(Node.js) ECDSA Sign and Verify Data using Different Hash Algorithms

Demonstrates how to create ECDSA signatures on data using different hash algorithms.

Note: This example requires Chilkat v9.5.0.85 or greater because the SignBd and VerifyBd methods were added in v9.5.0.85.

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

    // First load an ECDSA private key to be used for signing.
    var privKey = new chilkat.PrivateKey();
    var success = privKey.LoadEncryptedPemFile("qa_data/ecc/secp256r1-key-pkcs8-secret.pem","secret");
    if (success == false) {
        console.log(privKey.LastErrorText);
        return;
    }

    // Load some data to be signed.
    var bd = new chilkat.BinData();
    success = bd.LoadFile("qa_data/hamlet.xml");
    if (success == false) {
        console.log("Failed to load file to be hashed.");
        return;
    }

    var ecdsa = new chilkat.Ecc();
    var prng = new chilkat.Prng();

    // Sign the sha256 hash of the data.  Return the ECDSA signature in the base64 encoding.
    console.log("ECDSA signing the sha256 hash of the data...");
    var sig = ecdsa.SignBd(bd,"sha256","base64",privKey,prng);
    console.log("sig = " + sig);

    // Verify the signature against the original data.
    // (We must use the same hash algorithm that was used when signing.)

    // Load the public key that corresponds to the private key used for signing.
    var pubKey = new chilkat.PublicKey();
    success = pubKey.LoadFromFile("qa_data/ecc/secp256r1-pub.pem");
    if (success == false) {
        console.log(pubKey.LastErrorText);
        return;
    }

    var ecc2 = new chilkat.Ecc();
    var result = ecc2.VerifyBd(bd,"sha256",sig,"base64",pubKey);
    if (result !== 1) {
        console.log(ecc2.LastErrorText);
        return;
    }

    console.log("Verified!");

    // ----------------------------------------------------------------------------------------
    // Let's do the same thing, but with sha384 hashing...

    console.log("--------------------------------------------");
    console.log("ECDSA signing the sha384 hash of the data...");

    sig = ecdsa.SignBd(bd,"sha384","base64",privKey,prng);
    console.log("sig = " + sig);

    result = ecc2.VerifyBd(bd,"sha384",sig,"base64",pubKey);
    if (result !== 1) {
        console.log(ecc2.LastErrorText);
        return;
    }

    console.log("Verified!");

}

chilkatExample();