@misc{cryptoeprint:2010:166,
author = {Ruilin Li and Jianxiong You and Bing Sun and Chao Li},
title = {Fault Analysis Study of the Block Cipher FOX64},
howpublished = {Cryptology ePrint Archive, Report 2010/166},
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.