Artificial Signal Injection and Superposition: A Novel Physical Layer Security Framework with Practical Implementation

This paper introduces a revolutionary physical layer security paradigm: Artificial Signal Injection and Superposition (ASIS), a novel framework that actively injects carefully designed artificial signals into the communication channel, creating a superposition with legitimate user data to achieve unprecedented security guarantees. Unlike traditional physical layer security methods that rely on passive channel characteristics, ASIS actively engineers the signal space to create controlled interference that benefits legitimate receivers while confounding eavesdroppers. Our approach leverages multi-dimensional signal processing, game-theoretic optimization, and information-theoretic principles to design injection signals that are: (1) decodable by intended receivers using advanced signal separation techniques, (2) indistinguishable from noise or interference to unauthorized listeners, and (3) adaptive to channel conditions and eavesdropper capabilities. The ASIS framework provides provable security against both passive and active attacks, achieves informationtheoretic secrecy rates, and can be implemented using existing wireless hardware with firmware upgrades. Experimental results from our software-defined radio testbed demonstrate 40 dB SNR advantage for legitimate receivers over eavesdroppers, bit error rates below 10 −6 for legitimate users versus > 0.4 for eavesdroppers, and throughput improvements of 15-30% compared to conventional cryptographic approaches due to reduced overhead. The proposed system represents a paradigm shift in secure communications, moving from passive protection to active signal-space engineering for security.