Node.js

ECDSA Sign and Verify Data using Different Hash Algorithms

See more ECC Examples

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.

Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    //  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();
    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();