@misc{cryptoeprint:2014:601,
author = {Ivan Damgård and Jesper Buus Nielsen},
title = {Adaptive versus Static Security in the UC Model},
howpublished = {Cryptology ePrint Archive, Report 2014/601},
year = {2014},
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.