Stealthy Hardware Trojan Based Algebraic Fault Analysis of HIGHT Block Cipher

Abstract

HIGHT is a lightweight block cipher which has been adopted as a standard block cipher. In this paper, we present a bit-level algebraic fault analysis (AFA) of HIGHT, where the faults are perturbed by a stealthy HT. The fault model in our attack assumes that the adversary is able to insert a HT that flips a specific bit of a certain intermediate word of the cipher once the HT is activated. The HT is realized by merely 4 registers and with an extremely low activation rate of about 0.000025. We show that the optimal location for inserting the designed HT can be efficiently determined by AFA in advance. Finally, a method is proposed to represent the cipher and the injected faults with a merged set of algebraic equations and the master key can be recovered by solving the merged equation system with an SAT solver. Our attack, which fully recovers the secret master key of the cipher in 12572.26 seconds, requires three times of activation on the designed HT. To the best of our knowledge, this is the first Trojan attack on HIGHT.

Hardware Trojan detection for lightweight ciphers implemented on field‐programmable gate arrays using the replay algorithm

“…Therefore, it is practically impossible to activate such sequential HT during functional testing. Such challenge was also noted in Chen et al 38 and Wang et al 39 and signifies the importance of detecting this type of HTs. If the HT causes one bit of the key to be leaked, then the entire key requires 64 HT activations.…”

“…Untrusted third‐party might insert an HT in the IP. Electronic design automation (EDA) tools. An infected EDA tool could insert an HT by modifying the logic in the pre‐place, post‐place, or route netlists 38 A rogue employee in the chip development team. …”

“…The attack model in this research is illustrated in Figure 2. The model assumes a complex sequential HT, similar to the one described by Chen et al 38 Compared with combinational HTs, sequential HTs are harder to detect and present a tougher security challenge. Figure 2 illustrates the following model components: The cipher design which implements the cipher algorithm.…”

“…For example, the attacker can construct an equation system for the correct cipher behavior and the modified cipher behavior. Then, the equation system and the cipher output are fed into automatic solver to recover the key 38 …”

Hardware Security in IoT Devices with Emphasis on Hardware Trojans

“…Reference [33] presents HT-based algebraic fault analysis (AFA) of a lightweight block cipher HIGHT. HIGHT is one of the lightweight encryption algorithms that is considered for implementation in an IoT.…”