International Association
for Cryptologic Research

We demonstrate how to build computationally secure commitment schemes with the aid of quantum auxiliary inputs without unproven complexity assumptions. Furthermore, the quantum auxiliary input can be prepared either (1) efficiently through a trusted setup similar to the classical common random string model, or (2) strictly between the two involved parties in uniform exponential time. Classically this remains impossible without first proving $\mathsf{P} \neq \mathsf{NP}$.