(Android™) Create JWT Using RSA (RS256, RS384, or RS512)

Demonstrates how to create a JWT using an RSA private key. This is for JOSE headers with an "alg" of RS256, RS384, or RS512. When RSA is used, the private key signs (creates) the JWT, and the public key is for verification.

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 a JWT using an RSA private key.

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

    CkPrivateKey privKey = new CkPrivateKey();

    // Load an RSA private key from a PEM file.
    boolean success = privKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd");
    if (success != true) {
        Log.i(TAG, privKey.lastErrorText());
        return;
        }

    CkJwt jwt = new CkJwt();

    // Build the JOSE header
    CkJsonObject jose = new CkJsonObject();
    // Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
    success = jose.AppendString("alg","RS256");
    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);

    // Create the JWT token.  This is where the RSA signature is created.
    String token = jwt.createJwtPk(jose.emit(),claims.emit(),privKey);

    Log.i(TAG, token);

  }

  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."
  }
}