Powerful Primitives in the Bounded Quantum Storage Model

TL;DR

This paper introduces information-theoretic secure cryptographic primitives in the bounded quantum storage model, enabling security against adversaries with large quantum memories without requiring quantum memory for honest users.

Contribution

It provides novel constructions of secure primitives in the bounded quantum storage model, including symmetric and asymmetric encryption, signatures, and programs, with security scaling to large quantum memories.

Findings

Secure symmetric key encryption and MACs with no quantum memory for honest users.

Asymmetric encryption and signatures secure against large quantum memories.

All schemes satisfy disappearing security, preventing storage and later use.

Abstract

The bounded quantum storage model aims to achieve security against computationally unbounded adversaries that are restricted only with respect to their quantum memories. In this work, we provide information-theoretic secure constructions in this model for the following powerful primitives: (1) CCA1-secure symmetric key encryption, message authentication codes, and one-time programs. These schemes require no quantum memory for the honest user, while they can be made secure against adversaries with arbitrarily large memories by increasing the transmission length sufficiently. (2) CCA1-secure asymmetric key encryption, encryption tokens, signatures, signature tokens, and program broadcast. These schemes are secure against adversaries with roughly $e^{\sqrt{m}}$ quantum memory where $m$ is the quantum memory required for the honest user. All of the constructions additionally satisfy disappearing security, essentially preventing an adversary from storing and using a transmission later on.