@misc{cryptoeprint:2005:180,
author = {XU Chunxiang and ZHOU Junhui and QIN Zhiguang},
title = {A Note on Secure Key Issuing in ID-based Cryptography},
howpublished = {Cryptology ePrint Archive, Report 2005/180},
year = {2005},
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.