@misc{cryptoeprint:2004:045,
author = {Yehuda Lindell},
title = {Lower Bounds and Impossibility Results for Concurrent Self Composition},
howpublished = {Cryptology ePrint Archive, Report 2004/045},
year = {2004},
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.