(Android™) Create JWT Using HS256, HS384, or HS512

Demonstrates how to create a JWT using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.) When HMAC is used, the secret is a shared secret (i.e. password) that both client and server know beforehand.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// 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);

    // Demonstrates how to create 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();

    // Build the JOSE header
    CkJsonObject jose = new CkJsonObject();
    // Use HS256.  Pass the string "HS384" or "HS512" to use a different algorithm.
    boolean success = jose.AppendString("alg","HS256");
    success = jose.AppendString("typ","JWT");

    // Now build the JWT claims (also known as the payload)
    CkJsonObject claims = new CkJsonObject();
    success = claims.AppendString("iss","http://example.org");
    success = claims.AppendString("sub","John");
    success = claims.AppendString("aud","http://example.com");

    // Set the timestamp of when the JWT was created to now.
    int curDateTime = jwt.GenNumericDate(0);
    success = claims.AddIntAt(-1,"iat",curDateTime);

    // Set the "not process before" timestamp to now.
    success = claims.AddIntAt(-1,"nbf",curDateTime);

    // Set the timestamp defining an expiration time (end time) for the token
    // to be now + 1 hour (3600 seconds)
    success = claims.AddIntAt(-1,"exp",curDateTime + 3600);

    // Produce the smallest possible JWT:
    jwt.put_AutoCompact(true);

    String strJwt = jwt.createJwt(jose.emit(),claims.emit(),"secret");

    Log.i(TAG, strJwt);

  }

  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."
  }
}