Welcome to the resource topic for 2009/405
Title:
Generic Attacks on Misty Schemes -5 rounds is not enough-
Authors: Valerie Nachef, Jacques Patarin, Joana Treger
Abstract:Misty schemes are classic cryptographic schemes used to construct pseudo-random permutations from 2n bits to 2n bits by using d pseudo-random permutations from n bits to n bits. These d permutations will be called the internal'' permutations, and $d$ is the number of rounds of the Misty scheme. Misty schemes are important from a practical point of view since for example, the Kasumi algorithm based on Misty schemes has been adopted as the standard blockcipher in the third generation mobile systems. In this paper we describe the best known generic’’ attacks on Misty schemes, i.e. attacks when the internal permutations do not have special properties, or are randomly chosen. We describe known plaintext attacks (KPA), non-adaptive chosen plaintext attacks (CPA-1) and adaptive chosen plaintext and ciphertext attacks (CPCA-2) against these schemes. Some of these attacks were previously known, some are new. One important result of this paper is that we will show that when d=5 rounds, there exist such attacks with a complexity strictly less than 2^{2n}. Consequently, at least 6 rounds are necessary to avoid these generic attacks on Misty schemes. When d \geq 6 we also describe some attacks on Misty generators, i.e. attacks where more than one Misty permutation is required.
ePrint: https://eprint.iacr.org/2009/405
See all topics related to this paper.
Feel free to post resources that are related to this paper below.
Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.
For more information, see the rules for Resource Topics .