@misc{cryptoeprint:2014:131,
author = {Janaka Alawatugoda and Douglas Stebila and Colin Boyd},
title = {Modelling After-the-fact Leakage for Key Exchange},
howpublished = {Cryptology ePrint Archive, Report 2014/131},
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.