Android™

Export a Public Key as PEM

Demonstrates the Chilkat PublicKey.GetPem method, which returns the public key in PEM format. The only argument selects the underlying DER representation: true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.

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: PEM is the most portable way to share a public key — the Base64 text block most tooling reads. The boolean picks the encoding: false produces the modern, algorithm-independent PUBLIC KEY (SubjectPublicKeyInfo), which is the usual choice; true produces the older RSA-specific RSA PUBLIC KEY for tools that require it. A public key is not sensitive, so the PEM can be distributed openly.

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// 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 public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
    //  JWK, and other supported representations.
    CkPublicKey pubKey = new CkPublicKey();
    success = pubKey.LoadFromFile("qa_data/public.pem");
    if (success == false) {
        Log.i(TAG, pubKey.lastErrorText());
        return;
        }

    //  Export the public key in PEM format.  The argument selects the underlying DER representation:
    //  true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.
    boolean preferPkcs1 = false;
    String pem = pubKey.getPem(preferPkcs1);
    if (pubKey.get_LastMethodSuccess() == false) {
        Log.i(TAG, pubKey.lastErrorText());
        return;
        }

    Log.i(TAG, pem);

  }

  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."
  }
}