Android™

Get RSA Public Key in JWK Format (JSON Web Key)

See more JSON Web Signatures (JWS) Examples

Demonstrates how to get an RSA public key in JWK (JSON Web Key) format.

Note: This example requires Chilkat v9.5.0.66 or later.

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;

    // Note: This example requires Chilkat v9.5.0.66 or later.

    // Load a PEM file into memory.
    CkStringBuilder sbPem = new CkStringBuilder();
    success = sbPem.LoadFile("qa_data/pem/rsa_public.pem","utf-8");
    if (success != true) {
        Log.i(TAG, "Failed to load PEM file.");
        return;
        }

    // Load the PEM into a public key object.
    CkPublicKey pubKey = new CkPublicKey();
    success = pubKey.LoadFromString(sbPem.getAsString());
    if (success != true) {
        Log.i(TAG, pubKey.lastErrorText());
        return;
        }

    // Get the public key in JWK format:
    String jwk = pubKey.getJwk();

    // The GetJwk method will return the JWK in the most compact JSON format possible,
    // as a single line with no extra whitespace.  To get a more human-readable JWK (for this example),
    // load into a Chilkat JSON object and emit non-compact:

    CkJsonObject json = new CkJsonObject();
    json.Load(jwk);
    json.put_EmitCompact(false);
    Log.i(TAG, "RSA Public Key in JWK format:");
    Log.i(TAG, json.emit());

    // Sample output:
    // { 
    //   "kty": "RSA",
    //   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
    //   "e": "AQAB"
    // }

    // Additional information can be added like this:
    json.AppendString("use","enc");
    json.AppendString("kid","123ABC");

    // Now examine the JSON:
    Log.i(TAG, json.emit());

    // { 
    //   "kty": "RSA",
    //   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
    //   "e": "AQAB",
    //   "use": "enc",
    //   "kid": "123ABC"
    // }

  }

  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."
  }
}