(JavaScript) Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Note: This example requires Chilkat v11.0.0 or greater.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var success = false;

// 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 CkCert();
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:
var privKey = new CkPrivateKey();
success = cert.GetPrivateKey(privKey);
if (success == 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 CkJsonObject();
jwsProtHdr.AppendString("alg","RS256");

var jws = new CkJws();

// 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 == false) {
    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 CkJws();

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

var rsaPubKey = new CkPublicKey();
privKey.ToPublicKey(rsaPubKey);

// 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:

var joseHeader = new CkJsonObject();
success = jws2.GetProtectedH(signatureIndex,joseHeader);
if (success == false) {
    console.log(jws2.LastErrorText);
    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"
// 	}