@misc{cryptoeprint:2008:255,
author = {Xin Liao and Qiao-yan Wen},
title = {Embedding in Two Least Significant Bits with Wet Paper Coding},
howpublished = {Cryptology ePrint Archive, Report 2008/255},
year = {2008},
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.