## Cryptology ePrint Archive: Report 2016/754

Practical Key Recovery Attack on MANTIS-5

Christoph Dobraunig and Maria Eichlseder and Daniel Kales and Florian Mendel

Abstract: MANTIS is a lightweight tweakable block cipher recently published at CRYPTO 2016. In addition to the full 14-round version, MANTIS-7, the designers also propose an aggressive 10-round version, MANTIS-5. The security claim for MANTIS-5 is resistance against "practical attacks", defined as related-tweak attacks with data complexity $2^d$ less than $2^{30}$ chosen plaintexts (or $2^{40}$ known plaintexts), and computational complexity at most $2^{126-d}$.

We present a key-recovery attack against MANTIS-5 with $2^{28}$ chosen plaintexts and a computational complexity of about $2^{38}$ block cipher calls, which violates this claim. Our attack is based on a family of differential characteristics and exploits several properties of the lightweight round function and tweakey schedule. To verify the validity of the attack, we also provide a practical implementation which recovers the full key in about 1 core hour using $2^{30}$ chosen plaintexts.

Category / Keywords: secret-key cryptography / cryptanalysis, MANTIS, PRINCE-like ciphers

Date: received 4 Aug 2016, last revised 30 Aug 2016

Contact author: maria eichlseder at iaik tugraz at

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2016/754

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