@misc{cryptoeprint:2010:274,
author = {Joseph K. Liu, Joonsang Baek and Jianying Zhou},
title = {Online/Offline Identity-Based Signcryption Revisited},
howpublished = {Cryptology ePrint Archive, Report 2010/274},
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.