Seminar

**MATHEMATICAL FOUNDATIONS OF INFORMATICS
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The next meeting of the seminar will be held on **July 4, 2019**, at **3.00 p.m.** in Room **503** of IMI-BAS.

A talk on:

## Rotation cryptanalysis on Chaskey

will be delivered by **Liliya Kraleva, Catholic University of Leuven.**

**Abstract**. Rotational cryptanalysis is a probabilistic technique mainly used over ARX cryptographic structures. After encryption, if the outputs also form a rotational pair with probability more than for a random permutation we can use that as a distinguisher. Chaskey is a lightweight MAC algorithm for 32-bit microcontrollers. Its underlying block cipher has a permutation using only XOR, rotation and modular addition as operations. We perform a related key attack over Chaskey and find a distinguisher by using rotational probabilities. Having a message we can forge and present a valid tag for that message with probability 2^{-64} for 8 rounds of the permutation.

Everybody is invited.

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