(Node.js) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var dsig = new chilkat.XmlDSig();
    var sbXml = new chilkat.StringBuilder();

    var success = sbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8");
    if (success !== true) {
        console.log("Failed to load XML file.");
        return;
    }

    success = dsig.LoadSignatureSb(sbXml);
    if (success !== true) {
        console.log(dsig.LastErrorText);
        return;
    }

    // Get the KeyInfo XML.
    // xmlKeyInfo: Xml
    var xmlKeyInfo = dsig.GetKeyInfo();
    if (dsig.LastMethodSuccess !== true) {
        console.log(dsig.LastErrorText);
        return;
    }

    console.log(xmlKeyInfo.GetXml());
    console.log("----");

    // Assuming the X509Certificate is in the KeyInfo, it will look like this:

    //   <ds:KeyInfo Id="...">
    //     <ds:KeyValue>
    //     ...  
    //     <ds:X509Data>
    //       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
    //     </ds:X509Data>
    //   </ds:KeyInfo>
    var certBase64 = xmlKeyInfo.GetChildContent("*:X509Data|*:X509Certificate");
    if (xmlKeyInfo.LastMethodSuccess !== true) {
        console.log("No X509Certificate found in the KeyInfo.");
        return;
    }

    // Load a certificate object w/ the base64.
    var cert = new chilkat.Cert();
    success = cert.LoadFromBase64(certBase64);
    if (success !== true) {
        console.log(cert.LastErrorText);
        return;
    }

    // Examine the cert..
    console.log("SubjectDN: " + cert.SubjectDN);
    console.log("IssuerDN: " + cert.IssuerDN);
    console.log("SerialNumber as Decimal: " + cert.SerialDecimal);


}

chilkatExample();