Provable Security Against Differential Cryptanalysis

Provable Security for the Skipjack-like Structure against Differential Cryptanalysis and Linear Cryptanalysis

“…Since the Skipjack-like structure can be regarded as one of the generalizations of the Feistel structure in a way, provable security against LC is also obtained as in [12,16,17]. 4 where q is the maximal average linear hull probability of a round function.…”

“…Since the method of calculating linear hull probabilities can be calculated with the reverse order of the method of calculating differential probabilities [12,16,17], we will only consider the differential probabilities in this paper.…”

“…K.Nyberg and R.Knudsen showed that the r-round differential(or linear hull) probabilities in the Feistel structure are bounded by 2p 2 if the maximal differential(or linear hull) probability of round function is p and r ≥ 4 [16]. Furthermore, the probability can be reduced to p 2 if the round function is bijective and r ≥ 3 [1].…”

“…The r-round(r ≥ 15) differential probabilities are bounded by p 4 if the maximal differential probability of the round function is p. Since the proof of linear hull probabilities in LC is almost same as that of differential probabilities [12,16,17], we will just prove the upper bound of differential probabilities of the structure. Furthermore we will show that there does not exists an impossible differential if r ≥ 16 in the generalized Feistel structure and Skipjack-like structure.…”

On Feistel Ciphers Using Optimal Diffusion Mappings Across Multiple Rounds

“…The main advantage of the Feistel structure is its involution property, which provides flexible designs of the underlying F-functions. During the 30 year history of modern block ciphers, extensive studies have been made on Feistel structure [8,11,14]. Currently, many well-known block ciphers, e.g.…”