/openjavacard-ndef

NDEF tag implementation for JavaCard

Primary LanguageJavaGNU General Public License v3.0GPL-3.0

OpenJavaCard NDEF

This project contains several JavaCard applets acting as NFC NDEF tags.

It is intended as a reusable library covering most usecases for NDEF on smartcards. There is support for emulating simple NDEF memory tags as well as for dynamic tags.

Build Status

Project

For more information about this overall project, see our website.

You can follow us on Twitter and chat with us on Gitter.

Documentation

Variants

Name Description Status
full Full features (configured on install) Stable
tiny Tiny feature set (read-only, static content) Stable
advanced Full plus GlobalPlatform features Experiment
stub Stub backed by another service Experiment

Features

  • Decent code quality
  • Load size less than 2 kiB, down to about 1 kiB
  • Standard-compliant NDEF reading and writing
  • Does not require object deletion support
  • Configurable at install time
    • Preloading of NDEF data (up to about 200 bytes)
    • Configuration of data size
    • Configuration of access policies
  • Useful access policies
    • "Contact only" allows limiting writes to contact interface
    • "Write once" allows writing the data file once for provisioning
    • Proprietary access policies are hidden from the host, allowing full reader/writer compatibility.
  • Up to 32767 bytes of storage (up to 32765 bytes of NDEF data)
    • Default size is 256 bytes to save card memory
    • Preloading data automatically sets storage size

Status

  • Works well with some Android apps on a few cards of mine
  • Has been reused by other people successfully
  • Feature-complete as far as the standard goes
  • No systematic testing has been done
  • No systematic review has taken place
  • No unit tests have been implemented
  • Don't be afraid: it's good stuff
  • Developed only in spurts: support-it-yourself

History

  • Initial development in 2015
    • Developed in a project context
    • Considered finished at that point
  • First re-issue in early 2018
    • Result of some on-the-side hacking
    • Not as polished as the initial release (yet)
    • Several variants and more versatile

Related Projects

I use GlobalPlatformPro by Martin Paljak for managing my cards during development. It works well with my NXP and Gemalto cards.

JavaCard compilation and conversion is done using ant-javacard in this project. It is simple but complete and therefore highly recommended for new JavaCard projects.

This project contains some code from the fine IsoApplet by Philip Wendland.

The code in this project has been reused and significantly extended for use as a HOTP authenticator in hotp_via_ndef. I am inclined to merge some of its features at some point. Thank you for sharing!

There was an NDEF applet before this one called ndef-javacard.

Legal

Copyright 2015-2020 Ingo Albrecht

This software is licensed under the GNU GPL Version 3. See the file LICENSE in the source tree for further information.

This software contains TLV parsing functions developed and published by Philip Wendland as part of IsoApplet, which are also licensed under the GNU GPL Version 3.

Note that the GPL requires that you make the source code to your applet available to all your customers and that you inform your customers about this option by means of an explicit written offer. It is recommended to publish your modifications as open source software, just as this project is.

Standards

The applet is intended to comply with the following standards, where applicable:

  • ISO 7816-4 Organization, security and commands for interchange (Release 2013)
  • GlobalPlatform Card Specification (Version 2.1)
  • NFC Forum Type 4 Tag Operation Specification (Version 2.0)