Geodesic
An attack on $\mathrm{6}$ rounds of Khazad
Matematičeskie voprosy kriptografii, Tome 7 (2016) no. 2, pp. 35-46 
D. A. Burov; B. A. Pogorelov. An attack on $\mathrm{6}$ rounds of Khazad. Matematičeskie voprosy kriptografii, Tome 7 (2016) no. 2, pp. 35-46. http://geodesic.mathdoc.fr/item/MVK_2016_7_2_a2/
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Voir la notice de l'article provenant de la source Math-Net.Ru

We suggest new attacks on the $64$-bit block cipher Khazad. These attacks use some structural properties of its round function. As a result we find $14$ new classes of weak keys for $5$ and $6$ rounds of Khazad. Particularly we show that Khazad has $7$ classes of weak keys for $5$ and $6$ rounds such that the cardinality of each class is $2^{64}$. The time complexity of weak keys recovering is $2^{35}$ $\mathrm{S}$-box lookups for $5$ rounds and $2^{43}$ $\mathrm{S}$-box lookups for $6$ rounds. The corresponding data complexity is $2^{32}$ chosen plaintexts.

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