EncryptionMethod Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Encapsulates the encryption algorithm used for XML encryption.
public ref class EncryptionMethodpublic class EncryptionMethodtype EncryptionMethod = classPublic Class EncryptionMethod- Inheritance
-
EncryptionMethod
Examples
The following code example demonstrates how to create a simple utility class that uses the TripleDES algorithm to encrypt an XML document.
#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;
ref class TrippleDESDocumentEncryption
{
protected:
XmlDocument^ docValue;
TripleDES^ algValue;
public:
TrippleDESDocumentEncryption( XmlDocument^ Doc, TripleDES^ Key )
{
if ( Doc != nullptr )
{
docValue = Doc;
}
else
{
throw gcnew ArgumentNullException( L"Doc" );
}
if ( Key != nullptr )
{
algValue = Key;
}
else
{
throw gcnew ArgumentNullException( L"Key" );
}
}
property XmlDocument^ Doc
{
XmlDocument^ get()
{
return docValue;
}
void set( XmlDocument^ value )
{
docValue = value;
}
}
property TripleDES^ Alg
{
TripleDES^ get()
{
return algValue;
}
void set( TripleDES^ value )
{
algValue = value;
}
}
void Clear()
{
if ( algValue != nullptr )
{
algValue->Clear();
}
else
{
throw gcnew Exception( L"No TripleDES key was found to clear." );
}
}
void Encrypt( String^ Element )
{
// Find the element by name and create a new
// XmlElement object.
XmlElement^ inputElement = dynamic_cast<XmlElement^>(docValue->GetElementsByTagName( Element )->Item( 0 ));
// If the element was not found, throw an exception.
if ( inputElement == nullptr )
{
throw gcnew Exception( L"The element was not found." );
}
// Create a new EncryptedXml object.
EncryptedXml^ exml = gcnew EncryptedXml( docValue );
// Encrypt the element using the symmetric key.
array<Byte>^rgbOutput = exml->EncryptData( inputElement, algValue, false );
// Create an EncryptedData object and populate it.
EncryptedData^ ed = gcnew EncryptedData;
// Specify the namespace URI for XML encryption elements.
ed->Type = EncryptedXml::XmlEncElementUrl;
// Specify the namespace URI for the TrippleDES algorithm.
ed->EncryptionMethod = gcnew EncryptionMethod( EncryptedXml::XmlEncTripleDESUrl );
// Create a CipherData element.
ed->CipherData = gcnew CipherData;
// Set the CipherData element to the value of the encrypted XML element.
ed->CipherData->CipherValue = rgbOutput;
// Replace the plaintext XML elemnt with an EncryptedData element.
EncryptedXml::ReplaceElement( inputElement, ed, false );
}
void Decrypt()
{
// XmlElement object.
XmlElement^ encryptedElement = dynamic_cast<XmlElement^>(docValue->GetElementsByTagName( L"EncryptedData" )->Item( 0 ));
// If the EncryptedData element was not found, throw an exception.
if ( encryptedElement == nullptr )
{
throw gcnew Exception( L"The EncryptedData element was not found." );
}
// Create an EncryptedData object and populate it.
EncryptedData^ ed = gcnew EncryptedData;
ed->LoadXml( encryptedElement );
// Create a new EncryptedXml object.
EncryptedXml^ exml = gcnew EncryptedXml;
// Decrypt the element using the symmetric key.
array<Byte>^rgbOutput = exml->DecryptData( ed, algValue );
// Replace the encryptedData element with the plaintext XML elemnt.
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;
// Create a new instance of the TrippleDESDocumentEncryption object
// defined in this sample.
TrippleDESDocumentEncryption^ xmlTDES = gcnew TrippleDESDocumentEncryption( xmlDoc,tDESkey );
try
{
// Encrypt the "creditcard" element.
xmlTDES->Encrypt( L"creditcard" );
// Display the encrypted XML to the console.
Console::WriteLine( L"Encrypted XML:" );
Console::WriteLine();
Console::WriteLine( xmlTDES->Doc->OuterXml );
// Decrypt the "creditcard" element.
xmlTDES->Decrypt();
// Display the encrypted XML to the console.
Console::WriteLine();
Console::WriteLine( L"Decrypted XML:" );
Console::WriteLine();
Console::WriteLine( xmlTDES->Doc->OuterXml );
}
catch ( Exception^ e )
{
Console::WriteLine( e->Message );
}
finally
{
// Clear the TripleDES key.
xmlTDES->Clear();
}
return 1;
}
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();
// Create a new instance of the TrippleDESDocumentEncryption object
// defined in this sample.
TrippleDESDocumentEncryption xmlTDES = new TrippleDESDocumentEncryption(xmlDoc, tDESkey);
try
{
// Encrypt the "creditcard" element.
xmlTDES.Encrypt("creditcard");
// Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlTDES.Doc.OuterXml);
// Decrypt the "creditcard" element.
xmlTDES.Decrypt();
// Display the encrypted XML to the console.
Console.WriteLine();
Console.WriteLine("Decrypted XML:");
Console.WriteLine();
Console.WriteLine(xmlTDES.Doc.OuterXml);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear the TripleDES key.
xmlTDES.Clear();
}
}
}
class TrippleDESDocumentEncryption
{
protected XmlDocument docValue;
protected TripleDES algValue;
public TrippleDESDocumentEncryption(XmlDocument Doc, TripleDES Key)
{
if (Doc != null)
{
docValue = Doc;
}
else
{
throw new ArgumentNullException("Doc");
}
if (Key != null)
{
algValue = Key;
}
else
{
throw new ArgumentNullException("Key");
}
}
public XmlDocument Doc { set { docValue = value; } get { return docValue; } }
public TripleDES Alg { set { algValue = value; } get { return algValue; } }
public void Clear()
{
if (algValue != null)
{
algValue.Clear();
}
else
{
throw new Exception("No TripleDES key was found to clear.");
}
}
public void Encrypt(string Element)
{
// Find the element by name and create a new
// XmlElement object.
XmlElement inputElement = docValue.GetElementsByTagName(Element)[0] as XmlElement;
// If the element was not found, throw an exception.
if (inputElement == null)
{
throw new Exception("The element was not found.");
}
// Create a new EncryptedXml object.
EncryptedXml exml = new EncryptedXml(docValue);
// Encrypt the element using the symmetric key.
byte[] rgbOutput = exml.EncryptData(inputElement, algValue, false);
// Create an EncryptedData object and populate it.
EncryptedData ed = new EncryptedData();
// Specify the namespace URI for XML encryption elements.
ed.Type = EncryptedXml.XmlEncElementUrl;
// Specify the namespace URI for the TrippleDES algorithm.
ed.EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncTripleDESUrl);
// Create a CipherData element.
ed.CipherData = new CipherData();
// Set the CipherData element to the value of the encrypted XML element.
ed.CipherData.CipherValue = rgbOutput;
// Replace the plaintext XML elemnt with an EncryptedData element.
EncryptedXml.ReplaceElement(inputElement, ed, false);
}
public void Decrypt()
{
// XmlElement object.
XmlElement encryptedElement = docValue.GetElementsByTagName("EncryptedData")[0] as XmlElement;
// If the EncryptedData element was not found, throw an exception.
if (encryptedElement == null)
{
throw new Exception("The EncryptedData element was not found.");
}
// Create an EncryptedData object and populate it.
EncryptedData ed = new EncryptedData();
ed.LoadXml(encryptedElement);
// Create a new EncryptedXml object.
EncryptedXml exml = new EncryptedXml();
// Decrypt the element using the symmetric key.
byte[] rgbOutput = exml.DecryptData(ed, algValue);
// Replace the encryptedData element with the plaintext XML elemnt.
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.
xmlDoc.PreserveWhitespace = True
xmlDoc.Load("test.xml")
' Create a new TripleDES key.
Dim tDESkey As New TripleDESCryptoServiceProvider()
' Create a new instance of the TrippleDESDocumentEncryption object
' defined in this sample.
Dim xmlTDES As New TrippleDESDocumentEncryption(xmlDoc, tDESkey)
Try
' Encrypt the "creditcard" element.
xmlTDES.Encrypt("creditcard")
' Display the encrypted XML to the console.
Console.WriteLine("Encrypted XML:")
Console.WriteLine()
Console.WriteLine(xmlTDES.Doc.OuterXml)
' Decrypt the "creditcard" element.
xmlTDES.Decrypt()
' Display the encrypted XML to the console.
Console.WriteLine()
Console.WriteLine("Decrypted XML:")
Console.WriteLine()
Console.WriteLine(xmlTDES.Doc.OuterXml)
Catch e As Exception
Console.WriteLine(e.Message)
Finally
' Clear the TripleDES key.
xmlTDES.Clear()
End Try
End Sub
End Module 'Program
Class TrippleDESDocumentEncryption
Protected docValue As XmlDocument
Protected algValue As TripleDES
Public Sub New(ByVal Doc As XmlDocument, ByVal Key As TripleDES)
If Not (Doc Is Nothing) Then
docValue = Doc
Else
Throw New ArgumentNullException("Doc")
End If
If Not (Key Is Nothing) Then
algValue = Key
Else
Throw New ArgumentNullException("Key")
End If
End Sub
Public Property Doc() As XmlDocument
Get
Return docValue
End Get
Set(ByVal value As XmlDocument)
docValue = value
End Set
End Property
Public Property Alg() As TripleDES
Get
Return algValue
End Get
Set(ByVal value As TripleDES)
algValue = value
End Set
End Property
Public Sub Clear()
If Not (algValue Is Nothing) Then
algValue.Clear()
Else
Throw New Exception("No TripleDES key was found to clear.")
End If
End Sub
Public Sub Encrypt(ByVal Element As String)
' Find the element by name and create a new
' XmlElement object.
Dim inputElement As XmlElement = docValue.GetElementsByTagName(Element)(0)
' If the element was not found, throw an exception.
If inputElement Is Nothing Then
Throw New Exception("The element was not found.")
End If
' Create a new EncryptedXml object.
Dim exml As New EncryptedXml(docValue)
' Encrypt the element using the symmetric key.
Dim rgbOutput As Byte() = exml.EncryptData(inputElement, algValue, False)
' Create an EncryptedData object and populate it.
Dim ed As New EncryptedData()
' Specify the namespace URI for XML encryption elements.
ed.Type = EncryptedXml.XmlEncElementUrl
' Specify the namespace URI for the TrippleDES algorithm.
ed.EncryptionMethod = New EncryptionMethod(EncryptedXml.XmlEncTripleDESUrl)
' Create a CipherData element.
ed.CipherData = New CipherData()
' Set the CipherData element to the value of the encrypted XML element.
ed.CipherData.CipherValue = rgbOutput
' Replace the plaintext XML elemnt with an EncryptedData element.
EncryptedXml.ReplaceElement(inputElement, ed, False)
End Sub
Public Sub Decrypt()
' XmlElement object.
Dim encryptedElement As XmlElement = docValue.GetElementsByTagName("EncryptedData")(0)
' If the EncryptedData element was not found, throw an exception.
If encryptedElement Is Nothing Then
Throw New Exception("The EncryptedData element was not found.")
End If
' Create an EncryptedData object and populate it.
Dim ed As New EncryptedData()
ed.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(ed, algValue)
' Replace the encryptedData element with the plaintext XML elemnt.
exml.ReplaceData(encryptedElement, rgbOutput)
End Sub
End Class
The following code example demonstrates how to encrypt an XML document using a symmetric key. This example does not include any key information in the encrypted XML document.
#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
Remarks
The <EncryptionMethod> tag uses a Uniform Resource Identifier (URI) to identify the encryption algorithm that must be used to decrypt XML data. The EncryptionMethod class encapsulates the <EncryptionMethod> tag defined by the World Wide Web Consortium (W3C) XML Encryption Syntax and Processing specification.
Use the EncryptionMethod class to identify the encryption algorithm associated with the EncryptedData element or the EncryptedKey element.
Use one of the URI identifiers defined by the W3C XML Encryption Syntax and Processing specification. All URI identifiers are accessible as static fields of the EncryptedXml class.
Constructors
| EncryptionMethod() |
Initializes a new instance of the EncryptionMethod class. |
| EncryptionMethod(String) |
Initializes a new instance of the EncryptionMethod class specifying an algorithm Uniform Resource Identifier (URI). |
Properties
| KeyAlgorithm |
Gets or sets a Uniform Resource Identifier (URI) that describes the algorithm to use for XML encryption. |
| KeySize |
Gets or sets the algorithm key size used for XML encryption. |
Methods
| Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| GetXml() |
Returns an XmlElement object that encapsulates an instance of the EncryptionMethod class. |
| LoadXml(XmlElement) |
Parses the specified XmlElement object and configures the internal state of the EncryptionMethod object to match. |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
Applies to
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