Android™

Verify JWT Using HS256, HS384, or HS512

See more JSON Web Token (JWT) Examples

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.

Android™

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

    //  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.

    CkJwt jwt = new CkJwt();

    String token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDMxODEyLCJuYmYiOjE0NjM0MzE4MTIsImV4cCI6MTQ2MzQzNTQxMn0.SHnMJ11qJH5pbp22YchT_9fL2HIx0koHiUHLG67_foU";

    //  First verify the signature.
    //  The password used to create this JWT was "secret".
    boolean sigVerified = jwt.VerifyJwt(token,"secret");
    Log.i(TAG, "with correct password: " + String.valueOf(sigVerified));

    //  Now try with a different password:
    sigVerified = jwt.VerifyJwt(token,"secret2");
    Log.i(TAG, "with incorrect password " + String.valueOf(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);
    Log.i(TAG, "time constraints valid: " + String.valueOf(bTimeValid));

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

    //  We can format for human viewing by loading it into Chilkat's JSON object
    //  and emit.
    CkJsonObject json = new CkJsonObject();
    success = json.Load(payload);
    json.put_EmitCompact(false);
    Log.i(TAG, 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:
    Log.i(TAG, joseHeader);

    //  We can format for human viewing by loading it into Chilkat's JSON object
    //  and emit.
    success = json.Load(joseHeader);
    json.put_EmitCompact(false);
    Log.i(TAG, json.emit());

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}