Towards Key-Dependent Integral and Impossible Differential Distinguishers on 5-Round AES

Reduced-round AES has been a popular underlying primitive to design new cryptographic schemes and thus its security including distinguishing properties deserves more attention. At Crypto’16, a key-dependent integral distinguisher on 5-round AES was put forward, which opened up a new direction to take more insights into the distinguishing properties of AES. After that, two key-dependent impossible differential (ID) distinguishers on 5-round AES were proposed at FSE’16 and CT-RSA’18, respectively. It is strange that the current key-dependent integral distinguisher requires significantly higher complexities than the key-dependent ID distinguishers, even though they are constructed with the same property of MixColumns (\(2^{128} \gg 2^{98.2}\)). Proposers of the 5-round key-dependent distinguishers claimed that the corresponding integral and ID distinguishers can only work under chosen-ciphertext and chosen-plaintext settings, respectively, which is very different from the situations of traditional key-independent distinguishers.