Revisiting Persistent Fault Analysis: Assessing Weak Keys and Strong Keys in GIFT-64 Lightweight Cipher
2020
In this paper, we propose to pinpoint classes of weak and strong keys in GIFT-64 block cipher when the last round key in the encryption algorithm is subjected to Persistent Fault Analysis (PFA). We observe that ease of mounting PFA on GIFT-64 cipher hardens if the minimum and second minimum probability of occurrence, of Sbox output nibbles, are comparatively closer after a fault is injected, which results in an imbalanced Sbox. This leads to a non-uniform distribution of Sbox output values for a large number of queries made to the cipher. In addition, we also demonstrate that the Hamming weight profile of the master key has a bearance on the average number of queries to the cipher when specific entries in Sbox Lookup Table (LUT) implementation are modified under persistent fault.