@misc{cryptoeprint:2011:570,
author = {Jintai Ding and Thorsten Kleinjung},
title = {Degree of regularity for HFE-},
howpublished = {Cryptology ePrint Archive, Report 2011/570},
year = {2011},
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.