RadKey: An LLM-Guided RF Backscatter System for Through-Wall Keystroke Inference

In today's digitally connected world, keyboards remain the primary interface for inputting sensitive information, making them a persistent target for eavesdropping attacks. While prior keystroke inference techniques have exploited side-channel signals such as acoustics and vibrations, they...

RadEar: A Self-Supervised RF Backscatter System for Voice Eavesdropping and Separation

Eavesdropping on voice conversations presents a growing threat to personal privacy and information security. In this paper, we present RadEar, a novel RF backscatter-based system designed to enable covert voice eavesdropping through walls. RadEar consists of two key components: i a batteryless RF...

ShieldBypass: On the Persistence of Impedance Leakage beyond EM Shielding

Electromagnetic EM shielding is widely used to suppress radiated emissions and limit passive EM side-channel leakage. However, shielding does not address active probing, where an adversary injects external radio-frequency RF signals and observes the device's reflective response. This work studies...

AmbShield: Enhancing Physical Layer Security with Ambient Backscatter Devices against Eavesdroppers

Passive eavesdropping compromises confidentiality in wireless networks, especially in resource-constrained environments where heavyweight cryptography is impractical. Physical layer security PLS exploits channel randomness and spatial selectivity to confine information to an intended receiver wit...

Eavesdropping Risk in Terahertz Channels by Covered Wavy Surfaces

Terahertz communications offer unprecedented data rates for next-generation wireless networks but suffer blockage susceptibility that restrict coverage and introduce physical-layer security vulnerabilities. Non-line-of-sight relay schemes using metallic wavy surfaces MWS address coverage...

Backscatter Device-Aided Integrated Sensing and Communication: a Pareto Optimization Framework

Integrated sensing and communication ISAC systems potentially encounter significant performance degradation in densely obstructed urban and non-line-of-sight scenarios, thus limiting their effectiveness in practical deployments. To deal with these challenges, this paper proposes a backscatter...

Physical Layer Challenge-Response Authentication between Ambient Backscatter Devices

Ambient backscatter communication AmBC has become an integral part of ubiquitous Internet of Things IoT applications due to its energy-harvesting capabilities and ultra-low-power consumption. However, the open wireless environment exposes AmBC systems to various attacks, and existing authenticati...

The Trip to ZigBee Backscatter across a Decade, a Systematic Review

The field of backscatter communication has undergone a profound transformation, evolving from a niche technology for radio-frequency identification RFID into a sophisticated paradigm poised to enable a truly battery-free Internet of Things IoT. This evolution is built upon a deepening understandi...