@misc{cryptoeprint:2002:032,
author = {Y. Choie and E. Jeong and E. Lee},
title = {Supersingular Hyperelliptic Curve of Genus 2 over Finite Fields},
howpublished = {Cryptology ePrint Archive, Report 2002/032},
year = {2002},
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.