Device owner using NFC on Android Lollipop

DeviceOwnerWriteActivity.java

MessageDigest digest = null;
try {
    digest = MessageDigest.getInstance("SHA-1");
} catch (NoSuchAlgorithmException e) {
    e.printStackTrace();
}

byte[] apkBytes = new byte[0];
try {
    apkBytes = IOUtils.toByteArray(getAssets().open("app-debug.apk"));
} catch (IOException e) {
    e.printStackTrace();
}

digest.update(apkBytes);

NfcAdapter defaultAdapter = NfcAdapter.getDefaultAdapter(this);
try {
    Properties p = new Properties();
    p.setProperty(DevicePolicyManager.EXTRA_PROVISIONING_DEVICE_ADMIN_PACKAGE_NAME, "com.manijshrestha.lollipopkiosk");
    p.setProperty(DevicePolicyManager.EXTRA_PROVISIONING_DEVICE_ADMIN_PACKAGE_DOWNLOAD_LOCATION, "https://www.dropbox.com/s/8o3soifag7g84ls/app-debug.apk?dl=1");
    p.setProperty(DevicePolicyManager.EXTRA_PROVISIONING_DEVICE_ADMIN_PACKAGE_CHECKSUM, Base64.encodeToString(digest.digest(), Base64.URL_SAFE));

    StringWriter stringWriter = new StringWriter();
    p.store(stringWriter, "");

    NdefMessage msg = new NdefMessage(NdefRecord.createMime(DevicePolicyManager.MIME_TYPE_PROVISIONING_NFC, stringWriter.toString().getBytes("UTF-8")));
    defaultAdapter.setNdefPushMessage(msg, this);
} catch (Exception e) {
    throw new RuntimeException(e);
}