@misc{cryptoeprint:2010:125,
author = {M. J. Jacobson, Jr., R. Scheidler, AND A. Stein},
title = {Cryptographic Aspects of Real Hyperelliptic Curves},
howpublished = {Cryptology ePrint Archive, Report 2010/125},
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.