New Key Recovery Attack on Reduced-Round AES

A new fundamental 4-round property of AES, called the zero-difference property, was introduced by Rønjom, Bardeh and Helleseth at Asiacrypt 2017. Our work characterizes it in a simple way by exploiting the notion of related differences which was introduced and well analyzed by the AES designers. We extend the 4-round property by considering some further properties of related differences over the AES linear layer, generalizing the zero-difference property. This results in a new key-recovery attack on 7-round AES which is the first attack on 7-round AES by exploiting the zero-difference property.