(Node.js) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card.

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

    // Load the certificate from a smart card.
    var cert = new chilkat.Cert();
    var success = cert.LoadFromSmartcard("");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    // Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
    // such as selecting a certificate if the card contains multiple certificates with private keys,
    // or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

    // If the associated private key was present on the smartcard, then you can simply
    // get it from the Chilkat cert object:
    // privKey: PrivateKey
    var privKey = cert.ExportPrivateKey();
    if (cert.LastMethodSuccess == false) {
        console.log(cert.LastErrorText);
        return;
    }

    // You can check the key type to make sure it's RSA.
    // This will output "rsa" if the key is RSA.
    console.log("Key type = " + privKey.KeyType);

    // Create the JWS Protected Header
    var jwsProtHdr = new chilkat.JsonObject();
    jwsProtHdr.AppendString("alg","RS256");

    var jws = new chilkat.Jws();

    // Set the protected header:
    var signatureIndex = 0;
    jws.SetProtectedHeader(signatureIndex,jwsProtHdr);

    // Set the RSA key:
    jws.SetPrivateKey(signatureIndex,privKey);

    // Set the payload.
    var bIncludeBom = false;
    var payloadStr = "In our village, folks say God crumbles up the old moon into stars.";
    jws.SetPayload(payloadStr,"utf-8",bIncludeBom);

    // Create the JWS
    // By default, the compact serialization is used.
    var jwsCompact = jws.CreateJws();
    if (jws.LastMethodSuccess !== true) {
        console.log(jws.LastErrorText);

        return;
    }

    console.log("JWS: " + jwsCompact);

    // sample output:
    // JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

    // Now load the JWS, validate, and recover the original text.
    var jws2 = new chilkat.Jws();

    // Load the JWS.
    success = jws2.LoadJws(jwsCompact);

    // rsaPubKey: PublicKey
    var rsaPubKey = privKey.GetPublicKey();

    // Set the RSA public key used for validation.
    signatureIndex = 0;
    jws2.SetPublicKey(signatureIndex,rsaPubKey);

    // Validate the 1st (and only) signature at index 0..
    var v = jws2.Validate(signatureIndex);
    if (v < 0) {
        // Perhaps Chilkat was not unlocked or the trial expired..
        console.log("Method call failed for some other reason.");
        console.log(jws2.LastErrorText);
        return;
    }

    if (v == 0) {
        console.log("Invalid signature.  The RSA key was incorrect, the JWS was invalid, or both.");
        return;
    }

    // If we get here, the signature was validated..
    console.log("Signature validated.");

    // Recover the original content:
    console.log(jws2.GetPayload("utf-8"));

    // Examine the protected header:
    // joseHeader: JsonObject
    var joseHeader = jws2.GetProtectedHeader(signatureIndex);
    if (jws2.LastMethodSuccess !== true) {
        console.log("No protected header found at the given index.");
        return;
    }

    joseHeader.EmitCompact = false;

    console.log("Protected (JOSE) header:");
    console.log(joseHeader.Emit());

    // Output:

    // 	Signature validated.
    // 	In our village, folks say God crumbles up the old moon into stars.
    // 	Protected (JOSE) header:
    // 	{ 
    // 	  "alg": "RS256"
    // 	}

}

chilkatExample();