(Android™) Load EC Public Key from X,Y Values

Demonstrates how to load an EC public key from X and Y values.

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);

    boolean success;

    // We have the following x and y values in base64 (for an EC point on the P-256 curve).
    String x = "Dn7uB1O7kgk74G6qfQwFJESeDnxO6lLjGZFWZJE16tw";
    String y = "iOWA5DInzK6nuUGvHJbMVq1Dpj248FqSV2teN3HzmhU";

    // Build a JWK that looks like this:

    // {
    //   "kty": "EC",
    //   "crv": "P-256",
    //   "x": "Dn7uB1O7kgk74G6qfQwFJESeDnxO6lLjGZFWZJE16tw",
    //   "y": "iOWA5DInzK6nuUGvHJbMVq1Dpj248FqSV2teN3HzmhU"
    // }

    CkJsonObject json = new CkJsonObject();
    json.UpdateString("kty","EC");
    json.UpdateString("crv","P-256");
    json.UpdateString("x",x);
    json.UpdateString("y",y);

    // Load from the JWK.
    CkPublicKey pubkey = new CkPublicKey();
    success = pubkey.LoadFromString(json.emit());
    if (success == false) {
        Log.i(TAG, pubkey.lastErrorText());
        return;
        }

    Log.i(TAG, "Success.");

  }

  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."
  }
}