A New Distinguisher for CubeHash-8/b and CubeHash-15/b Compression Functions
CubeHash is one of the round 2 candidates of the public SHA-3 competition hosted by NIST. It was designed by Bernstein. In this paper we find a new distinguisher to distinguish CubeHash compression function from a random function. This distinguisher principle is based on rotational analysis that formally introduced by Khovratovich and Nikolic. In order to use this technique, we need to compute the probability that four swap functions in CubeHash round function preserve the rotational property for any input pair. We compute these probabilities and find a new distinguisher that distinguish CubeHash-8/b and CubeHash-15/b compression function from a random function with probability greater than and , respectively. Until we know this is the first distinguisher for CubeHash compression function with more than 14 rounds.
Keywords: SHA-3 candidate, CubeHash, rotational analysis, distinguisher.
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ABOUT THE AUTHORS
Javad Alizadeh
Javad Alizadeh received the Bachelor\'s degree in Applied Mathematics with the honor degree from IHU, Tehran, Iran in 2007 and Master\'s degree in Telecommunication in the field of Cryptography with the honor degree from IHU, Tehran, Iran in 2010. He was chosen as a superior researcher student of IHU, in 2010. Currently, he is a researcher in the field of cryptography and teacher assistant (TA) at the faculty and research center of communication and information technology, IHU, Tehran, Iran. His research interest includes: Cryptography, Cryptanalysis, Information Systems Security, Mathematics of Cryptography. He is a member of ISC.
Abdolrasoul Mirghadri
Abdolrasoul Mirghadri received the B.Sc., M.Sc. and PHD degrees in Mathematical Statistics, from the faculty of Science, Shiraz University in 1986, 1989 and 2001, respectively. He is an assistant professor at the faculty and research center of communication and information technology, IHU, Tehran, Iran since 1989. His research interest includes: Cryptography, Cryptanalysis, Statistics and Stochastic Processes. He is a member of ISC, ISS and IMS.
Javad Alizadeh
Javad Alizadeh received the Bachelor\'s degree in Applied Mathematics with the honor degree from IHU, Tehran, Iran in 2007 and Master\'s degree in Telecommunication in the field of Cryptography with the honor degree from IHU, Tehran, Iran in 2010. He was chosen as a superior researcher student of IHU, in 2010. Currently, he is a researcher in the field of cryptography and teacher assistant (TA) at the faculty and research center of communication and information technology, IHU, Tehran, Iran. His research interest includes: Cryptography, Cryptanalysis, Information Systems Security, Mathematics of Cryptography. He is a member of ISC.
Abdolrasoul Mirghadri
Abdolrasoul Mirghadri received the B.Sc., M.Sc. and PHD degrees in Mathematical Statistics, from the faculty of Science, Shiraz University in 1986, 1989 and 2001, respectively. He is an assistant professor at the faculty and research center of communication and information technology, IHU, Tehran, Iran since 1989. His research interest includes: Cryptography, Cryptanalysis, Statistics and Stochastic Processes. He is a member of ISC, ISS and IMS.
