Java Requires Chilkat v11.0.0+

Verify a JWT Created by the Amazon Cognito Service

See more JSON Web Token (JWT) Examples

Demonstrates how to verify a JWT created by the Amazon Cognito Service. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Http;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Jwt;
import com.chilkatsoft.chilkat2.PublicKey;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // The public keys for this example are at https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json
        // Let's get them:

        Http http = new Http();
        StringBuilder sbJsonKeys = new StringBuilder();
        try {
            http.quickGetSb("https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json", sbJsonKeys);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        JsonObject jsonKeys = new JsonObject();
        jsonKeys.loadSb(sbJsonKeys);
        jsonKeys.setEmitCompact(false);
        System.out.println(jsonKeys.emit());

        // Here are the keys:

        // {
        //   "keys": [
        //     {
        //       "alg": "RS256",
        //       "e": "AQAB",
        //       "kid": "1A/L5Fsb2EsEwxy5E0cmCMS1BnMe6Jl6NXiMig4iNwU=",
        //       "kty": "RSA",
        //       "n": "y0w7BJrIJYi ... jKG27z2P3OKw",
        //       "use": "sig"
        //     },
        //     {
        //       "alg": "RS256",
        //       "e": "AQAB",
        //       "kid": "mos6VTJnvDwurY3ghJg6IAPUq+dMwl6CL/iThzJOkzg=",
        //       "kty": "RSA",
        //       "n": "qbIEH-7tg6yrT ... 3Fj94ooTd0w",
        //       "use": "sig"
        //     }
        //   ]
        // }

        // Try the 1st key.
        JsonObject jsonKey1 = new JsonObject();
        jsonKeys.objectOf2("keys[0]", jsonKey1);

        PublicKey pubKey1 = new PublicKey();
        try {
            pubKey1.loadFromString(jsonKey1.emit());
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Success");

        Jwt jwt = new Jwt();

        // I did not include the an actual AWS Cognito token here because our test sample used customer-provided data..
        String token = "eyJ..asXg";

        // First verify the signature.
        boolean sigVerified;
        try {
            jwt.verifyJwtPk(token, pubKey1);
            sigVerified = true;
        } catch (ChilkatException e) {
            sigVerified = false;
        }
        System.out.println("verified: " + 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.
        int leeway = 60;
        boolean bTimeValid = jwt.isTimeValid(token, leeway);
        System.out.println("time constraints valid: " + bTimeValid);

        // Now let's recover the original claims JSON (the payload).
        String payload = jwt.getPayload(token);
        // The payload will likely be in compact form:
        System.out.println(payload);

        // We can format for human viewing by loading it into Chilkat's JSON object
        // and emit.
        JsonObject json = new JsonObject();
        json.load(payload);
        json.setEmitCompact(false);
        System.out.println(json.emit());

        // We can recover the original JOSE header in the same way:
        String joseHeader = jwt.getHeader(token);
        // The payload will likely be in compact form:
        System.out.println(joseHeader);

        // We can format for human viewing by loading it into Chilkat's JSON object
        // and emit.
        json.load(joseHeader);
        json.setEmitCompact(false);
        System.out.println(json.emit());
    }
}