@misc{cryptoeprint:2013:765,
author = {Kaoru Kurosawa and Le Trieu Phong},
title = {Kurosawa-Desmedt Key Encapsulation Mechanism, Revisited and More},
howpublished = {Cryptology ePrint Archive, Report 2013/765},
year = {2013},
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.