An efficient authentication protocol for RFID systems resistant to active attacks

RFID technology is a ubiquitous technology, and seems destined to become more a more ubiquitous. Traditional cryptographic primitives are not supported on low-cost RFID tags since, at most, 4K gates can be devoted to security-related tasks. Despite this, there are a vast number of proposals based on the use of classical hash functions, an assumption that is not realistic (at least at the present time). Furthermore, none of the published authentication protocols are resistant to active attacks. We try to address these two issues in this work by designing a new authentication protocol, secure against passive and active attacks, inspired by Shieh et al.'s protocol for smart-cards, but adapted to RFID systems. The original Shieh et al.'s scheme is considered one of the most secure an efficient protocols in the smart-card field. Because in this protocol tags should support a hash-function on-board, a new lightweight hash function, named Tav-128, is also proposed. A preliminary security analysis is shown, as well as a study on its hardware complexity, which concludes that its implementation is possible with around 2.6K gates.