@misc{cryptoeprint:2010:173,
author = {Jean-Luc Beuchat and Eiji Okamoto and Teppei Yamazaki},
title = {Compact Implementations of BLAKE-32 and BLAKE-64 on FPGA},
howpublished = {Cryptology ePrint Archive, Report 2010/173},
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.