The Conflicted Usage of RLUTs for Security-Critical Applications on FPGA

Abstract

Modern field programmable gate arrays (FPGAs) have evolved significantly in recent years and have found applications in various fields like cryptography, defense, aerospace, and many more. The integration of FPGA with highly efficient modules like DSP and block RAMs has increased the performance of FPGA significantly. This paper addresses the lesser explored feature of modern FPGA called as reconfigurable LUT (RLUT) whose content can be updated internally, even during runtime. We describe the basic functionality of RLUT and discuss its potential applications for security from both destructive and constructive point of view, highlighting the conflicted usage of RLUTs. Several use cases exploiting RLUT feature in security-critical scenarios (physical attacks related in particular) are studied in detail. The paper proposes design of stealthy hardware Trojans having zero payload overhead to highlight destructive applications which can be built using hardware Trojans. On the other hand, this paper also highlights several constructive applications based on RLUT features, starting from lightweight side-channel countermeasures to kill switch to prevent the FPGA hardware from environmental hazards and malicious attack attempts.

Secure VLSI Design: Countermeasures against Hardware Trojans and Side-Channel Attacks

“…Hardware Trojans and side-channel attacks can damage critical operations and cryptographic keys; hence, secure hardware modules like TEEs and enclaves are essential. Critical computations and cryptographic activities are executed securely in the IC architecture using these trusted hardware modules, assuring data confidentiality, integrity, and authenticity (Roy et al, 2018). ICs with physically unclonable functions (PUFs) and true random number generators (TRNGs) improve cryptographic operations and authentication procedures.…”

Secure Programming with SAS: Mitigating Risks and Protecting Data Integrity

“…Log security events and suspected activity for forensic investigation and incident response. Review audit logs and system operations regularly for data breaches and unauthorized reviewed d access (Roy et al, 2018).…”

Trojan Awakener: Detecting Dormant Malicious Hardware Using Laser Logic State Imaging

“…Therefore, malicious modifications of the design, referred to as hardware Trojans (HTs), endanger the security of many applications. On FPGAs, a Trojan might be inserted after manufacturing and testing, i.e., in the untrusted field [1], [2], for instance, by altering the entire configuration (known as bitstream) or via partial reconfiguration. Particularly if the chip foundry can be trusted, this depicts a much more powerful threat model than for ASICs.…”

“…They show that on an FPGA, longer signal paths can be realized by instantiating route-thru LUTs, or by modifying the routing in the switch boxes, which results in zero overhead in resource usage, and therefore, is hard to detect. In another effort, Roy et al showed that the reconfigurable LUTs could be exploited to realize HTs with zero payload overheads [2]. Finally, Ng et al demonstrated that integrated sensors inside FPGAs could be deployed as Trojan triggers [1].…”