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YubiKey challenge-response USB and NFC driver for Android
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ykDroid is an Android app that provides an interface for integrating the challenge-response functionality of YubiKeys into other apps. Both USB and NFC (YubiKey NEO required for NFC) are supported on compatible devices.

Get it on Google Play Get it on F-Droid


ykDroid provides an Intent called net.pp3345.ykdroid.intent.action.CHALLENGE_RESPONSE, which accepts an extra byte[] challenge and returns an extra byte[] response. Optionally, an extra String purpose may be passed additionally in the intent to identify the purpose of the challenge. ykDroid will use this identifier to remember and pre-select the slot used for each purpose.

Upon invocation, ykDroid will automatically detect which connection methods (USB and/or NFC) are available and show a dialog overlay with instructions to the user.

Example code:

private static final int CHALLENGE_RESPONSE_REQUEST_CODE = 12345;

private void startChallengeResponse(final byte[] challenge) {
    final Intent intent = new Intent("net.pp3345.ykdroid.intent.action.CHALLENGE_RESPONSE");
    intent.putExtra("challenge", challenge);
    intent.putExtra("purpose", "some-unique-purpose-identifier"); // optional

    startActivityForResult(intent, CHALLENGE_RESPONSE_REQUEST_CODE);

public void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
    if(requestCode == CHALLENGE_RESPONSE_REQUEST_CODE && resultCode == RESULT_OK) {
        final byte[] response = data.getByteArrayExtra("response");
        // ...

Apps that integrate ykDroid

  • Keepass2Android - Password manager app compatible with KeePass
  • ykpass - Password app that derives passwords directly from the YubiKey's response value


PRs welcome! I am open for adding more YubiKey functionality, but bugfixes and additional translations are also very appreciated :-)

Bugs & issues

Please use the GitHub issue tracker for reporting bugs and feature requests.


Yubico and YubiKey are registered trademarks of Yubico. Google Play and the Google Play logo are trademarks of Google LLC.

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