Key Agreement and Oblivious Transfer from Free-Energy Limitations

TL;DR

This paper introduces cryptographic protocols for key agreement and oblivious transfer based on thermodynamic principles, specifically Landauer's limit, exploring the fundamental physical limits of computation and security.

Contribution

It presents the first protocols whose security is grounded in the second law of thermodynamics, linking physical laws to cryptographic security.

Findings

Protocols are secure under the assumption of limited free energy access.

Results extend to quantum computing scenarios.

Protocols highlight the physical limits of reversible computation.

Abstract

We propose one of the very few constructive consequences of the second law of thermodynamics. More specifically, we present protocols for secret-key establishment and multiparty computation the security of which is based fundamentally on Landauer's principle. The latter states that the erasure cost of each bit of information is at least kTln2 (where k is Boltzmann's constant and T is the absolute temperature of the environment). Albeit impractical, our protocols explore the limits of reversible computation, and the only assumption about the adversary is her inability to access a quantity of free energy that is exponential in the one of the honest participants. Our results generalize to the quantum realm.