Exploiting safe error based leakage of RFID authentication protocol using hardware Trojan horse

Radio-Frequency Identification tags are used for several applications requiring authentication mechanisms, which if subverted can lead to dire consequences. Many of these devices are based on low-cost Integrated Circuits which are designed in off-shore fabrication facilities, raising concerns about their trust. Recently, a lightweight entity authentication protocol called LCMQ was proposed, which is based on Learning Parity with Noise, Circulant Matrix, and Multivariate Quadratic problems. This protocol was proven to be secure against Man-in-the-middle attack and cipher-text only attacks. In this paper, we show that in the standard setting, although the authentication uses two m bit keys, Ki and K2, knowledge of only K2 is sufficient to forge the authentication. Based on this observation, we design a stealthy malicious modification to the circuitry based on the idea of Safe-Errors to leak K2 which can be henceforth used to forge the entire authentication mechanism. We develop an extremely lightweight Field Programmable Gate Array prototype of the design. The malicious modification is implemented using only four Lookup Tables which leads to insignificant increase in the power, time and slice registers overhead.