(Node.js) Verify JWT Using HS256, HS384, or HS512

Demonstrates how to verify a JWT that was signed using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.)

This example verifies the signature. It also does the following:

• Checks to see if the time constraints ("nbf" and "exp") are valid.
• Recovers the original JOSE header.
• Recovers the original claims JSON.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    // Demonstrates how to verify an HMAC JWT using a shared secret (password).

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

    var jwt = new chilkat.Jwt();

    var token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDMxODEyLCJuYmYiOjE0NjM0MzE4MTIsImV4cCI6MTQ2MzQzNTQxMn0.SHnMJ11qJH5pbp22YchT_9fL2HIx0koHiUHLG67_foU";

    // First verify the signature.
    // The password used to create this JWT was "secret".
    var sigVerified = jwt.VerifyJwt(token,"secret");
    console.log("with correct password: " + sigVerified);

    // Now try with a different password:
    sigVerified = jwt.VerifyJwt(token,"secret2");
    console.log("with incorrect password " + sigVerified);

    // Let's see if the time constraints, if any, are valid.
    // The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
    // If the current system time is before the "nbf" time, or after the "exp" time,
    // then IsTimeValid will return false/0.
    // Also, we'll allow a leeway of 60 seconds to account for any clock skew.
    // Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
    var leeway = 60;
    var bTimeValid = jwt.IsTimeValid(token,leeway);
    console.log("time constraints valid: " + bTimeValid);

    // Now let's recover the original claims JSON (the payload).
    var payload = jwt.GetPayload(token);
    // The payload will likely be in compact form:
    console.log(payload);

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    var json = new chilkat.JsonObject();
    var success = json.Load(payload);
    json.EmitCompact = false;
    console.log(json.Emit());

    // We can recover the original JOSE header in the same way:
    var joseHeader = jwt.GetHeader(token);
    // The payload will likely be in compact form:
    console.log(joseHeader);

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    success = json.Load(joseHeader);
    json.EmitCompact = false;
    console.log(json.Emit());

}

chilkatExample();