International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News item: 19 March 2015

Patrick Derbez, Léo Perrin
ePrint Report ePrint Report
NXP Semiconductors and its academic partners challenged the

cryptographic community with finding practical attacks on the block

cipher they designed, PRINCE. Instead of trying to attack as many

rounds as possible using attacks which are usually impractical

despite being faster than brute-force, the challenge invites

cryptographers to find practical attacks and encourages them to

actually implement them.

In this paper, we present new attacks on round-reduced PRINCE including the ones which won the challenge in the

6 and 8-round categories --- the highest for which winners were

identified. Our first attacks rely on a meet-in-the-middle approach and break up to 10 rounds of the cipher.

We also describe heuristic methods we used to find practical SAT-based and differential attacks.

Finally, we also present an analysis of the cycle structure of the

internal rounds of PRINCE leading both to a low complexity

distinguisher for 4-round PRINCE-core and an alternative

representation of the cipher valid in particular contexts and which

highlights, in this cases, a poor diffusion.

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