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Android™

Get a JWS Protected Header

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.GetProtectedH, which copies the decoded protected header of a signature into a JsonObject.

Background. The protected header is integrity-protected by the signature. Inspecting it (for example the alg value) is useful before deciding how to validate.

Chilkat Android™ Downloads

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;

    CkJws jws = new CkJws();

    //  Load the JWS compact serialization.
    String jwsCompact = "eyJhbGciOiJIUzI1NiJ9.VGhpcyBpcyB0aGUgY29udGVudCB0byBzaWduLg.<signature>";
    success = jws.LoadJws(jwsCompact);
    if (success == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    //  Copy the decoded protected header of signature 0 into a JsonObject.
    CkJsonObject json = new CkJsonObject();
    success = jws.GetProtectedH(0,json);
    if (success == false) {
        Log.i(TAG, jws.lastErrorText());
        return;
        }

    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."
  }
}