité de Object)
GetType()	Obtient le Type de l'instance actuelle. (Hérité de Object)
GetXml()	Retourne la représentation XML d'un objet EncryptedReference. (Hérité de EncryptedReference)
LoadXml(XmlElement)	Charge un élément XML dans un objet EncryptedReference. (Hérité de EncryptedReference)
MemberwiseClone()	Crée une copie superficielle du Object actuel. (Hérité de Object)
ToString()	Retourne une chaîne qui représente l'objet actuel. (Hérité de Object)

S’applique à