Open AccessProvable Security Against a Differential Attack
Author(s) -
Kaisa Nyberg,
Lars R. Knudsen
Publication year - 1994
Publication title -
daimi pb
Language(s) - English
Resource type - Journals
eISSN - 2245-9316
pISSN - 0105-8517
DOI - 10.7146/dpb.v23i473.6946
Subject(s) - differential cryptanalysis , block cipher , mathematics , linear cryptanalysis , upper and lower bounds , iterated function , cipher , stream cipher , discrete mathematics , slide attack , combinatorics , algorithm , computer science , cryptography , encryption , computer security , mathematical analysis
The purpose of this paper is to show that there exist DES-like iterated ciphers, which are provably resistant against differential attacks. The main result on the security of a DES-like cipher with independent round keys is Theorem 1, which gives an upper bound to the probability of s -round differentials, as defined in Markov Ciphers and Differential Cryptanalysis by X. Lai et al. and this upper bound depends only on the round function of the iterated cipher. Moreover, it is shown that there exist functions such that the probabilities of differentials are less than or equal to 2 3-n , where n is the length of the plaintext block. We also show a prototype of an iterated block cipher, which is compatible with DES and has proven security against differential attacks.