Temperature-Triggered Hardware Trojan Based Algebraic Fault Analysis of SKINNY-64-64 Lightweight Block Cipher

SKINNY-64-64 is a lightweight block cipher with a 64-bit block length and key length, and it is mainly used on the Internet of Things (IoT). Currently, faults can be injected into cryptographic devices by attackers in a variety of ways, but it is still difficult to achieve a precisely located fault attacks at a low cost, whereas a Hardware Trojan (HT) can realize this. Temperature, as a physical quantity incidental to the operation of a cryptographic device, is easily overlooked. In this paper, a temperature-triggered HT (THT) is designed, which, when activated, causes a specific bit of the intermediate state of the SKINNY-64-64 to be flipped. Further, in this paper, a THT-based algebraic fault analysis (THT-AFA) method is proposed. To demonstrate the effectiveness of the method, experiments on algebraic fault analysis (AFA) and THT-AFA have been carried out on SKINNY-64-64. In the THT-AFA for SKINNY-64-64, it is only required to activate the THT 3 times to obtain the master key with a 100% success rate, and the average time for the attack is 64.57 s. However, when performing AFA on this cipher, we provide a relationship between the number of different faults and the residual entropy of the key. In comparison, our proposed THT-AFA method has better performance in terms of attack efficiency. To the best of our knowledge, this is the first HT attack on SKINNY-64-64.