EncryptedXml.DecryptData(EncryptedData, SymmetricAlgorithm) Método
Definição
Importante
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Descriptografa um elemento <EncryptedData> usando o algoritmo simétrico especificado.
public:
cli::array <System::Byte> ^ DecryptData(System::Security::Cryptography::Xml::EncryptedData ^ encryptedData, System::Security::Cryptography::SymmetricAlgorithm ^ symmetricAlgorithm);public byte[] DecryptData (System.Security.Cryptography.Xml.EncryptedData encryptedData, System.Security.Cryptography.SymmetricAlgorithm symmetricAlgorithm);member this.DecryptData : System.Security.Cryptography.Xml.EncryptedData * System.Security.Cryptography.SymmetricAlgorithm -> byte[]Public Function DecryptData (encryptedData As EncryptedData, symmetricAlgorithm As SymmetricAlgorithm) As Byte()Parâmetros
- encryptedData
- EncryptedData
Os dados a serem descriptografados.
- symmetricAlgorithm
- SymmetricAlgorithm
A chave simétrica usada para descriptografar encryptedData.
Retornos
Byte[]
Uma matriz de bytes que contém o texto sem formatação descriptografado bruto.
Exceções
O valor do parâmetro encryptedData é null.
- ou -
O valor do parâmetro symmetricAlgorithm é null.
Exemplos
O exemplo de código a seguir demonstra como criptografar um documento XML usando uma chave simétrica. Este exemplo não inclui nenhuma informação de chave no documento XML criptografado.
#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;
static void Encrypt( XmlDocument^ Doc, String^ ElementToEncrypt, SymmetricAlgorithm^ Alg )
{
// 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
// symmetric key.
//////////////////////////////////////////////////
EncryptedXml^ eXml = gcnew EncryptedXml;
array<Byte>^encryptedElement = eXml->EncryptData( elementToEncrypt, Alg, 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.
// Determine what kind of algorithm is being used and
// supply the appropriate URL to the EncryptionMethod element.
String^ encryptionMethod = nullptr;
if ( dynamic_cast<TripleDES^>(Alg) )
{
encryptionMethod = EncryptedXml::XmlEncTripleDESUrl;
}
else
if ( dynamic_cast<DES^>(Alg) )
{
encryptionMethod = EncryptedXml::XmlEncDESUrl;
}
else
if ( dynamic_cast<Aes^>(Alg) )
{
switch ( Alg->KeySize )
{
case 128:
encryptionMethod = EncryptedXml::XmlEncAES128Url;
break;
case 192:
encryptionMethod = EncryptedXml::XmlEncAES192Url;
break;
case 256:
encryptionMethod = EncryptedXml::XmlEncAES256Url;
break;
}
}
else
{
// Throw an exception if the transform is not in the previous categories
throw gcnew CryptographicException( L"The specified algorithm is not supported for XML Encryption." );
}
edElement->EncryptionMethod = gcnew EncryptionMethod( encryptionMethod );
// 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, SymmetricAlgorithm^ Alg )
{
// Check the arguments.
if ( Doc == nullptr )
throw gcnew ArgumentNullException( L"Doc" );
if ( Alg == nullptr )
throw gcnew ArgumentNullException( L"Alg" );
// Find the EncryptedData element in the XmlDocument.
XmlElement^ encryptedElement = dynamic_cast<XmlElement^>(Doc->GetElementsByTagName( L"EncryptedData" )->Item( 0 ));
// If the EncryptedData element was not found, throw an exception.
if ( encryptedElement == nullptr )
{
throw gcnew XmlException( L"The EncryptedData element was not found." );
}
// Create an EncryptedData object and populate it.
EncryptedData^ edElement = gcnew EncryptedData;
edElement->LoadXml( encryptedElement );
// Create a new EncryptedXml object.
EncryptedXml^ exml = gcnew EncryptedXml;
// Decrypt the element using the symmetric key.
array<Byte>^rgbOutput = exml->DecryptData( edElement, Alg );
// Replace the encryptedData element with the plaintext XML element.
exml->ReplaceData( encryptedElement, rgbOutput );
}
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 TripleDES key.
TripleDESCryptoServiceProvider^ tDESkey = gcnew TripleDESCryptoServiceProvider;
try
{
// Encrypt the "creditcard" element.
Encrypt( xmlDoc, L"creditcard", tDESkey );
// Display the encrypted XML to the console.
Console::WriteLine( L"Encrypted XML:" );
Console::WriteLine();
Console::WriteLine( xmlDoc->OuterXml );
// Decrypt the "creditcard" element.
Decrypt( xmlDoc, tDESkey );
// 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 );
}
finally
{
// Clear the TripleDES key.
tDESkey->Clear();
}
}
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 TripleDES key.
TripleDESCryptoServiceProvider tDESkey = new TripleDESCryptoServiceProvider();
try
{
// Encrypt the "creditcard" element.
Encrypt(xmlDoc, "creditcard", tDESkey);
// Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlDoc.OuterXml);
// Decrypt the "creditcard" element.
Decrypt(xmlDoc, tDESkey);
// 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 TripleDES key.
tDESkey.Clear();
}
}
public static void Encrypt(XmlDocument Doc, string ElementToEncrypt, SymmetricAlgorithm Alg)
{
// 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
// symmetric key.
//////////////////////////////////////////////////
EncryptedXml eXml = new EncryptedXml();
byte[] encryptedElement = eXml.EncryptData(elementToEncrypt, Alg, 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.
// Determine what kind of algorithm is being used and
// supply the appropriate URL to the EncryptionMethod element.
string encryptionMethod = null;
if (Alg is TripleDES)
{
encryptionMethod = EncryptedXml.XmlEncTripleDESUrl;
}
else if (Alg is DES)
{
encryptionMethod = EncryptedXml.XmlEncDESUrl;
}
else if (Alg is Aes)
{
switch (Alg.KeySize)
{
case 128:
encryptionMethod = EncryptedXml.XmlEncAES128Url;
break;
case 192:
encryptionMethod = EncryptedXml.XmlEncAES192Url;
break;
case 256:
encryptionMethod = EncryptedXml.XmlEncAES256Url;
break;
}
}
else
{
// Throw an exception if the transform is not in the previous categories
throw new CryptographicException("The specified algorithm is not supported for XML Encryption.");
}
edElement.EncryptionMethod = new EncryptionMethod(encryptionMethod);
// 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, SymmetricAlgorithm Alg)
{
// Check the arguments.
if (Doc == null)
throw new ArgumentNullException("Doc");
if (Alg == null)
throw new ArgumentNullException("Alg");
// Find the EncryptedData element in the XmlDocument.
XmlElement encryptedElement = Doc.GetElementsByTagName("EncryptedData")[0] as XmlElement;
// If the EncryptedData element was not found, throw an exception.
if (encryptedElement == null)
{
throw new XmlException("The EncryptedData element was not found.");
}
// Create an EncryptedData object and populate it.
EncryptedData edElement = new EncryptedData();
edElement.LoadXml(encryptedElement);
// Create a new EncryptedXml object.
EncryptedXml exml = new EncryptedXml();
// Decrypt the element using the symmetric key.
byte[] rgbOutput = exml.DecryptData(edElement, Alg);
// Replace the encryptedData element with the plaintext XML element.
exml.ReplaceData(encryptedElement, rgbOutput);
}
}
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 TripleDES key.
Dim tDESkey As New TripleDESCryptoServiceProvider()
Try
' Encrypt the "creditcard" element.
Encrypt(xmlDoc, "creditcard", tDESkey)
' Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:")
Console.WriteLine()
Console.WriteLine(xmlDoc.OuterXml)
' Decrypt the "creditcard" element.
Decrypt(xmlDoc, tDESkey)
' 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 TripleDES key.
tDESkey.Clear()
End Try
End Sub
Sub Encrypt(ByVal Doc As XmlDocument, ByVal ElementToEncrypt As String, ByVal Alg As SymmetricAlgorithm)
' 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
' symmetric key.
'''''''''''''''''''''''''''''''''''''''''''''''''''
Dim eXml As New EncryptedXml()
Dim encryptedElement As Byte() = eXml.EncryptData(elementEncrypt, Alg, 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.
' Determine what kind of algorithm is being used and
' supply the appropriate URL to the EncryptionMethod element.
Dim encryptionMethod As String = Nothing
If TypeOf Alg Is TripleDES Then
encryptionMethod = EncryptedXml.XmlEncTripleDESUrl
ElseIf TypeOf Alg Is DES Then
encryptionMethod = EncryptedXml.XmlEncDESUrl
ElseIf TypeOf Alg Is Aes Then
Select Case Alg.KeySize
Case 128
encryptionMethod = EncryptedXml.XmlEncAES128Url
Case 192
encryptionMethod = EncryptedXml.XmlEncAES192Url
Case 256
encryptionMethod = EncryptedXml.XmlEncAES256Url
End Select
Else
' Throw an exception if the transform is not in the previous categories
Throw New CryptographicException("The specified algorithm is not supported for XML Encryption.")
End If
edElement.EncryptionMethod = New EncryptionMethod(encryptionMethod)
' 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 SymmetricAlgorithm)
' 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
' Find the EncryptedData element in the XmlDocument.
Dim encryptedElement As XmlElement = Doc.GetElementsByTagName("EncryptedData")(0)
' If the EncryptedData element was not found, throw an exception.
If encryptedElement Is Nothing Then
Throw New XmlException("The EncryptedData element was not found.")
End If
' Create an EncryptedData object and populate it.
Dim edElement As New EncryptedData()
edElement.LoadXml(encryptedElement)
' Create a new EncryptedXml object.
Dim exml As New EncryptedXml()
' Decrypt the element using the symmetric key.
Dim rgbOutput As Byte() = exml.DecryptData(edElement, Alg)
' Replace the encryptedData element with the plaintext XML element.
exml.ReplaceData(encryptedElement, rgbOutput)
End Sub
End Module
Comentários
Use o DecryptData método para descriptografar um EncryptedData elemento usando uma chave simétrica.
Observe que o DecryptData método descriptografa apenas marcas de nível <EncryptedData> superior. Nos casos em que uma ou mais <EncryptedData> marcas foram criptografadas e estão contidas em marcas de nível <EncryptedData> mais alto, você pode chamar o DecryptDocument método separadamente para cada uma delas. Consulte o DecryptDocument método para obter um exemplo de código.
Aplica-se a
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