@misc{cryptoeprint:2000:004,
author = {J.N. Staddon and D.R. Stinson and R. Wei},
title = {Combinatorial Properties of Frameproof and Traceability Codes },
howpublished = {Cryptology ePrint Archive, Report 2000/004},
year = {2000},
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.