We are particularly interested in attacks aiming at recovering the internal state, the secret key or at forging a MAC. Other attacks would be appreciated as well. Competitors have the freedom to increase the input rate of Ketje. The attack can be applied to any of the four instances of Ketje.

Who wins the prize will be decided by consensus in the Keccak team. Some hints:

• Innovative ideas are preferred over incremental results or the application of standard techniques.
• For attacks with innovation levels that are comparable, the earlier ones are favored.
• The smaller the rate (expressed in number of lanes) the better.
• Attacks with reduced-round versions are allowed but the closer to the CAESAR submission the better.
• “Nonce-misuse” results are accepted if presenting very innovative aspects.

The Ketje authenticated encryption scheme has already established such a solid reputation in Belgium that a beer was named after it. Unfortunately, it is already sold out since 2011. Instead, the winner will receive a selection of Belgian beers.

The attacks should be submitted to the crypto-competitions -at- googlegroups.com mailing list (with ketje -at- noekeon.org in CC) before January 31st, 2018.