(Node.js) Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

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

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

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

    var pubKey = new chilkat.PublicKey();

    // Load the public key from an PEM file:
    var success = pubKey.LoadFromFile("pubKey.pem");
    if (success !== true) {
        console.log(pubKey.LastErrorText);
        return;
    }

    // Load the data of the original file that was signed.
    var bdFileData = new chilkat.BinData();
    success = bdFileData.LoadFile("in.dat");

    // Load the signature.
    var bdSig = new chilkat.BinData();
    success = bdSig.LoadFile("signature.sig");

    var rsa = new chilkat.Rsa();

    // Import the public key into the RSA component:
    success = rsa.ImportPublicKeyObj(pubKey);
    if (success !== true) {
        console.log(rsa.LastErrorText);
        return;
    }

    // OpenSSL uses big-endian.
    rsa.LittleEndian = false;

    success = rsa.VerifyBd(bdFileData,"sha256",bdSig);
    if (success !== true) {
        console.log(rsa.LastErrorText);
        console.log("The signature was invalid.");
        return;
    }

    console.log("The signature was verified.");

}

chilkatExample();