@misc{cryptoeprint:2005:333,
author = {Ivan Damg{\aa}rd and Kasper Dupont},
title = {Universally Composable Disk Encryption Schemes},
howpublished = {Cryptology ePrint Archive, Report 2005/333},
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.