We've been working closely with some customers over time regarding the possibility to use the Yubikey in access control systems and other RFID/NFC projects, thereby combining functionality of "digital" and "physical" access.
We have therefore developed Yubikey with RFID and have selected MIFARE Classic as the first supported standard. We are highly aware of the shortcomings of MIFARE Classic, but given its large installed base the choice is simple. We can with short lead time also support Ultralight, DESFire and Plus versions, thereby offering the security level that fits a particular application. We may also consider other 13.56 MHz RFID standards (HF).
The Yubikey RFID looks exactly as an ordinary Yubikey 2 and offers a reading distance of about 2-4 centimeters (approx one inch), depending on the reader antenna geometry.
The Yubikey RFID is not yet a stock product but we have pre-production samples ready. Depending on the outcome of some upcoming pilot projects and customer requests for various RFID standards, the plan is to have Yubikey RFID ready for mass deployment during the first quarter of 2010. Final price is not set but will be about 2-3 USD extra (compared with a standard Yubikey) in 10k volumes.
We have not yet made Yubikey RFID available through the web store, but If you have a specific integrated access control project in mind, please write me a few lines about your needs and plans and we can then send a Yubikey RFID for evaluation. My e-mail is jakob at yubico dot com.http://www.yubico.com/news/091130/
With the best regards,
Hardware- and firmware guy @ Yubico