Physically Unclonable Functions (PUFs) in silicon have received significant attention since their initial proposal, with a wide variety of different designs available. This is largely due to their ability to provide device-specific outputs which can be used in diverse applications such as authentication, attestation, and cryptographic key generation. Existing designs for silicon PUFs are based on exploiting manufacturing variation in delay lines or the behaviour of memory cells to provide device-unique outputs. This paper proposes a new kind of PUF which we refer to as a Gate Tunnelling PUF. Our PUF design exploits the effect of manufacturing variation on quantum gate tunnelling current to generate unique, reproducible, yet unpredictable PUF outputs. A significant benefit of our design is its realisability in standard CMOS technology, leading to easy integration of our Gate Tunnelling PUF with other security and general system functions in single-chip designs. We have prototyped our Gate Tunnelling PUF design, producing test devices in arrays of 3584 output bits. Initial results are very promising, showing good randomness, uniqueness, reproducibility and temperature stability. These properties suggest that our devices’ outputs require minimal post-processing to be used for cryptographic keys.

Abstract The Learning with Errors (LWE) problem is the fundamental backbone of modern lattice-based cryptography, allowing one to establish cryptography on the hardness of well-studied computational problems. However, schemes based on LWE are often impractical, so Ring LWE was introduced as a form of ‘structured’ LWE, trading off a hard to quantify loss of security for an increase in efficiency by working over a well-chosen ring. Another popular variant, Module LWE, generalizes this exchange by implementing a module structure over a ring. In this work, we introduce a novel variant of LWE over cyclic algebras (CLWE) to replicate the addition of the ring structure taking LWE to Ring LWE by adding cyclic structure to Module LWE. We show that the security reductions expected for an LWE problem hold, namely a reduction from certain structured lattice problems to the hardness of the decision variant of the CLWE problem (under the condition of constant rank d). As a contribution of theoretic interest, we view CLWE as the first variant of Ring LWE which supports non-commutative multiplication operations. This ring structure compares favorably with Module LWE, and naturally allows a larger message space for error correction coding.