@misc{cryptoeprint:2005:218,
author = {W. Charles Holland and Boaz Tsaban},
title = {The conjugacy problem and related problems in lattice-ordered groups},
howpublished = {Cryptology ePrint Archive, Report 2005/218},
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.