SignedXml.CheckSignature Method
Definition
Important
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Determines whether the Signature property verifies.
Overloads
| CheckSignature() |
Determines whether the Signature property verifies using the public key in the signature. |
| CheckSignature(AsymmetricAlgorithm) |
Determines whether the Signature property verifies for the specified key. |
| CheckSignature(KeyedHashAlgorithm) |
Determines whether the Signature property verifies for the specified message authentication code (MAC) algorithm. |
| CheckSignature(X509Certificate2, Boolean) |
Determines whether the Signature property verifies for the specified X509Certificate2 object and, optionally, whether the certificate is valid. |
CheckSignature()
- Source:
- SignedXml.cs
- Source:
- SignedXml.cs
Determines whether the Signature property verifies using the public key in the signature.
public:
bool CheckSignature();public bool CheckSignature ();member this.CheckSignature : unit -> boolPublic Function CheckSignature () As BooleanReturns
true if the Signature property verifies; otherwise, false.
Exceptions
The SignatureAlgorithm property of the public key in the signature does not match the SignatureMethod property.
-or-
The signature description could not be created.
-or
The hash algorithm could not be created.
Examples
The following code example shows how to sign and verify an entire XML document using an enveloped signature.
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Security.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
void SignXmlFile( String^ FileName, String^ SignedFileName, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Load the passed XML file using its name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Add the key to the SignedXml document.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform^ env = gcnew XmlDsigEnvelopedSignatureTransform;
reference->AddTransform( env );
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
if ( (doc->FirstChild)->GetType() == XmlDeclaration::typeid )
{
doc->RemoveChild( doc->FirstChild );
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
Boolean VerifyXmlFile( String^ Name, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( safe_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature( Key );
}
// Create example data to sign.
void CreateSomeXml( String^ FileName )
{
// Create a new XmlDocument Object*.
XmlDocument^ document = gcnew XmlDocument;
// Create a new XmlNode object.
XmlNode^ node = document->CreateNode( XmlNodeType::Element, "", "MyElement", "samples" );
// Add some text to the node.
node->InnerText = "Example text to be signed.";
// Append the node to the document.
document->AppendChild( node );
// Save the XML document to the file name specified.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( FileName,gcnew UTF8Encoding( false ) );
document->WriteTo( xmltw );
xmltw->Close();
}
int main()
{
try
{
// Generate a signing key.
RSA^ Key = RSA::Create();
// Create an XML file to sign.
CreateSomeXml( "Example.xml" );
Console::WriteLine( "New XML file created." );
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile( "Example.xml", "signedExample.xml", Key );
Console::WriteLine( "XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying signature..." );
bool result = VerifyXmlFile( "SignedExample.xml", Key );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
try
{
// Generate a signing key.
RSA Key = RSA.Create();
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "signedExample.xml", Key);
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
bool result = VerifyXmlFile("SignedExample.xml", Key);
// Display the results of the signature verification to
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
public static void SignXmlFile(string FileName, string SignedFileName, RSA Key)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Load the passed XML file using its name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
public static Boolean VerifyXmlFile(String Name, RSA Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature(Key);
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples");
// Add some text to the node.
node.InnerText = "Example text to be signed.";
// Append the node to the document.
document.AppendChild(node);
// Save the XML document to the file name specified.
XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
document.WriteTo(xmltw);
xmltw.Close();
}
}
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Public Class SignVerifyEnvelope
Overloads Public Shared Sub Main(args() As [String])
Try
' Generate a signing key.
Dim Key As RSA = RSA.Create()
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "signedExample.xml", Key)
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml", Key)
' Display the results of the signature verification to
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file. This method does not
' save the public key within the XML file. This file cannot be verified unless
' the verifying code has the key with which it was signed.
Public Shared Sub SignXmlFile(FileName As String, SignedFileName As String, Key As RSA)
' Create a new XML document.
Dim doc As New XmlDocument()
' Load the passed XML file using its name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Add an enveloped transformation to the reference.
Dim env As New XmlDsigEnvelopedSignatureTransform()
reference.AddTransform(env)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
If TypeOf doc.FirstChild Is XmlDeclaration Then
doc.RemoveChild(doc.FirstChild)
End If
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file against an asymmetric
' algorithm and return the result.
Public Shared Function VerifyXmlFile(Name As [String], Key As RSA) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature(Key)
End Function
' Create example data to sign.
Public Shared Sub CreateSomeXml(FileName As String)
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples")
' Add some text to the node.
node.InnerText = "Example text to be signed."
' Append the node to the document.
document.AppendChild(node)
' Save the XML document to the file name specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
document.WriteTo(xmltw)
xmltw.Close()
End Sub
End Class
The following code example shows how to sign and verify a Uniform Resource Identifier (URI) addressable object using a detached signature.
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
#using <System.dll>
#using <System.Xml.dll>
#using <System.Security.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
void SignDetachedResource( String^ URIString, String^ XmlSigFileName, RSA^ Key )
{
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml;
// Assign the key to the SignedXml object.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
// Add the passed URI to the reference object.
reference->Uri = URIString;
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( XmlSigFileName,gcnew UTF8Encoding( false ) );
xmlDigitalSignature->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
static Boolean VerifyDetachedSignature( String^ XmlSigFileName, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Load the passedXML file into the document.
xmlDocument->Load( XmlSigFileName );
// Create a new SignedXml object.
SignedXml^ signedXml = gcnew SignedXml;
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( dynamic_cast<XmlElement^>(nodeList[ 0 ]) );
// Check the signature against the passed asymmetric key
// and return the result.
return signedXml->CheckSignature( Key );
}
int main()
{
// The URI to sign.
String^ resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
String^ XmlFileName = "xmldsig.xml";
try
{
// Generate a signing key.
RSA^ Key = RSA::Create();
Console::WriteLine( "Signing: {0}", resourceToSign );
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource( resourceToSign, XmlFileName, Key );
Console::WriteLine( "XML Signature was successfully computed and saved to {0}.", XmlFileName );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying signature..." );
//Verify the XML signature in the XML file against the key.
bool result = VerifyDetachedSignature( XmlFileName, Key );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
}
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
class XMLDSIGDetached
{
[STAThread]
static void Main(string[] args)
{
// The URI to sign.
string resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
string XmlFileName = "xmldsig.xml";
try
{
// Generate a signing key.
RSA Key = RSA.Create();
Console.WriteLine("Signing: {0}", resourceToSign);
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key);
Console.WriteLine("XML Signature was successfully computed and saved to {0}.", XmlFileName);
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
//Verify the XML signature in the XML file against the key.
bool result = VerifyDetachedSignature(XmlFileName, Key);
// Display the results of the signature verification to
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
public static void SignDetachedResource(string URIString, string XmlSigFileName, RSA Key)
{
// Create a SignedXml object.
SignedXml signedXml = new SignedXml();
// Assign the key to the SignedXml object.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
// Add the passed URI to the reference object.
reference.Uri = URIString;
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(XmlSigFileName, new UTF8Encoding(false));
xmlDigitalSignature.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
public static Boolean VerifyDetachedSignature(string XmlSigFileName, RSA Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName);
// Create a new SignedXml object.
SignedXml signedXml = new SignedXml();
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature against the passed asymmetric key
// and return the result.
return signedXml.CheckSignature(Key);
}
}
'
' This example signs a file specified by a URI
' using a detached signature. It then verifies
' the signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Class XMLDSIGDetached
<STAThread()> _
Overloads Shared Sub Main(args() As String)
' The URI to sign.
Dim resourceToSign As String = "http://www.microsoft.com"
' The name of the file to which to save the XML signature.
Dim XmlFileName As String = "xmldsig.xml"
Try
' Generate a signing key.
Dim Key As RSA = RSA.Create()
Console.WriteLine("Signing: {0}", resourceToSign)
' Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key)
Console.WriteLine("XML Signature was successfully computed and saved to {0}.", XmlFileName)
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
'Verify the XML signature in the XML file against the key.
Dim result As Boolean = VerifyDetachedSignature(XmlFileName, Key)
' Display the results of the signature verification to
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file. This method does not
' save the public key within the XML file. This file cannot be verified unless
' the verifying code has the key with which it was signed.
Public Shared Sub SignDetachedResource(URIString As String, XmlSigFileName As String, Key As RSA)
' Create a SignedXml object.
Dim signedXml As New SignedXml()
' Assign the key to the SignedXml object.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
' Add the passed URI to the reference object.
reference.Uri = URIString
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(XmlSigFileName, New UTF8Encoding(False))
xmlDigitalSignature.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file against an asymmetric
' algorithm and return the result.
Public Shared Function VerifyDetachedSignature(XmlSigFileName As String, Key As RSA) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName)
' Create a new SignedXml object.
Dim signedXml As New SignedXml()
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature against the passed asymmetric key
' and return the result.
Return signedXml.CheckSignature(Key)
End Function
End Class
The following code example shows how to sign and verify a single element of an XML document using an enveloping signature.
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Xml.dll>
#using <System.Security.dll>
#using <System.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file.
static void SignXmlFile( String^ FileName, String^ SignedFileName, RSA^ Key, array<String^>^ElementsToSign )
{
// Check the arguments.
if ( FileName == nullptr )
throw gcnew ArgumentNullException( L"FileName" );
if ( SignedFileName == nullptr )
throw gcnew ArgumentNullException( L"SignedFileName" );
if ( Key == nullptr )
throw gcnew ArgumentNullException( L"Key" );
if ( ElementsToSign == nullptr )
throw gcnew ArgumentNullException( L"ElementsToSign" );
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Format the document to ignore white spaces.
doc->PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Add the key to the SignedXml document.
signedXml->SigningKey = Key;
// Loop through each passed element to sign
// and create a reference.
System::Collections::IEnumerator^ myEnum = ElementsToSign->GetEnumerator();
while ( myEnum->MoveNext() )
{
String^ s = safe_cast<String^>(myEnum->Current);
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = s;
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform^ env = gcnew XmlDsigEnvelopedSignatureTransform;
reference->AddTransform( env );
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
}
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo^ keyInfo = gcnew KeyInfo;
keyInfo->AddClause( gcnew RSAKeyValue( dynamic_cast<RSA^>(Key) ) );
signedXml->KeyInfo = keyInfo;
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
if ( dynamic_cast<XmlDeclaration^>(doc->FirstChild) )
{
doc->RemoveChild( doc->FirstChild );
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file and return the result.
static Boolean VerifyXmlFile( String^ Name )
{
// Check the arguments.
if ( Name == nullptr )
throw gcnew ArgumentNullException( L"Name" );
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Format using white spaces.
xmlDocument->PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( L"Signature" );
// Load the signature node.
signedXml->LoadXml( dynamic_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature();
}
int main()
{
// Generate a signing key.
RSA^ Key = RSA::Create();
try
{
// Specify an element to sign.
array<String^>^elements = {L"#tag1"};
// Sign an XML file and save the signature to a
// new file.
SignXmlFile( L"Test.xml", L"SignedExample.xml", Key, elements );
Console::WriteLine( L"XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( L"Verifying signature..." );
bool result = VerifyXmlFile( L"SignedExample.xml" );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( L"The XML signature is valid." );
}
else
{
Console::WriteLine( L"The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
finally
{
// Clear resources associated with the
// RSA instance.
Key->Clear();
}
return 1;
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
// Generate a signing key.
RSA Key = RSA.Create();
try
{
// Specify an element to sign.
string[] elements = { "#tag1" };
// Sign an XML file and save the signature to a
// new file.
SignXmlFile("Test.xml", "SignedExample.xml", Key, elements);
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
bool result = VerifyXmlFile("SignedExample.xml");
// Display the results of the signature verification to
// the console.
if (result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch (CryptographicException e)
{
Console.WriteLine(e.Message);
}
finally
{
// Clear resources associated with the
// RSA instance.
Key.Clear();
}
}
// Sign an XML file and save the signature in a new file.
public static void SignXmlFile(string FileName, string SignedFileName, RSA Key, string[] ElementsToSign)
{
// Check the arguments.
if (FileName == null)
throw new ArgumentNullException("FileName");
if (SignedFileName == null)
throw new ArgumentNullException("SignedFileName");
if (Key == null)
throw new ArgumentNullException("Key");
if (ElementsToSign == null)
throw new ArgumentNullException("ElementsToSign");
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Format the document to ignore white spaces.
doc.PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = Key;
// Loop through each passed element to sign
// and create a reference.
foreach (string s in ElementsToSign)
{
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = s;
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
}
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo keyInfo = new KeyInfo();
keyInfo.AddClause(new RSAKeyValue((RSA)Key));
signedXml.KeyInfo = keyInfo;
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file and return the result.
public static Boolean VerifyXmlFile(String Name)
{
// Check the arguments.
if (Name == null)
throw new ArgumentNullException("Name");
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Format using white spaces.
xmlDocument.PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature();
}
}
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Module SignVerifyEnvelope
Sub Main(ByVal args() As String)
' Generate a signing key.
Dim Key As RSA = RSA.Create()
Try
' Specify an element to sign.
Dim elements As String() = New String() {"#tag1"}
' Sign an XML file and save the signature to a
' new file.
SignXmlFile("Test.xml", "SignedExample.xml", Key, elements)
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml")
' Display the results of the signature verification to \
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
Finally
' Clear resources associated with the
' RSA instance.
Key.Clear()
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Sub SignXmlFile(ByVal FileName As String, ByVal SignedFileName As String, ByVal Key As RSA, ByVal ElementsToSign() As String)
' Check the arguments.
If FileName Is Nothing Then
Throw New ArgumentNullException("FileName")
End If
If SignedFileName Is Nothing Then
Throw New ArgumentNullException("SignedFileName")
End If
If Key Is Nothing Then
Throw New ArgumentNullException("Key")
End If
If ElementsToSign Is Nothing Then
Throw New ArgumentNullException("ElementsToSign")
End If
' Create a new XML document.
Dim doc As New XmlDocument()
' Format the document to ignore white spaces.
doc.PreserveWhitespace = False
' Load the passed XML file using it's name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = Key
' Loop through each passed element to sign
' and create a reference.
Dim s As String
For Each s In ElementsToSign
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = s
' Add an enveloped transformation to the reference.
Dim env As New XmlDsigEnvelopedSignatureTransform()
reference.AddTransform(env)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
Next s
' Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
Dim keyInfo As New KeyInfo()
keyInfo.AddClause(New RSAKeyValue(CType(Key, RSA)))
signedXml.KeyInfo = keyInfo
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
If TypeOf doc.FirstChild Is XmlDeclaration Then
doc.RemoveChild(doc.FirstChild)
End If
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file and return the result.
Function VerifyXmlFile(ByVal Name As String) As [Boolean]
' Check the arguments.
If Name Is Nothing Then
Throw New ArgumentNullException("Name")
End If
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Format using white spaces.
xmlDocument.PreserveWhitespace = True
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature()
End Function
End Module
Remarks
This method also computes the digest of the references and the value of the signature.
If an XML document was signed with an X.509 signature, the CheckSignature method will search the "AddressBook" store for certificates suitable for the verification. For example, if the certificate is referenced by a Subject Key Identifier (SKI), the CheckSignature method will select certificates with this SKI and try them one after another until it can verify the certificate.
Applies to
CheckSignature(AsymmetricAlgorithm)
- Source:
- SignedXml.cs
- Source:
- SignedXml.cs
Determines whether the Signature property verifies for the specified key.
public:
bool CheckSignature(System::Security::Cryptography::AsymmetricAlgorithm ^ key);public bool CheckSignature (System.Security.Cryptography.AsymmetricAlgorithm key);member this.CheckSignature : System.Security.Cryptography.AsymmetricAlgorithm -> boolPublic Function CheckSignature (key As AsymmetricAlgorithm) As BooleanParameters
The implementation of the AsymmetricAlgorithm property that holds the key to be used to verify the Signature property.
Returns
true if the Signature property verifies for the specified key; otherwise, false.
Exceptions
The key parameter is null.
The SignatureAlgorithm property of the key parameter does not match the SignatureMethod property.
-or-
The signature description could not be created.
-or
The hash algorithm could not be created.
Examples
The following code example shows how to sign and verify a Uniform Resource Identifier (URI) addressable object using a detached signature.
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
#using <System.dll>
#using <System.Xml.dll>
#using <System.Security.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
void SignDetachedResource( String^ URIString, String^ XmlSigFileName, RSA^ Key )
{
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml;
// Assign the key to the SignedXml object.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
// Add the passed URI to the reference object.
reference->Uri = URIString;
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( XmlSigFileName,gcnew UTF8Encoding( false ) );
xmlDigitalSignature->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
static Boolean VerifyDetachedSignature( String^ XmlSigFileName, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Load the passedXML file into the document.
xmlDocument->Load( XmlSigFileName );
// Create a new SignedXml object.
SignedXml^ signedXml = gcnew SignedXml;
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( dynamic_cast<XmlElement^>(nodeList[ 0 ]) );
// Check the signature against the passed asymmetric key
// and return the result.
return signedXml->CheckSignature( Key );
}
int main()
{
// The URI to sign.
String^ resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
String^ XmlFileName = "xmldsig.xml";
try
{
// Generate a signing key.
RSA^ Key = RSA::Create();
Console::WriteLine( "Signing: {0}", resourceToSign );
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource( resourceToSign, XmlFileName, Key );
Console::WriteLine( "XML Signature was successfully computed and saved to {0}.", XmlFileName );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying signature..." );
//Verify the XML signature in the XML file against the key.
bool result = VerifyDetachedSignature( XmlFileName, Key );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
}
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
class XMLDSIGDetached
{
[STAThread]
static void Main(string[] args)
{
// The URI to sign.
string resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
string XmlFileName = "xmldsig.xml";
try
{
// Generate a signing key.
RSA Key = RSA.Create();
Console.WriteLine("Signing: {0}", resourceToSign);
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key);
Console.WriteLine("XML Signature was successfully computed and saved to {0}.", XmlFileName);
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
//Verify the XML signature in the XML file against the key.
bool result = VerifyDetachedSignature(XmlFileName, Key);
// Display the results of the signature verification to
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
public static void SignDetachedResource(string URIString, string XmlSigFileName, RSA Key)
{
// Create a SignedXml object.
SignedXml signedXml = new SignedXml();
// Assign the key to the SignedXml object.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
// Add the passed URI to the reference object.
reference.Uri = URIString;
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(XmlSigFileName, new UTF8Encoding(false));
xmlDigitalSignature.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
public static Boolean VerifyDetachedSignature(string XmlSigFileName, RSA Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName);
// Create a new SignedXml object.
SignedXml signedXml = new SignedXml();
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature against the passed asymmetric key
// and return the result.
return signedXml.CheckSignature(Key);
}
}
'
' This example signs a file specified by a URI
' using a detached signature. It then verifies
' the signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Class XMLDSIGDetached
<STAThread()> _
Overloads Shared Sub Main(args() As String)
' The URI to sign.
Dim resourceToSign As String = "http://www.microsoft.com"
' The name of the file to which to save the XML signature.
Dim XmlFileName As String = "xmldsig.xml"
Try
' Generate a signing key.
Dim Key As RSA = RSA.Create()
Console.WriteLine("Signing: {0}", resourceToSign)
' Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key)
Console.WriteLine("XML Signature was successfully computed and saved to {0}.", XmlFileName)
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
'Verify the XML signature in the XML file against the key.
Dim result As Boolean = VerifyDetachedSignature(XmlFileName, Key)
' Display the results of the signature verification to
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file. This method does not
' save the public key within the XML file. This file cannot be verified unless
' the verifying code has the key with which it was signed.
Public Shared Sub SignDetachedResource(URIString As String, XmlSigFileName As String, Key As RSA)
' Create a SignedXml object.
Dim signedXml As New SignedXml()
' Assign the key to the SignedXml object.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
' Add the passed URI to the reference object.
reference.Uri = URIString
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(XmlSigFileName, New UTF8Encoding(False))
xmlDigitalSignature.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file against an asymmetric
' algorithm and return the result.
Public Shared Function VerifyDetachedSignature(XmlSigFileName As String, Key As RSA) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName)
' Create a new SignedXml object.
Dim signedXml As New SignedXml()
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature against the passed asymmetric key
' and return the result.
Return signedXml.CheckSignature(Key)
End Function
End Class
The following code example shows how to sign and verify an entire XML document using an enveloped signature.
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Security.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
void SignXmlFile( String^ FileName, String^ SignedFileName, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Load the passed XML file using its name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Add the key to the SignedXml document.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform^ env = gcnew XmlDsigEnvelopedSignatureTransform;
reference->AddTransform( env );
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
if ( (doc->FirstChild)->GetType() == XmlDeclaration::typeid )
{
doc->RemoveChild( doc->FirstChild );
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
Boolean VerifyXmlFile( String^ Name, RSA^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( safe_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature( Key );
}
// Create example data to sign.
void CreateSomeXml( String^ FileName )
{
// Create a new XmlDocument Object*.
XmlDocument^ document = gcnew XmlDocument;
// Create a new XmlNode object.
XmlNode^ node = document->CreateNode( XmlNodeType::Element, "", "MyElement", "samples" );
// Add some text to the node.
node->InnerText = "Example text to be signed.";
// Append the node to the document.
document->AppendChild( node );
// Save the XML document to the file name specified.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( FileName,gcnew UTF8Encoding( false ) );
document->WriteTo( xmltw );
xmltw->Close();
}
int main()
{
try
{
// Generate a signing key.
RSA^ Key = RSA::Create();
// Create an XML file to sign.
CreateSomeXml( "Example.xml" );
Console::WriteLine( "New XML file created." );
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile( "Example.xml", "signedExample.xml", Key );
Console::WriteLine( "XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying signature..." );
bool result = VerifyXmlFile( "SignedExample.xml", Key );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
try
{
// Generate a signing key.
RSA Key = RSA.Create();
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "signedExample.xml", Key);
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
bool result = VerifyXmlFile("SignedExample.xml", Key);
// Display the results of the signature verification to
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file. This method does not
// save the public key within the XML file. This file cannot be verified unless
// the verifying code has the key with which it was signed.
public static void SignXmlFile(string FileName, string SignedFileName, RSA Key)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Load the passed XML file using its name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
public static Boolean VerifyXmlFile(String Name, RSA Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature(Key);
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples");
// Add some text to the node.
node.InnerText = "Example text to be signed.";
// Append the node to the document.
document.AppendChild(node);
// Save the XML document to the file name specified.
XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
document.WriteTo(xmltw);
xmltw.Close();
}
}
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Public Class SignVerifyEnvelope
Overloads Public Shared Sub Main(args() As [String])
Try
' Generate a signing key.
Dim Key As RSA = RSA.Create()
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "signedExample.xml", Key)
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml", Key)
' Display the results of the signature verification to
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file. This method does not
' save the public key within the XML file. This file cannot be verified unless
' the verifying code has the key with which it was signed.
Public Shared Sub SignXmlFile(FileName As String, SignedFileName As String, Key As RSA)
' Create a new XML document.
Dim doc As New XmlDocument()
' Load the passed XML file using its name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Add an enveloped transformation to the reference.
Dim env As New XmlDsigEnvelopedSignatureTransform()
reference.AddTransform(env)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
If TypeOf doc.FirstChild Is XmlDeclaration Then
doc.RemoveChild(doc.FirstChild)
End If
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file against an asymmetric
' algorithm and return the result.
Public Shared Function VerifyXmlFile(Name As [String], Key As RSA) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature(Key)
End Function
' Create example data to sign.
Public Shared Sub CreateSomeXml(FileName As String)
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples")
' Add some text to the node.
node.InnerText = "Example text to be signed."
' Append the node to the document.
document.AppendChild(node)
' Save the XML document to the file name specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
document.WriteTo(xmltw)
xmltw.Close()
End Sub
End Class
Applies to
CheckSignature(KeyedHashAlgorithm)
- Source:
- SignedXml.cs
- Source:
- SignedXml.cs
Determines whether the Signature property verifies for the specified message authentication code (MAC) algorithm.
public:
bool CheckSignature(System::Security::Cryptography::KeyedHashAlgorithm ^ macAlg);public bool CheckSignature (System.Security.Cryptography.KeyedHashAlgorithm macAlg);member this.CheckSignature : System.Security.Cryptography.KeyedHashAlgorithm -> boolPublic Function CheckSignature (macAlg As KeyedHashAlgorithm) As BooleanParameters
- macAlg
- KeyedHashAlgorithm
The implementation of KeyedHashAlgorithm that holds the MAC to be used to verify the Signature property.
Returns
true if the Signature property verifies for the specified MAC; otherwise, false.
Exceptions
The macAlg parameter is null.
The HashSize property of the specified KeyedHashAlgorithm object is not valid.
-or-
The Signature property is null.
-or-
The cryptographic transform used to check the signature could not be created.
Examples
The following code example shows how to sign and verify a Uniform Resource Identifier (URI) addressable object using a detached signature.
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
#using <System.Security.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file.
void SignDetachedResource( String^ URIString, String^ XmlSigFileName, KeyedHashAlgorithm^ Key )
{
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
// Add the passed URI to the reference object.
reference->Uri = URIString;
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature( Key );
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( XmlSigFileName,gcnew UTF8Encoding( false ) );
xmlDigitalSignature->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file and return the result.
Boolean VerifyDetachedSignature( String^ XmlSigFileName, KeyedHashAlgorithm^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Load the passedXML file into the document.
xmlDocument->Load( XmlSigFileName );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml;
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( safe_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature( Key );
}
int main()
{
try
{
// The URI to sign.
String^ resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
String^ XmlFileName = "xmlsig.xml";
// Generate a signing key.
HMACSHA256^ Key = gcnew HMACSHA256;
Console::WriteLine( "Signing: {0}", resourceToSign );
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource( resourceToSign, XmlFileName, Key );
Console::WriteLine( "XML signature was successfully computed and saved to {0}.", XmlFileName );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying signature..." );
//Verify the XML signature in the XML file.
bool result = VerifyDetachedSignature( XmlFileName, Key );
// Display the results of the signature verification to
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
}
//
// This example signs a file specified by a URI
// using a detached signature. It then verifies
// the signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
class XMLDSIGDetached
{
[STAThread]
static void Main(string[] args)
{
try
{
// The URI to sign.
string resourceToSign = "http://www.microsoft.com";
// The name of the file to which to save the XML signature.
string XmlFileName = "xmlsig.xml";
// Generate a signing key.
HMACSHA256 Key = new HMACSHA256();
Console.WriteLine("Signing: {0}", resourceToSign);
// Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key);
Console.WriteLine("XML signature was successfully computed and saved to {0}.", XmlFileName);
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
//Verify the XML signature in the XML file.
bool result = VerifyDetachedSignature(XmlFileName, Key);
// Display the results of the signature verification to
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file.
public static void SignDetachedResource(string URIString, string XmlSigFileName, KeyedHashAlgorithm Key)
{
// Create a SignedXml object.
SignedXml signedXml = new SignedXml();
// Create a reference to be signed.
Reference reference = new Reference();
// Add the passed URI to the reference object.
reference.Uri = URIString;
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature(Key);
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(XmlSigFileName, new UTF8Encoding(false));
xmlDigitalSignature.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file and return the result.
public static Boolean VerifyDetachedSignature(string XmlSigFileName, KeyedHashAlgorithm Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml();
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature(Key);
}
}
'
' This example signs a file specified by a URI
' using a detached signature. It then verifies
' the signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Class XMLDSIGDetached
<STAThread()> _
Overloads Shared Sub Main(args() As String)
Try
' The URI to sign.
Dim resourceToSign As String = "http://www.microsoft.com"
' The name of the file to which to save the XML signature.
Dim XmlFileName As String = "xmlsig.xml"
' Generate a signing key.
Dim Key As New HMACSHA256()
Console.WriteLine("Signing: {0}", resourceToSign)
' Sign the detached resourceand save the signature in an XML file.
SignDetachedResource(resourceToSign, XmlFileName, Key)
Console.WriteLine("XML signature was successfully computed and saved to {0}.", XmlFileName)
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
'Verify the XML signature in the XML file.
Dim result As Boolean = VerifyDetachedSignature(XmlFileName, Key)
' Display the results of the signature verification to
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Public Shared Sub SignDetachedResource(URIString As String, XmlSigFileName As String, Key As KeyedHashAlgorithm)
' Create a SignedXml object.
Dim signedXml As New SignedXml()
' Create a reference to be signed.
Dim reference As New Reference()
' Add the passed URI to the reference object.
reference.Uri = URIString
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature(Key)
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(XmlSigFileName, New UTF8Encoding(False))
xmlDigitalSignature.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file and return the result.
Public Shared Function VerifyDetachedSignature(XmlSigFileName As String, Key As KeyedHashAlgorithm) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passedXML file into the document.
xmlDocument.Load(XmlSigFileName)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml()
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature(Key)
End Function
End Class
The following code example shows how to sign and verify an entire XML document using an enveloping signature.
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Security.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Sign an XML file and save the signature in a new file.
void SignXmlFile( String^ FileName, String^ SignedFileName, KeyedHashAlgorithm^ Key )
{
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Format the document to ignore white spaces.
doc->PreserveWhitespace = false;
// Load the passed XML file using its name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform^ env = gcnew XmlDsigEnvelopedSignatureTransform;
reference->AddTransform( env );
// Add the reference to the SignedXML object.
signedXml->AddReference( reference );
// Compute the signature.
signedXml->ComputeSignature( Key );
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
if ( (doc->FirstChild)->GetType() == XmlDeclaration::typeid )
{
doc->RemoveChild( doc->FirstChild );
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file and return the result.
Boolean VerifyXmlFile( String^ Name, KeyedHashAlgorithm^ Key )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Format using white spaces.
xmlDocument->PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXMl object and pass it
// the XMl document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( "Signature" );
// Load the signature node.
signedXml->LoadXml( safe_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature( Key );
}
// Create example data to sign.
void CreateSomeXml( String^ FileName )
{
// Create a new XmlDocument object.
XmlDocument^ document = gcnew XmlDocument;
// Create a new XmlNode object.
XmlNode^ node = document->CreateNode( XmlNodeType::Element, "", "MyElement", "samples" );
// Add some text to the node.
node->InnerText = "Example text to be signed.";
// Append the node to the document.
document->AppendChild( node );
// Save the XML document to the filename specified.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( FileName,gcnew UTF8Encoding( false ) );
document->WriteTo( xmltw );
xmltw->Close();
}
int main()
{
try
{
// Generate a signing key.
HMACSHA256^ Key = gcnew HMACSHA256;
// Create an XML file to sign.
CreateSomeXml( "Example.xml" );
Console::WriteLine( "New XML file created." );
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile( "Example.xml", "SignedExample.xml", Key );
Console::WriteLine( "XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( "Verifying Signature..." );
bool result = VerifyXmlFile( "SignedExample.xml", Key );
// Display the results of the signature verification to \
// the console.
if ( result )
{
Console::WriteLine( "The XML signature is valid." );
}
else
{
Console::WriteLine( "The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
return 0;
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
try
{
// Generate a signing key.
HMACSHA256 Key = new HMACSHA256();
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key);
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying Signature...");
bool result = VerifyXmlFile("SignedExample.xml", Key);
// Display the results of the signature verification to \
// the console.
if(result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch(CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file.
public static void SignXmlFile(string FileName, string SignedFileName, KeyedHashAlgorithm Key)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Format the document to ignore white spaces.
doc.PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXML object.
signedXml.AddReference(reference);
// Compute the signature.
signedXml.ComputeSignature(Key);
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file and return the result.
public static Boolean VerifyXmlFile(String Name, KeyedHashAlgorithm Key)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Format using white spaces.
xmlDocument.PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXMl object and pass it
// the XMl document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature(Key);
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples");
// Add some text to the node.
node.InnerText = "Example text to be signed.";
// Append the node to the document.
document.AppendChild(node);
// Save the XML document to the filename specified.
XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
document.WriteTo(xmltw);
xmltw.Close();
}
}
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Public Class SignVerifyEnvelope
Overloads Public Shared Sub Main(args() As [String])
Try
' Generate a signing key.
Dim Key As New HMACSHA256()
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key)
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying Signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml", Key)
' Display the results of the signature verification to \
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Public Shared Sub SignXmlFile(FileName As String, SignedFileName As String, Key As KeyedHashAlgorithm)
' Create a new XML document.
Dim doc As New XmlDocument()
' Format the document to ignore white spaces.
doc.PreserveWhitespace = False
' Load the passed XML file using it's name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Add an enveloped transformation to the reference.
Dim env As New XmlDsigEnvelopedSignatureTransform()
reference.AddTransform(env)
' Add the reference to the SignedXML object.
signedXml.AddReference(reference)
' Compute the signature.
signedXml.ComputeSignature(Key)
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
If TypeOf doc.FirstChild Is XmlDeclaration Then
doc.RemoveChild(doc.FirstChild)
End If
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file and return the result.
Public Shared Function VerifyXmlFile(Name As [String], Key As KeyedHashAlgorithm) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Format using white spaces.
xmlDocument.PreserveWhitespace = True
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXMl object and pass it
' the XMl document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature(Key)
End Function
' Create example data to sign.
Public Shared Sub CreateSomeXml(FileName As String)
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples")
' Add some text to the node.
node.InnerText = "Example text to be signed."
' Append the node to the document.
document.AppendChild(node)
' Save the XML document to the filename specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
document.WriteTo(xmltw)
xmltw.Close()
End Sub
End Class
Applies to
CheckSignature(X509Certificate2, Boolean)
- Source:
- SignedXml.cs
- Source:
- SignedXml.cs
Determines whether the Signature property verifies for the specified X509Certificate2 object and, optionally, whether the certificate is valid.
public:
bool CheckSignature(System::Security::Cryptography::X509Certificates::X509Certificate2 ^ certificate, bool verifySignatureOnly);public bool CheckSignature (System.Security.Cryptography.X509Certificates.X509Certificate2 certificate, bool verifySignatureOnly);[System.Runtime.InteropServices.ComVisible(false)]
public bool CheckSignature (System.Security.Cryptography.X509Certificates.X509Certificate2 certificate, bool verifySignatureOnly);member this.CheckSignature : System.Security.Cryptography.X509Certificates.X509Certificate2 * bool -> bool[<System.Runtime.InteropServices.ComVisible(false)>]
member this.CheckSignature : System.Security.Cryptography.X509Certificates.X509Certificate2 * bool -> boolPublic Function CheckSignature (certificate As X509Certificate2, verifySignatureOnly As Boolean) As BooleanParameters
- certificate
- X509Certificate2
The X509Certificate2 object to use to verify the Signature property.
- verifySignatureOnly
- Boolean
true to verify the signature only; false to verify both the signature and certificate.
Returns
true if the signature is valid; otherwise, false.
-or-
true if the signature and certificate are valid; otherwise, false.
- Attributes
Exceptions
The certificate parameter is null.
A signature description could not be created for the certificate parameter.
Examples
The following code example uses an X.509 certificate from a certificate store to sign and verify an XML document.
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
// You must have a certificate with a subject name
// of "CN=XMLDSIG_Test" in the "My" certificate store.
//
// Run the following command to create a certificate
// and place it in the store.
// makecert -r -pe -n "CN=XMLDSIG_Test" -b 01/01/2005 -e 01/01/2010 -sky signing -ss my
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
string Certificate = "CN=XMLDSIG_Test";
try
{
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "SignedExample.xml", Certificate);
Console.WriteLine("XML file signed.");
if (VerifyXmlFile("SignedExample.xml", Certificate))
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch (CryptographicException e)
{
Console.WriteLine(e.Message);
}
}
// Sign an XML file and save the signature in a new file.
public static void SignXmlFile(string FileName, string SignedFileName, string SubjectName)
{
if (null == FileName)
throw new ArgumentNullException("FileName");
if (null == SignedFileName)
throw new ArgumentNullException("SignedFileName");
if (null == SubjectName)
throw new ArgumentNullException("SubjectName");
// Load the certificate from the certificate store.
X509Certificate2 cert = GetCertificateBySubject(SubjectName);
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Format the document to ignore white spaces.
doc.PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = cert.GetRSAPrivateKey();
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Add an enveloped transformation to the reference.
XmlDsigEnvelopedSignatureTransform env = new XmlDsigEnvelopedSignatureTransform();
reference.AddTransform(env);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Create a new KeyInfo object.
KeyInfo keyInfo = new KeyInfo();
// Load the certificate into a KeyInfoX509Data object
// and add it to the KeyInfo object.
keyInfo.AddClause(new KeyInfoX509Data(cert));
// Add the KeyInfo object to the SignedXml object.
signedXml.KeyInfo = keyInfo;
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
if (doc.FirstChild is XmlDeclaration)
{
doc.RemoveChild(doc.FirstChild);
}
// Save the signed XML document to a file specified
// using the passed string.
using (XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false)))
{
doc.WriteTo(xmltw);
xmltw.Close();
}
}
// Verify the signature of an XML file against an asymmetric
// algorithm and return the result.
public static Boolean VerifyXmlFile(String FileName, String CertificateSubject)
{
// Check the args.
if (null == FileName)
throw new ArgumentNullException("FileName");
if (null == CertificateSubject)
throw new ArgumentNullException("CertificateSubject");
// Load the certificate from the store.
X509Certificate2 cert = GetCertificateBySubject(CertificateSubject);
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Load the passed XML file into the document.
xmlDocument.Load(FileName);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature(cert, true);
}
public static X509Certificate2 GetCertificateBySubject(string CertificateSubject)
{
// Check the args.
if (null == CertificateSubject)
throw new ArgumentNullException("CertificateSubject");
// Load the certificate from the certificate store.
X509Certificate2 cert = null;
X509Store store = new X509Store("My", StoreLocation.CurrentUser);
try
{
// Open the store.
store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
// Get the certs from the store.
X509Certificate2Collection CertCol = store.Certificates;
// Find the certificate with the specified subject.
foreach (X509Certificate2 c in CertCol)
{
if (c.Subject == CertificateSubject)
{
cert = c;
break;
}
}
// Throw an exception of the certificate was not found.
if (cert == null)
{
throw new CryptographicException("The certificate could not be found.");
}
}
finally
{
// Close the store even if an exception was thrown.
store.Close();
}
return cert;
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Check the args.
if (null == FileName)
throw new ArgumentNullException("FileName");
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples");
// Add some text to the node.
node.InnerText = "Example text to be signed.";
// Append the node to the document.
document.AppendChild(node);
// Save the XML document to the file name specified.
using (XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false)))
{
document.WriteTo(xmltw);
xmltw.Close();
}
}
}
// This code example displays the following to the console:
//
// New XML file created.
// XML file signed.
// The XML signature is valid.
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
' You must have a certificate with a subject name
' of "CN=XMLDSIG_Test" in the "My" certificate store.
'
' Run the following command to create a certificate
' and place it in the store.
' makecert -r -pe -n "CN=XMLDSIG_Test" -b 01/01/2005 -e 01/01/2010 -sky signing -ss my
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Imports System.Security.Cryptography.X509Certificates
Imports System.Text
Imports System.Xml
Module SignVerifyEnvelope
Sub Main(ByVal args() As String)
Dim Certificate As String = "CN=XMLDSIG_Test"
Try
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "SignedExample.xml", Certificate)
Console.WriteLine("XML file signed.")
If VerifyXmlFile("SignedExample.xml", Certificate) Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Sub SignXmlFile(ByVal FileName As String, ByVal SignedFileName As String, ByVal SubjectName As String)
If Nothing = FileName Then
Throw New ArgumentNullException("FileName")
End If
If Nothing = SignedFileName Then
Throw New ArgumentNullException("SignedFileName")
End If
If Nothing = SubjectName Then
Throw New ArgumentNullException("SubjectName")
End If
' Load the certificate from the certificate store.
Dim cert As X509Certificate2 = GetCertificateBySubject(SubjectName)
' Create a new XML document.
Dim doc As New XmlDocument()
' Format the document to ignore white spaces.
doc.PreserveWhitespace = False
' Load the passed XML file using it's name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = cert.GetRSAPrivateKey()
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Add an enveloped transformation to the reference.
Dim env As New XmlDsigEnvelopedSignatureTransform()
reference.AddTransform(env)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Create a new KeyInfo object.
Dim keyInfo As New KeyInfo()
' Load the certificate into a KeyInfoX509Data object
' and add it to the KeyInfo object.
keyInfo.AddClause(New KeyInfoX509Data(cert))
' Add the KeyInfo object to the SignedXml object.
signedXml.KeyInfo = keyInfo
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
If TypeOf doc.FirstChild Is XmlDeclaration Then
doc.RemoveChild(doc.FirstChild)
End If
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
Try
doc.WriteTo(xmltw)
Finally
xmltw.Close()
End Try
End Sub
' Verify the signature of an XML file against an asymmetric
' algorithm and return the result.
Function VerifyXmlFile(ByVal FileName As String, ByVal CertificateSubject As String) As [Boolean]
' Check the args.
If Nothing = FileName Then
Throw New ArgumentNullException("FileName")
End If
If Nothing = CertificateSubject Then
Throw New ArgumentNullException("CertificateSubject")
End If
' Load the certificate from the store.
Dim cert As X509Certificate2 = GetCertificateBySubject(CertificateSubject)
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Load the passed XML file into the document.
xmlDocument.Load(FileName)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature(cert, True)
End Function
Function GetCertificateBySubject(ByVal CertificateSubject As String) As X509Certificate2
' Check the args.
If Nothing = CertificateSubject Then
Throw New ArgumentNullException("CertificateSubject")
End If
' Load the certificate from the certificate store.
Dim cert As X509Certificate2 = Nothing
Dim store As New X509Store("My", StoreLocation.CurrentUser)
Try
' Open the store.
store.Open(OpenFlags.ReadOnly Or OpenFlags.OpenExistingOnly)
' Get the certs from the store.
Dim CertCol As X509Certificate2Collection = store.Certificates
' Find the certificate with the specified subject.
Dim c As X509Certificate2
For Each c In CertCol
If c.Subject = CertificateSubject Then
cert = c
Exit For
End If
Next c
' Throw an exception of the certificate was not found.
If cert Is Nothing Then
Throw New CryptographicException("The certificate could not be found.")
End If
Finally
' Close the store even if an exception was thrown.
store.Close()
End Try
Return cert
End Function
' Create example data to sign.
Sub CreateSomeXml(ByVal FileName As String)
' Check the args.
If Nothing = FileName Then
Throw New ArgumentNullException("FileName")
End If
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyElement", "samples")
' Add some text to the node.
node.InnerText = "Example text to be signed."
' Append the node to the document.
document.AppendChild(node)
' Save the XML document to the file name specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
Try
document.WriteTo(xmltw)
Finally
xmltw.Close()
End Try
End Sub
End Module
' This code example displays the following to the console:
'
' New XML file created.
' XML file signed.
' The XML signature is valid.
Remarks
In version 1.1 of the .NET Framework, the X.509 certificate is not verified. In version 2.0 and later, the X.509 certificate is verified.
In version 2.0 and later of the .NET Framework, the CheckSignature method will search the "AddressBook" store for certificates suitable for the verification. For example, if the certificate is referenced by a Subject Key Identifier (SKI), the CheckSignature method will select certificates with this SKI and try them one after another until it can verify the certificate.
Applies to
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