@misc{cryptoeprint:2010:415,
author = {Stanislav Smyshlyaev},
title = {Perfectly Balanced Boolean Functions and Goli\'c Conjecture},
howpublished = {Cryptology ePrint Archive, Report 2010/415},
year = {2010},
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.