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.

翻译：物理层安全（PLS）涵盖在物理层提出的技术手段，旨在以最小资源开销实现信息安全目标。基于信道编码的保密技术与基于信号调制的加密方法需要特定信道条件或特定通信协议栈的支持，因此无法作为通用解决方案。本文提出Grain-128PLE——一种轻量级物理层加密（PLE）方案，该方案源自Grain-128AEAD v2流密码。Grain-128PLE流密码在物理层的信道编码与信号调制过程之间执行加解密操作。这种部署位置使其成为物联网网络中提供数据机密性的通用解决方案，类似于曾在GSM通信标准中使用的A5流密码。Grain-128PLE的设计保留了原始Grain-128AEAD v2流密码核心模块的结构——该密码在NIST近期举办的轻量级密码竞赛中已通过安全强度评估，因此预期可实现同等级别的安全性。