KeyInfoX509Data Class

Definition

Represents an <X509Data> subelement of an XMLDSIG or XML Encryption <KeyInfo> element.

C#
public class KeyInfoX509Data : System.Security.Cryptography.Xml.KeyInfoClause
Inheritance
KeyInfoX509Data

Examples

This section contains two code examples. The first example demonstrates how to sign an XML file using a detached signature. The second example demonstrates how to sign an XML file using an envelope signature.

Example #1

C#
//
// 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.Security.Cryptography.X509Certificates;
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";

        // The name of the X509 certificate
        string Certificate = "microsoft.cer";

        try
        {

            // Generate a signing key. This key should match the certificate.
            RSA Key = RSA.Create();

            Console.WriteLine("Signing: {0}", resourceToSign);

            // Sign the detached resourceand save the signature in an XML file.
            SignDetachedResource(resourceToSign, XmlFileName, Key, Certificate);

            Console.WriteLine("XML signature was successfully computed and saved to {0}.", XmlFileName);
        }
        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, RSA Key, string Certificate)
    {
        // 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);

        // Create a new KeyInfo object.
        KeyInfo keyInfo = new KeyInfo();

        // Load the X509 certificate.
        X509Certificate MSCert = X509Certificate.CreateFromCertFile(Certificate);
 
        // Load the certificate into a KeyInfoX509Data object
        // and add it to the KeyInfo object.
        keyInfo.AddClause(new KeyInfoX509Data(MSCert));
  
        // 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();

        // 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();
    }
}

Example #2

C#
//
// 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.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml;

public class SignVerifyEnvelope
{

    public static void Main(String[] args)
    {

        string Certificate =  "microsoft.cer";

        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, Certificate);
            Console.WriteLine("XML file signed."); 
        }
        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, RSA Key, string Certificate)
    {
        // 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;

        // 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 X509 certificate.
        X509Certificate MSCert = X509Certificate.CreateFromCertFile(Certificate);
 
        // Load the certificate into a KeyInfoX509Data object
        // and add it to the KeyInfo object.
        keyInfo.AddClause(new KeyInfoX509Data(MSCert));
  
        // 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.
        XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
        doc.WriteTo(xmltw);
        xmltw.Close();
    }

    // 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();
    }
}

Remarks

The KeyInfoX509Data class represents the <X509Data> element that contains X.509v3 certificate information related to the validation or encryption key. For example, an <X509Data> element might contain an X.509 certificate whose subject public key is the validation key, or a chain of X.509 certificates that terminate in a certificate for the validating key, or other identifiers for related X.509 certificates.

Use the KeyInfoX509Data class whenever you need to include X.509 certificate data in an encrypted or signed XML document.

For more information about the <X509Data> element, see Section 4.4.4 of the XMLDSIG specification or the XML Encryption specification, which are available on the W3C website.

Constructors

KeyInfoX509Data()

Initializes a new instance of the KeyInfoX509Data class.

KeyInfoX509Data(Byte[])

Initializes a new instance of the KeyInfoX509Data class from the specified ASN.1 DER encoding of an X.509v3 certificate.

KeyInfoX509Data(X509Certificate, X509IncludeOption)

Initializes a new instance of the KeyInfoX509Data class from the specified X.509v3 certificate.

KeyInfoX509Data(X509Certificate)

Initializes a new instance of the KeyInfoX509Data class from the specified X.509v3 certificate.

Properties

Certificates

Gets a list of the X.509v3 certificates contained in the KeyInfoX509Data object.

CRL

Gets or sets the Certificate Revocation List (CRL) contained within the KeyInfoX509Data object.

IssuerSerials

Gets a list of X509IssuerSerial structures that represent an issuer name and serial number pair.

SubjectKeyIds

Gets a list of the subject key identifiers (SKIs) contained in the KeyInfoX509Data object.

SubjectNames

Gets a list of the subject names of the entities contained in the KeyInfoX509Data object.

Methods

AddCertificate(X509Certificate)

Adds the specified X.509v3 certificate to the KeyInfoX509Data.

AddIssuerSerial(String, String)

Adds the specified issuer name and serial number pair to the KeyInfoX509Data object.

AddSubjectKeyId(Byte[])

Adds the specified subject key identifier (SKI) byte array to the KeyInfoX509Data object.

AddSubjectKeyId(String)

Adds the specified subject key identifier (SKI) string to the KeyInfoX509Data object.

AddSubjectName(String)

Adds the subject name of the entity that was issued an X.509v3 certificate to the KeyInfoX509Data object.

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
GetXml()

Returns an XML representation of the KeyInfoX509Data object.

LoadXml(XmlElement)

Parses the input XmlElement object and configures the internal state of the KeyInfoX509Data object to match.

MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to

Product Versions
.NET 8 (package-provided), 9 (package-provided)
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7 (package-provided), 4.7, 4.7.1 (package-provided), 4.7.1, 4.7.2 (package-provided), 4.7.2, 4.8 (package-provided), 4.8, 4.8.1
.NET Standard 2.0 (package-provided)
Windows Desktop 3.0, 3.1, 5, 6, 7, 8, 9