Towards More Secure PUF Applications: A Low-Area Polar Decoder Implementation
Claus Kestel, Christoph Frisch, Michael Pehl, Norbert Wehn · 2022
Physical unclonable functions (PUFs) are security primitives that rely on random manufacturing variations. In comparison to secure non-volatile memory, PUFs offer the same functionality for storing a cryptographic key but with a lower cost. This makes them especially interesting for systems with limited resources. Deriving a reliable key from a noisy PUF requires an error correction code. In recent years, several works have suggested polar codes for PUFs pointing to security benefits of this code class. However, none of them provided a hardware implementation, which additionally has to match the low-cost nature of PUFs, i.e., very small area. Since polar decoders are more complex compared to other codes like algebraic codes used for PUFs, the practical applicability of polar codes remained uncertain. This work shows for the first time that polar code implementations are well suited for PUFs. Our polar decoder implementation, which is optimized for PUFs, shows a total area of only 4.2k µm2in a 22nm technology.