Android™

Export a Private Key as a JWK

Demonstrates the Chilkat PrivateKey.GetJwk method, which exports the key as a compact JWK (JSON Web Key). It takes no arguments; binary values use Base64url without padding.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: JWK is the JSON key format used across modern web security — JWT, OAuth, OpenID Connect. Exporting to it lets you publish a key into a JWK Set or hand it to a web framework that speaks JWK. Note this is the private JWK: it includes the private parameters (d and, for RSA, the CRT values), so it is highly sensitive — publish only the public JWK derived from ToPublicKey when sharing.

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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;

    //  Load a private key to export.
    CkPrivateKey privKey = new CkPrivateKey();
    success = privKey.LoadPemFile("qa_data/private.pem");
    if (success == false) {
        Log.i(TAG, privKey.lastErrorText());
        return;
        }

    //  Export as a compact JWK (JSON Web Key).  Binary values use Base64url without padding.
    String jwk = privKey.getJwk();
    if (privKey.get_LastMethodSuccess() == false) {
        Log.i(TAG, privKey.lastErrorText());
        return;
        }

    Log.i(TAG, jwk);

  }

  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."
  }
}