Secure Lightweight Entity Authentication with Strong PUFs: Mission Impossible?

Physically unclonable functions (PUFs) exploit the unavoidable manufacturing variations of an integrated circuit (IC). Their input-output behavior serves as a unique IC ‘fingerprint’. Therefore, they have been envisioned as an IC authentication mechanism, in particular for the subclass of so-called strong PUFs. The protocol proposals are typically accompanied with two PUF promises: lightweight and an increased resistance against physical attacks. In this work, we review eight prominent proposals in chronological order: from the original strong PUF proposal to the more complicated converse and slender PUF proposals. The novelty of our work is threefold. First, we employ a unified notation and framework for ease of understanding. Second, we initiate direct comparison between protocols, which has been neglected in each of the proposals. Third, we reveal numerous security and practicality issues. To such an extent, that we cannot support the use of any proposal in its current form. All proposals aim to compensate the lack of cryptographic properties of the strong PUF. However, proper compensation seems to oppose the lightweight objective.