@misc{cryptoeprint:2003:246,
author = {Xin L¨¹ and Deng-Guo Feng},
title = {Quantum Digital Signature Based on Quantum One-way Functions},
howpublished = {Cryptology ePrint Archive, Report 2003/246},
year = {2003},
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.