@inproceedings{c6c3296f09d7432fb5e5cb198f70748c,

title = "Rotational cryptanalysis of ARX revisited",

abstract = "Rotational cryptanalysis is a probabilistic attack applicable to word oriented designs that use (almost) rotation-invariant constants. It is believed that the success probability of rotational cryptanalysis against ciphers and functions based on modular additions, rotations and XORs, can be computed only by counting the number of additions. We show that this simple formula is incorrect due to the invalid Markov cipher assumption used for computing the probability. More precisely, we show that chained modular additions used in ARX ciphers do not form a Markov chain with regards to rotational analysis, thus the rotational probability cannot be computed as a simple product of rotational probabilities of individual modular additions. We provide a precise value of the probability of such chains and give a new algorithm for computing the rotational probability of ARX ciphers. We use the algorithm to correct the rotational attacks on BLAKE2 and to provide valid rotational attacks against the simplified version of Skein.",

keywords = "BLAKE2, Markov chain, Markov cipher, rotational cryptanalysis, Skein",

author = "Dmitry Khovratovich and Ivica Nikoli{\'c} and Josef Pieprzyk and Przemys{\l}aw Soko{\l}owski and Ron Steinfeld",

year = "2015",

doi = "10.1007/978-3-662-48116-5_25",

language = "English",

isbn = "9783662481158",

series = "Lecture Notes in Computer Science",

publisher = "Springer, Springer Nature",

pages = "519--536",

editor = "Gregor Leander",

booktitle = "Fast software encryption",

address = "United States",

note = "22nd International Workshop on Fast Software Encryption, FSE 2015 ; Conference date: 08-03-2015 Through 11-03-2015",

}