Reference Class
Represents the <reference> element of an XML signature.
Assembly: System.Security (in System.Security.dll)
The Reference type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | Reference() | Initializes a new instance of the Reference class with default properties. |
![]() | Reference(Stream) | Initializes a new instance of the Reference class with a hash value of the specified Stream. |
![]() | Reference(String) | Initializes a new instance of the Reference class with the specified Uri. |
| Name | Description | |
|---|---|---|
![]() | DigestMethod | Gets or sets the digest method Uniform Resource Identifier (URI) of the current Reference. |
![]() | DigestValue | Gets or sets the digest value of the current Reference. |
![]() | Id | Gets or sets the ID of the current Reference. |
![]() | TransformChain | Gets the transform chain of the current Reference. |
![]() | Type | Gets or sets the type of the object being signed. |
![]() | Uri | Gets or sets the Uri of the current Reference. |
| Name | Description | |
|---|---|---|
![]() | AddTransform | Adds a Transform object to the list of transforms to be performed on the data before passing it to the digest algorithm. |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | GetXml | Returns the XML representation of the Reference. |
![]() | LoadXml | Loads a Reference state from an XML element. |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
The Reference object represents the <reference> element of an XML digital signature defined by the XML digital signature specification.
Use the Reference object to specify the following information:
The digest algorithm used to sign of the data object. This value is required.
The Uniform Resource Identifier (URI) of the data object to sign. The URI can specify a file path or specific elements within an XML document. This value is required.
A chain of transforms to apply before generating the digest. This value is optional.
The type of object to sign. This value is optional.
A unique identifier used to reference the current <reference> element. This value is optional.
For more information about the <reference> element, see the W3C specification at www.w3.org/TR/xmldsig-core/.
Note |
|---|
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
The following code example demonstrates how to generate and verify an enveloped XML signature using the Reference object.
// // 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, RSA^ 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 ); // 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 ); // Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate). KeyInfo^ keyInfo = gcnew KeyInfo; keyInfo->AddClause( gcnew RSAKeyValue( safe_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 ( (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 ) { // 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(); } // 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. RSACryptoServiceProvider^ Key = gcnew RSACryptoServiceProvider; // 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" ); // 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 ); } }
The following code example demonstrates how to generate and verify a detached XML signature using the Reference object.
// // 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, 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 ); // Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate). KeyInfo^ keyInfo = gcnew KeyInfo; keyInfo->AddClause( gcnew RSAKeyValue( safe_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(); // 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 ) { // Create a new XML document. XmlDocument^ xmlDocument = gcnew XmlDocument; // Load the passed XML 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( safe_cast<XmlElement^>(nodeList->Item( 0 )) ); // Check the signature and return the result. return signedXml->CheckSignature(); } [STAThread] int main() { array<String^>^args = Environment::GetCommandLineArgs(); // 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. RSACryptoServiceProvider^ Key = gcnew RSACryptoServiceProvider; 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 succesfully 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 ); // 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 ); } }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
