DSAKeyValue Class
Represents the DSA private key of the <KeyInfo> element.
System.Security.Cryptography.Xml::KeyInfoClause
System.Security.Cryptography.Xml::DSAKeyValue
Assembly: System.Security (in System.Security.dll)
The DSAKeyValue type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | DSAKeyValue() | Initializes a new instance of the DSAKeyValue class with a new, randomly-generated DSA public key. |
![]() | DSAKeyValue(DSA) | Initializes a new instance of the DSAKeyValue class with the specified DSA public key. |
| Name | Description | |
|---|---|---|
![]() | 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 a DSAKeyValue element. (Overrides KeyInfoClause::GetXml().) |
![]() | LoadXml | Loads a DSAKeyValue state from an XML element. (Overrides KeyInfoClause::LoadXml(XmlElement).) |
![]() | 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 KeyInfo class represents the <KeyInfo> element, which contains a DSA public key.
Use DSAKeyValue to identify the public key that corresponds to the DSA private key that was used to create the digital signature.
If a key is not explicitly supplied to the constructor, a new DSA key pair is randomly generated.
The DSAKeyValue class is used with XML signatures. For more information about the W3C specification, see http://www.w3.org/TR/xmldsig-core/.
Note |
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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 use the DSAKeyValue class in XML encryption to create 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, DSA^ DSAKey ) { // Create a SignedXml Object*. SignedXml^ signedXml = gcnew SignedXml; // Assign the DSA key to the SignedXml object. signedXml->SigningKey = DSAKey; // 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 a DSAKeyValue to the KeyInfo (optional; helps recipient find key to validate). KeyInfo^ keyInfo = gcnew KeyInfo; keyInfo->AddClause( gcnew DSAKeyValue( safe_cast<DSA^>(DSAKey) ) ); 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 S"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 DSA signing key. DSACryptoServiceProvider^ DSAKey = gcnew DSACryptoServiceProvider; Console::WriteLine( "Signing: {0}", resourceToSign ); // Sign the detached resourceand save the signature in an XML file. SignDetachedResource( resourceToSign, XmlFileName, DSAKey ); 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 ); } }
The following code example demonstrates how to use the DSAKeyValue class in XML encryption to create an envelope 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::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, DSA^ DSAKey ) { // 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 DSA key to the SignedXml document. signedXml->SigningKey = DSAKey; // Create a reference to be signed. Reference^ reference = gcnew Reference; reference->Uri = ""; // Add a transformation to the reference. Transform^ trns = gcnew XmlDsigC14NTransform; reference->AddTransform( trns ); // 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 a DSAKeyValue to the KeyInfo (optional; helps recipient find key to validate). KeyInfo^ keyInfo = gcnew KeyInfo; keyInfo->AddClause( gcnew DSAKeyValue( safe_cast<DSA^>(DSAKey) ) ); 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 DSA signing key. DSACryptoServiceProvider^ DSAKey = gcnew DSACryptoServiceProvider; // 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", DSAKey ); 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 ); } }
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.
