@misc{cryptoeprint:2015:101,
author = {Nicky Mouha and Atul Luykx},
title = {Multi-Key Security: The Even-Mansour Construction Revisited},
howpublished = {Cryptology ePrint Archive, Report 2015/101},
year = {2015},
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.