@misc{cryptoeprint:2009:153,
author = {Long Hoang Nguyen and A. W. Roscoe},
title = {A new bound for t−wise almost universal hash functions},
howpublished = {Cryptology ePrint Archive, Report 2009/153},
year = {2009},
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.