(Node.js) Verify a Google JWT Using Google's Public Key

See more Google APIs Examples

Demonstrates how to verify a JWT that was signed using Google's RSA private key.

This example verifies the RSA 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, 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 example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var http = new chilkat.Http();
    var sbPubKeys = new chilkat.StringBuilder();

    var success = http.QuickGetSb("https://www.googleapis.com/oauth2/v3/certs",sbPubKeys);
    if (success == false) {
        console.log(http.LastErrorText);
        return;
    }

    console.log(sbPubKeys.GetAsString());

    // Here are the keys:

    // {
    //   "keys": [
    //     {
    //       "e": "AQAB",
    //       "n": "4bAT6C6EeX8Dspje3FrAXw-nnhNk04e1RmNa4kjc0CHf6Pk7ryARlwA-6YilyPABqQfYHx60s8oSnxvUVprFfQ2-Q8aAZO7bPKSxnoGlcKERL2oLNA4Msvc89N9Y5ycThZUplf_QC19e6jyYXN6Nz-UnJSCLrtQY8tVhhVRs61j4A2N_p-enAi-r704Qi1-v-DKV4eVRkClKViploo8NyjUaT9L4vbBssPCjyimJzsWnEe1fED5c4LnHeArYzA_FEn3JJotqDIz9t2VnvZNTMhizHEX4VnORlEWMEfR8n4CEHQx7PcQUOmfqyw08gWeXQl1-uTjtIGaE-sRIv9u_vQ",
    //       "kty": "RSA",
    //       "use": "sig",
    //       "alg": "RS256",
    //       "kid": "2af90e87be140c20038898a6efa11283dab6031d"
    //     },
    //     {
    //       "n": "nzGsrziOYrMVYMpvUZOwkKNiPWcOPTYRYlDSdRW4UpAHdWPbPlyqaaphYhoMB5DXrVxI3bdvm7DOlo-sHNnulmAFQa-7TsQMxrZCvVdAbyXGID9DZYEqf8mkCV1Ohv7WY5lDUqlybIk1OSHdK7-1et0QS8nn-5LojGg8FK4ssLf3mV1APpujl27D1bDhyRb1MGumXYElwlUms7F9p9OcSp5pTevXCLmXs9MJJk4o9E1zzPpQ9Ko0lH9l_UqFpA7vwQhnw0nbh73rXOX2TUDCUqL4ThKU5Z9Pd-eZCEOatKe0mJTpQ00XGACBME_6ojCdfNIJr84Y_IpGKvkAEksn9w",
    //       "use": "sig",
    //       "kid": "87bbe0815b064e6d449cac999f0e50e72a3e4374",
    //       "e": "AQAB",
    //       "alg": "RS256",
    //       "kty": "RSA"
    //     }
    //   ]
    // }

    // -------------------------------------------------------------------------------------------
    // Replace this with your actual token.
    // This sample token contains a kid that does not match any of the above Google public keys.
    // -------------------------------------------------------------------------------------------
    var token = "eyJhbGciOiJSUzI1NiIsImtpZCI6IjQyZmY5MGQ3ZDM0OGM5NzM4MWE3YzExOWVmMWY1MzI0ZWEzZjViZWIifQ.eyJpc3MiOiJodHRwczovL2FjY291bnRzLmdvb2dsZS5jb20iLCJzdWIiOiIxMTExMTExMTExMTExMTExMTExMTExMTExMTExMTExMTExMTExMTExMTExIiwiaWF0IjoxNjExMTE1MTQzLCJleHAiOjE2MTEyMDE1NDMsImF1ZCI6IjQyOTc1NzExNTE0ODg0OSJ9.pLem5i0bx3M7lJYj7jKv2Nq7c07X5YpZz-x1uM5RniW-v4LsX-lKIVvOq2x3-WoPqkzLXJfP0kG0dx1uD2q1NfFQK60YwKH4FnFtB6INnUP1dRVpP9_pTTKyAE28I3s5Tay4PbPdrCl7ZLCIJzCfpCW1TiWeVoPjp5HgZKTBHdP_sEkN_yO5dQerQXAkFJkV3kNgF9jI3ayT-KPqOIH6GVoWXjHFDyA2EYgJPEFRo5WSe6XycJ85p5duwT-OoBcb_kJZG9PxYd91eHlPCzp8vGxzIb2dVROCBxyM8e8W0cd9v15hfmpg9R-eG9vCM5y63ZLChZLFeHFx0Pd7hvAqfKg";

    var jwt = new chilkat.Jwt();
    var header = jwt.GetHeader(token);

    console.log(header);

    // Sample header:
    // {"alg":"RS256","kid":"87bbe0815b064e6d449cac999f0e50e72a3e4374"}

    // Load the public key matching the "kid" into a Chilkat public key object, then verify..

    var json = new chilkat.JsonObject();
    json.Load(header);
    var kid = json.StringOf("kid");

    console.log("kid = " + kid);

    var jsonPubKeys = new chilkat.JsonObject();
    jsonPubKeys.LoadSb(sbPubKeys);

    // jsonKey: JsonObject
    var jsonKey = jsonPubKeys.FindRecord("keys","kid",kid,true);
    if (jsonPubKeys.LastMethodSuccess == false) {
        console.log("Did not find a matching public key based on the kid.");
        return;
    }

    console.log(jsonKey.Emit());

    // Load the matching public key into a Chilkat public key object.
    var pubKey = new chilkat.PublicKey();
    success = pubKey.LoadFromString(jsonKey.Emit());

    if (success == false) {
        console.log(pubKey.LastErrorText);
        return;
    }

    // ----------------------------------------------------------------------------------------
    // Now we can validate the JWT using Google's public key as shown in this example:
    // (Except we use the public key obtained as shown above instead of a public key loaded from a PEM file.
    // 
    // See Verify JWT Using an RSA Public Key

}

chilkatExample();