After some time of development together with customers, we now officially launch the OATH-HOTP enabled Yubikey.
The 2.1 firmware supports event-based HOTP in accordance with RFC 4226 with a selectable trunction length of 6 or 8 digits. Optionally, a identity can be generated in accordance with the openauthentication.org Token Identifier Specification.
The 2.1 firmware is backwards-compatible with existing firmware versions. The OATH mode is selectable per configuration which allows the Yubikey to have both Yubico OTP and OATH-HOTP in the same physical device.
At present, we do not have OATH support in our validation server. We've set up a Google Code project at
http://code.google.com/p/mod-authn-otp/ The 2.1 Yubikey can be ordered via our webstore at
http://www.yubico.com . We have also added some nice end-of-the-year special volume discounts.
With the best regards,
JakobE
Hardware- and firmware guy @ Yubico