(Node.js) JWS Using HMAC SHA-256

Creates a JSON Web Signatures (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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.

    // Note: This example requires Chilkat v9.5.0.66 or greater.

    var success;

    // First create the JWS Protected Header
    var jwsProtHdr = new chilkat.JsonObject();
    jwsProtHdr.AppendString("typ","JWT");
    jwsProtHdr.AppendString("alg","HS256");
    console.log("JWS Protected Header: " + jwsProtHdr.Emit());

    // Output:
    // JWS Protected Header: {"typ":"JWT","alg":"HS256"}

    var jws = new chilkat.Jws();

    // Set the HMAC key:
    var hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow";
    var signatureIndex = 0;
    jws.SetMacKey(signatureIndex,hmacKey,"base64url");

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

    // 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: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

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

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

    // Set the MAC key used for validation.
    signatureIndex = 0;
    jws2.SetMacKey(signatureIndex,hmacKey,"base64url");

    // 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 MAC 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:
    // 	{ 
    // 	  "typ": "JWT",
    // 	  "alg": "HS256"
    // 	} 

}

chilkatExample();