KeyReference Classe
Definizione
Importante
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Rappresenta l'elemento <KeyReference> utilizzato nella crittografia XML. La classe non può essere ereditata.
public ref class KeyReference sealed : System::Security::Cryptography::Xml::EncryptedReferencepublic sealed class KeyReference : System.Security.Cryptography.Xml.EncryptedReferencetype KeyReference = class
inherit EncryptedReferencePublic NotInheritable Class KeyReference
Inherits EncryptedReference- Ereditarietà
Esempio
Nell'esempio di codice seguente viene illustrato come usare un oggetto durante la crittografia di un KeyReference documento 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>
Commenti
La KeyReference classe rappresenta l'elemento <KeyReference> che contiene informazioni sulla posizione di una chiave crittografata.
Usare l'elemento <KeyReference> per fare riferimento agli <EncryptedKey> elementi crittografati usando la chiave definita nell'elemento racchiuso <EncryptedKey> . È possibile usare più elementi quando esistono più <KeyReference><EncryptedKey> elementi crittografati usando la stessa chiave.
È possibile includere informazioni aggiuntive, ad esempio trasformazioni XPath, trasformazioni di decompressione o informazioni su come recuperare gli elementi da una struttura di archiviazione documenti per aiutare l'applicazione di decrittografia.
Per altre informazioni sugli standard di crittografia XML, la sintassi e la specifica di elaborazione XML Wide Web Consortium (W3C).
Costruttori
| KeyReference() |
Inizializza una nuova istanza della classe KeyReference per la crittografia XML. |
| KeyReference(String) |
Inizializza una nuova istanza della classe KeyReference per la crittografia XML mediante l'URI (Uniform Resource Identifier) fornito. |
| KeyReference(String, TransformChain) |
Consente di inizializzare una nuova istanza della classe KeyReference per la crittografia XML mediante l'URI (Uniform Resource Identifier) specificato e un oggetto TransformChain. |
Proprietà
| CacheValid |
Ottiene un valore che indica se la cache è valida. (Ereditato da EncryptedReference) |
| ReferenceType |
Ottiene o imposta il tipo di riferimento. (Ereditato da EncryptedReference) |
| TransformChain |
Ottiene o imposta la catena delle trasformazioni di un oggetto EncryptedReference. (Ereditato da EncryptedReference) |
| Uri |
Ottiene o imposta l'URI (Uniform Resource Identifier) di un oggetto EncryptedReference. (Ereditato da EncryptedReference) |
Metodi
| AddTransform(Transform) |
Consente di aggiungere un oggetto Transform alla catena di trasformazioni corrente di un oggetto EncryptedReference. (Ereditato da EncryptedReference) |
| Equals(Object) |
Determina se l'oggetto specificato è uguale all'oggetto corrente. (Ereditato da Object) |
| GetHashCode() |
Funge da funzione hash predefinita. (Ereditato da Object) |
| GetType() |
Ottiene l'oggetto Type dell'istanza corrente. (Ereditato da Object) |
| GetXml() |
Restituisce la rappresentazione XML dell'oggetto EncryptedReference. (Ereditato da EncryptedReference) |
| LoadXml(XmlElement) |
Consente di caricare un elemento XML in un oggetto EncryptedReference. (Ereditato da EncryptedReference) |
| MemberwiseClone() |
Crea una copia superficiale dell'oggetto Object corrente. (Ereditato da Object) |
| ToString() |
Restituisce una stringa che rappresenta l'oggetto corrente. (Ereditato da Object) |
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