Hacking Encrypted Wireless Power: Cyber-Security of Dynamic Charging

TL;DR

This paper demonstrates a method to hack frequency-varying wireless power encryption by using an auxiliary coil and adaptive compensation, successfully stealing up to 84% of the energy intended for authorized receivers.

Contribution

It introduces a novel decryption approach for encrypted wireless power transfer that can effectively compromise frequency-hopping energy encryption systems.

Findings

Successfully stole 78-84% of energy from authorized receivers.

Effectively hacked fast frequency-varying encrypted systems.

Validated approach through simulation and experiments.

Abstract

Recently, energy encryption for wireless power transfer has been developed for energy safety, which is important in public places to suppress unauthorized energy extraction. Most techniques vary the frequency so that unauthorized receivers cannot extract energy because of non-resonance. However, this strategy is unreliable. To stimulate the progress of energy encryption technology and point out security holes, this paper proposes a decryption method for the fundamental principle of encrypted frequency-varying wireless power transfer. The paper uses an auxiliary coil to detect the frequency and a switched-capacitor array to adaptively compensate the receiver for a wide frequency range. The switched-capacitor array contains two capacitors and one semi-conductor switch. One capacitor compensates the receiver all the time while the other's active time during one wireless power transfer cycle is regulated by the switch. Thus, the proposed hacking receiver controls the equivalent capacitance of the compensation and steals energy. Finally, a detailed simulation model and experimental results prove the effectiveness of the attack on frequency-hopping energy encryption. Although any nonnegligible energy extracted would be problematic, we achieved to steal 78% to 84% of the energy an authorized receiver could get. When the frequency changes, the interceptor is coarsely tuned very quickly, which can hack fast frequency-varying encrypted system.