Paper 2005/440

HB++: a Lightweight Authentication Protocol Secure against Some Attacks

Julien Bringer, Hervé Chabanne, and Emmanuelle Dottax

Abstract

At Crypto'05, Juels and Weis introduce HB+, an enhancement of the Hopper and Blum (HB) authentication protocol. This protocol HB+ is proven secure against active attacks, though preserving HB's advantages: mainly, requiring so few resources to run that it can be implemented on an RFID tag. However, in a wider adversarial model, Gilbert, Robshaw and Sibert exhibit a very effective attack against HB+. We here show how a modification of the HB+ protocol thwarts Gilbert et al's attack. The resulting protocol, HB++, remains a good candidate for RFID tags authentication.