Paper 2023/222

A Lightweight Identification Protocol Based on Lattices

Abstract

In this work we present a lightweight lattice-based identification protocol based on the CPA-secured public key encryption scheme Kyber. It is designed as a replacement for existing classical ECC- or RSA-based identification protocols in IoT, smart card applications, or for device authentication. The proposed protocol is simple, efficient, and implementations are supposed to be easy to harden against side-channel attacks. Compared to standard constructions for identification protocols based on lattice-based KEMs, our construction achieves this by avoiding the Fujisaki-Okamoto transform and its impact on implementation security. Moreover, contrary to prior lattice-based identification protocols or standard constructions using signatures, our work does not require rejection sampling and can use more efficient parameters than signature schemes. We provide a generic construction from CPA-secured public key encryption schemes to identification protocols and give a security proof of the protocol in the ROM. Moreover, we instantiate the generic construction with Kyber, for which we use the proposed parameter sets for NIST security levels I, III, and V. To show that the protocol is suitable for constrained devices, we implemented one selected parameter set on an ARM Cortex-M4 microcontroller. As the protocol is based on existing algorithms for Kyber, we make use of existing SW components (e.g., fast NTT implementations) for our implementation.