@misc{cryptoeprint:2013:777,
author = {Yuenai Chen and Chunming Tang},
title = {Construction of Multiplicative Monotone Span Program},
howpublished = {Cryptology ePrint Archive, Report 2013/777},
year = {2013},
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.