Sign a JWS with an HMAC Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetMacKey, which sets the symmetric MAC key for a signature. The key bytes are supplied in a named encoding such as hex or base64.

// 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;

    CkJws jws = new CkJws();

    //  Protected header specifying HMAC-SHA256.
    CkJsonObject header = new CkJsonObject();
    header.UpdateString("alg","HS256");
    success = jws.SetProtectedHeader(0,header);
    if (success == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    boolean bIncludeBom = false;
    success = jws.SetPayload("This is the content to sign.","utf-8",bIncludeBom);
    if (success == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    //  Set the symmetric MAC key for signature 0.  The key bytes are provided in the named encoding (here
    //  base64).  In production, obtain the key from a secure source rather than hard-coding it.
    String base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = jws.SetMacKey(0,base64Key,"base64");
    if (success == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    String jwsCompact = jws.createJws();
    if (jws.get_LastMethodSuccess() == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    Log.i(TAG, jwsCompact);

  }

  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."
  }
}