Grain-128PLE: Generic Physical-Layer Encryption for IoT Networks

TL;DR

This paper introduces Grain-128PLE, a lightweight physical layer encryption scheme derived from Grain-128AEAD v2, designed to provide generic data confidentiality for IoT networks by encrypting at the physical layer.

Contribution

It presents a novel placement of a stream cipher at the physical layer, making encryption independent of channel conditions and protocol stack, unlike previous approaches.

Findings

Maintains security strength similar to Grain-128AEAD v2

Enables generic physical layer encryption for IoT

Designed for minimal resource footprint

Abstract

Physical layer security (PLS) encompasses techniques proposed at the physical layer to achieve information security objectives while requiring a minimal resource footprint. The channel coding-based secrecy and signal modulation-based encryption approaches are reliant on certain channel conditions or a certain communications protocol stack to operate on, which prevents them from being a generic solution. This paper presents Grain-128PLE, a lightweight physical layer encryption (PLE) scheme that is derived from the Grain-128AEAD v2 stream cipher. The Grain-128PLE stream cipher performs encryption and decryption at the physical layer, in between the channel coding and signal modulation processes. This placement, like that of the A5 stream cipher that had been used in the GSM communications standard, makes it a generic solution for providing data confidentiality in IoT networks. The design of Grain-128PLE maintains the structure of the main building blocks of the original Grain-128AEAD v2 stream cipher, evaluated for its security strength during NIST's recent Lightweight Cryptography competition, and is therefore expected to achieve similar levels of security.