(Node.js) Sign a Byte Array to Create a Detached Signature in a Byte Array

Signs data contained in a byte array to produce a detached signature (also in a byte array). Also shows how to verify the signature.

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 cert = new chilkat.Cert();
    var success = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var fac = new chilkat.FileAccess();

    fileBytes = fac.ReadEntireFile("qa_data/pdf/sample.pdf");
    if (fac.LastMethodSuccess !== true) {
        console.log(fac.LastErrorText);
        return;
    }

    var crypt = new chilkat.Crypt2();

    success = crypt.SetSigningCert(cert);

    // We can sign any type of file.
    // The result is a detached signature (a signature that does not contain the data being signed).

    sigBytes = crypt.SignBytes(fileBytes);
    if (crypt.LastMethodSuccess !== true) {
        console.log(crypt.LastErrorText);
        return;
    }

    success = fac.WriteEntireFile("qa_output/sample.pdf.p7s",sigBytes);
    if (fac.LastMethodSuccess !== true) {
        console.log(fac.LastErrorText);
        return;
    }

    // We can verify the detached signature like this
    var verified = crypt.VerifyBytes(fileBytes,sigBytes);
    if (crypt.LastMethodSuccess !== true) {
        console.log(crypt.LastErrorText);
        return;
    }

    console.log("Verified = " + verified);

}

chilkatExample();