https://github.com/Toporin/SatoChipApplet - Open source javacard applet implementing a Bitcoin hardware wallet with full BIP32 support
https://github.com/Yubico/ykneo-openpgp - OpenPGP applet for the YubiKey NEO
https://sourceforge.net/projects/javacardopenpgp/ - Java Card implementation of the OpenPGP card