DataReference Classe
Definição
Importante
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Representa o elemento <DataReference> usado na criptografia XML. Essa classe não pode ser herdada.
public ref class DataReference sealed : System::Security::Cryptography::Xml::EncryptedReferencepublic sealed class DataReference : System.Security.Cryptography.Xml.EncryptedReferencetype DataReference = class
inherit EncryptedReferencePublic NotInheritable Class DataReference
Inherits EncryptedReference- Herança
Exemplos
O exemplo de código a seguir demonstra como usar a DataReference classe para criptografar e descriptografar vários elementos XML usando chaves de sessão diferentes.
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>
Comentários
A DataReference classe representa o <DataReference> elemento que contém o local dos dados criptografados usados com criptografia XML.
<DataReference> os elementos são usados para se referir a <EncryptedData> elementos que foram criptografados usando a chave definida no elemento delimitamento <EncryptedKey> . Vários <DataReference> elementos poderão ocorrer se houver vários <EncryptedData> elementos criptografados usando a mesma chave.
Para obter mais informações sobre os padrões de criptografia XML, consulte a sintaxe de criptografia XML e a versão de processamento.
Construtores
| DataReference() |
Inicializa uma nova instância da classe DataReference. |
| DataReference(String) |
Inicializa uma nova instância da classe DataReference usando o URI (Uniform Resource Identifier) especificado. |
| DataReference(String, TransformChain) |
Inicializa uma nova instância da classe DataReference usando o URI (Uniform Resource Identifier) e um objeto TransformChain especificados. |
Propriedades
| CacheValid |
Obtém um valor que indica se o cache é válido. (Herdado de EncryptedReference) |
| ReferenceType |
Obtém ou define um tipo de referência. (Herdado de EncryptedReference) |
| TransformChain |
Obtém ou define a cadeia de transformação de um objeto EncryptedReference. (Herdado de EncryptedReference) |
| Uri |
Obtém ou define o URI (Uniform Resource Identifier) de um objeto EncryptedReference. (Herdado de EncryptedReference) |
Métodos
| AddTransform(Transform) |
Adiciona um objeto Transform à cadeia de transformação atual de um objeto EncryptedReference. (Herdado de EncryptedReference) |
| Equals(Object) |
Determina se o objeto especificado é igual ao objeto atual. (Herdado de Object) |
| GetHashCode() |
Serve como a função de hash padrão. (Herdado de Object) |
| GetType() |
Obtém o Type da instância atual. (Herdado de Object) |
| GetXml() |
Retorna a representação XML de um objeto EncryptedReference. (Herdado de EncryptedReference) |
| LoadXml(XmlElement) |
Carrega um elemento XML em um objeto EncryptedReference. (Herdado de EncryptedReference) |
| MemberwiseClone() |
Cria uma cópia superficial do Object atual. (Herdado de Object) |
| ToString() |
Retorna uma cadeia de caracteres que representa o objeto atual. (Herdado de Object) |