Revocable Cryptography from Learning with Errors

TL;DR

This paper introduces quantum cryptographic schemes with key-revocation features based on the learning with errors problem, enabling secure and revocable encryption primitives using quantum states.

Contribution

It presents the first constructions of revocable cryptographic primitives, including encryption and homomorphic encryption, leveraging quantum states and the hardness of learning with errors.

Findings

Successfully constructed revocable encryption schemes

Achieved key-revocation using quantum states

Built upon the learning with errors problem

Abstract

Quantum cryptography leverages many unique features of quantum information in order to construct cryptographic primitives that are oftentimes impossible classically. In this work, we build on the no-cloning principle of quantum mechanics and design cryptographic schemes with key-revocation capabilities. We consider schemes where secret keys are represented as quantum states with the guarantee that, once the secret key is successfully revoked from a user, they no longer have the ability to perform the same functionality as before. We define and construct several fundamental cryptographic primitives with key-revocation capabilities, namely pseudorandom functions, secret-key and public-key encryption, and even fully homomorphic encryption, assuming the quantum subexponential hardness of the learning with errors problem. Central to all our constructions is our approach for making the Dual-Regev encryption scheme (Gentry, Peikert and Vaikuntanathan, STOC 2008) revocable.