@misc{cryptoeprint:2006:379,
author = {Matthew J. Campagna},
title = {Security Bounds for the NIST Codebook-based Deterministic Random Bit Generator},
howpublished = {Cryptology ePrint Archive, Report 2006/379},
year = {2006},
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.