We announce the second prize for the most interesting cryptanalysis of Keccak. The results must be publicly available on an URL that is sent to keccak -at- noekeon -dot- org before June 30, 2009 at 23:59 GMT+2. We reserve the right to extend this deadline in the absence of interesting results.

This time, the prize is a Bialetti coffee machine of fine Italian design, plus a set of some of the best Italian coffee.

Like for the previous prize, who wins will be decided by consensus in the Keccak team, based internally on a system of points. Some hints:

• Innovative ideas get more points than incremental results or applying standard techniques;
• For attacks with innovations that are comparable, the earlier ones get more points;
• Cryptanalysis or attack techniques applicable to a wider range of valid parameters r, c get more points (see the specifications for the definition of valid parameters);
• Larger Keccak-f width gets more points;
• Larger capacity gets more points;
• Attacks on reduced-round versions are allowed but more rounds get more points.

We hope analyzing Keccak is a fun and interesting challenge, and we appreciate any submitted work!