Update on Finalist Grøstl

Dear all, as announced in December the Grøstl hash function has been tweaked for the final round. The round3mods, updated specification, implementation and cryptanalysis are available at www.groestl.info. For the final round we have * significantly increased the size of the round constants to make the internal differential attack and its extensions impossible * and use different rotation constants in Q to make P and Q more different which further increases the security margin by one round. Note that the link on the NIST Round3 website still points to the Round2 submission package. Dear all, please find a 2-page summary+appendix entitled "Update on Finalist Grøstl" in the attachment.