@misc{cryptoeprint:2001:072,
author = {T.Moh and Jiun-Ming Chen},
title = {On the Goubin-Courtois Attack on TTM},
howpublished = {Cryptology ePrint Archive, Report 2001/072},
year = {2001},
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.