Tree-based HB protocols for privacy-preserving authentication of RFID tags

An RFID reader must authenticate its designated tags in order to prevent tag forgery and counterfeiting. At the same time, due to privacy requirements of many applications, a tag should remain anonymous and untraceable to an adversary during the authentication process. In this paper, we propose an "HB-like" protocol for privacy-preserving authentication of RFID tags. Previous protocols for privacy-preserving authentication were based on PRF computations. Our protocol can instead be used on low-cost tags that may be incapable of computing traditional PRFs. Moreover, since the underlying computations in HB protocols are very efficient, our protocol also reduces reader-side load compared to PRF-based protocols. We suggest a tree-based approach that replaces the PRF-based authentication from prior work with a procedure such as HB+ or HB#. We optimize the tree-traversal stage through usage of a "light version" of the underlying protocol and shared random challenges across all levels of the tree. This provides significant reduction of the communication resources, resulting in a privacy-preserving protocol almost as efficient as the underlying HB+ or HB#. We also present analytical and simulation results comparing our method with prior proposals in terms of computation, communication and memory overheads. © 2011 IOS Press and the authors. All rights reserved.