Efficient Construction of Quantum Physical Unclonable Functions with Unitary t-designs

Quantum physical unclonable functions, or QPUFs, are rapidly emerging as theoretical hardware solutions to provide secure cryptographic functionalities such as key-exchange, message authentication, entity identification among others. Recent works have shown that in order to provide provable security of these solutions against any quantum polynomial time adversary, QPUFs are required to be a unitary sampled uniformly randomly from the Haar measure. This however is known to require an exponential amount of resources. In this work, we propose an efficient construction of these devices using unitary t-designs, called QPUF_t. Along the way, we modify the existing security definitions of QPUFs to include efficient constructions and showcase that QPUF_t still retains the provable security guarantees against a bounded quantum polynomial adversary with t-query access to the device. This also provides the first use case of unitary t-design construction for arbitrary t, as opposed to previous applications of t-designs where usually a few (relatively low) values of t are known to be useful for performing some task. We study the noise-resilience of QPUF_t against specific types of noise, unitary noise, and show that some resilience can be achieved particularly when the error rates affecting individual qubits become smaller as the system size increases. To make the noise-resilience more realistic and meaningful, we conclude that some notion of error mitigation or correction should be introduced.