New Representations of the AES Key Schedule

In this paper we present a new representation of the AES key schedule, with some implications to security AES-based schemes. particular, show that AES-128 schedule can be split into four independent parallel computations operating on 32 bits chunks, up linear transformation. Surprisingly, property has not been described in literature after more than 20 years analysis AES. We two consequences our representation, improving previous cryptanalysis results First, observe iterating an odd number rounds function short cycles. This explains observation Khairallah mixFeed, second-round candidate NIST lightweight competition. Our actually shows his forgery attack mixFeed succeeds probability 0.44 (with data complexity 220 GB), breaking scheme practice. The same also leads novel ALE, another AEAD scheme. gives efficient ways combine information from first subkeys and last subkeys, order reconstruct corresponding master keys. particular improve impossible differential attacks against AES-128.