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Showing 2 results for Collision
Zahra Zolfaghari, Nasour Bagheri,
Volume 6, Issue 1 (9-2017)
Abstract
In this article, we introduce Time Memory Trade Off attack and a method for finding near collisions in a hash function. By considering hash computations, it is easy to compute a lower bound for the complexity of near-collision algorithms, and to construct matching algorithm. However, this algorithm needs a lot of memory, and uses memory accesses. Recently, some algorithms have been proposed that do not require this amount of memory. They need more hash evaluation, but this attack is actually more practical. These algorithms can be divided in two main group: the first group is based on truncation and the second group is based on covering codes. In this paper, we consider the first group that is based on truncation. For practical implementation, it can be assumed that some memory is available, Leurent [10] showed that it is possible to reduce the complexity significantly by using this memory. In the next step, Sasaki et al. [9] proposed improvement of most popular Time Memory Trade off for K-tree algorithm by using multi-collision based on Helman’s table. As a result, they obtained new trade off curve that for k=4 the tradeoff curve will be . In this article, at the first the methods of TMTO, and then the method of finding near-collision by using TMTO are explained.
Akram Khalesi, Mohammad Ali Orumiehchiha,
Volume 9, Issue 1 (8-2020)
Abstract
Sponge structure is a structure widely used in the design of cryptographic algorithms that reduces the design of the algorithms to the design of a permutation or pseudo-random function. The development of sponge-based algorithms and the selection of designs based on this structure in SHA3 and CAESAR competitions increase the need to examine its security against various types of attacks. In the previous article, we defined and examined the features of this structure, and in this article, with the focus on the security of sponge structures, we study general analysis methods on this structure and examine their complexities. Considering the complexities introduced for the general attacks, it is necessary to achieve a certain level of security, and therefore this article, both in terms of design and cryptanalysis of sponge-based algorithms plays important role. It is suggested that the article "Sponge structure; introduction and applications" published in this journal be reviewed before reading this article.
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