Abstract
A new method of determining the real number of round cipher transition to indicators of random substitution is proposed. It is based on the accounting of the minimal number only those S-boxes which are used at the first rounds of their transformations and permit to activate all bytes of the latter from the dynamic point of view to the random substitution of cycle transformation. The results of this technique application for evaluation of dynamic indicators of transition to the indicators of random substitution of a number of modern ciphers including the ciphers presented at one time to the Ukrainian competition on the choice of the applicant to the National standard of block cipher.
Highlights
It is acknowledged in cryptographic literature that ciphers asymptotically come to a uniform distribution of differential and linear probabilities (XOR transitions tables of total differentials and linear hulls)
The indicators of cipher security against the attacks of differential and linear cryptanalysis do not depend on the properties, used in S-box ciphers, but are determined by the indicators of appropriate random substitutions, to which ciphers come after a few initial rounds of encryption
The most important conclusion from the results presented consists in our finding the explanation of one of the central ideas of the new developing methodology on cipher coming to random substitution properties after some initial number of encryption rounds despite S-boxes used
Summary
It is acknowledged in cryptographic literature that ciphers asymptotically (with the increase of the number of rounds) come to a uniform distribution of differential and linear probabilities (XOR transitions tables of total differentials and linear hulls). In contrast to the well-known approaches, connecting evaluations of indicators of cipher security against the attacks of differential and linear cryptanalysis accounting the whole number of active S-boxes in cipher, our approach gives the method of determining the real number of cipher round transformations to the indicators of random substitution. It is based on accounting the minimal number of only those active S-boxes which are used at the first rounds of cipher transformation and permit to activate all bytes of its output from the point of view of dynamics of cipher transition to a random substitution of cycle transformation. The method used in this paper is applied for evaluating and comparing dynamic cipher indicators spoken above
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
