KeyReference Třída

Definice

Obor názvů:

System.Security.Cryptography.Xml

Sestavení:

System.Security.Cryptography.Xml.dll

Balíček:

System.Security.Cryptography.Xml v8.0.0

Zdroj:

KeyReference.cs

<KeyReference> Představuje prvek použitý v šifrování XML. Tuto třídu nelze dědit.

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

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

type KeyReference = class
    inherit EncryptedReference

Public NotInheritable Class KeyReference
Inherits EncryptedReference

Dědičnost

Object

EncryptedReference

KeyReference

Příklady

Následující příklad kódu ukazuje, jak použít KeyReference objekt při šifrování dokumentu XML.

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();

        ek.Id = "keyID";

        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 KeyReference object.
        // Use the uri of the encrypted key.
        KeyReference kryRef = new KeyReference("#keyID");

        ek.AddReference(kryRef);

        // 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()

        ek.Id = "keyID"

        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 KeyReference object.
        ' Use the uri of the encrypted key.
        Dim kryRef As New KeyReference("#keyID")

        ek.AddReference(kryRef)

        ' 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>

Poznámky

Třída KeyReference představuje <KeyReference> prvek, který obsahuje informace o umístění šifrovaného klíče.

<KeyReference> Použijte element k odkazování na <EncryptedKey> elementy, které byly zašifrovány pomocí klíče definovaného v nadřazeném <EncryptedKey> elementu. Pokud existuje více <EncryptedKey> elementů, které jsou šifrované pomocí stejného klíče, můžete použít více <KeyReference> prvků.

Můžete zahrnout další informace, jako jsou transformace XPath, dekompresní transformace nebo informace o tom, jak načíst prvky z úložiště dokumentů, které pomáhají dešifrovací aplikaci.

Další informace o standardech šifrování XML specifikace W3C (World Wide Web Consortium) XML Encryption Syntax and Processing .

Konstruktory

KeyReference()	Inicializuje novou instanci KeyReference třídy šifrování XML.
KeyReference(String)	Inicializuje novou instanci KeyReference třídy pro šifrování XML pomocí zadaného identifikátoru URI (Uniform Resource Identifier).
KeyReference(String, TransformChain)	Inicializuje novou instanci KeyReference třídy pro šifrování XML pomocí zadaného identifikátoru URI (Uniform Resource Identifier) a objektu TransformChain .

Vlastnosti

CacheValid	Získá hodnotu, která označuje, zda je mezipaměť platná. (Zděděno od EncryptedReference)
ReferenceType	Získá nebo nastaví typ odkazu. (Zděděno od EncryptedReference)
TransformChain	Získá nebo nastaví transformační řetězec objektu EncryptedReference . (Zděděno od EncryptedReference)
Uri	Získá nebo nastaví identifikátor URI (Uniform Resource Identifier) objektu EncryptedReference . (Zděděno od EncryptedReference)

Metody

AddTransform(Transform)	Transform Přidá objekt do aktuálního řetězce transformace objektuEncryptedReference. (Zděděno od EncryptedReference)
Equals(Object)	Určí, zda se zadaný objekt rovná aktuálnímu objektu. (Zděděno od Object)
GetHashCode()	Slouží jako výchozí hashovací funkce. (Zděděno od Object)
GetType()	Type Získá z aktuální instance. (Zděděno od Object)
GetXml()	Vrátí reprezentaci XML objektu EncryptedReference . (Zděděno od EncryptedReference)
LoadXml(XmlElement)	Načte element XML do objektu EncryptedReference . (Zděděno od EncryptedReference)
MemberwiseClone()	Vytvoří mělkou kopii aktuálního Objectsouboru . (Zděděno od Object)
ToString()	Vrátí řetězec, který představuje aktuální objekt. (Zděděno od Object)