@misc{cryptoeprint:2014:831,
author = {Jérémy Jean and Ivica Nikolić and Thomas Peyrin},
title = {Tweaks and Keys for Block Ciphers: the TWEAKEY Framework},
howpublished = {Cryptology ePrint Archive, Report 2014/831},
year = {2014},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.