@misc{cryptoeprint:2014:287,
author = {Georg T, Becker and Raghavan Kumar},
title = {Active and Passive Side-Channel Attacks on Delay Based PUF Designs},
howpublished = {Cryptology ePrint Archive, Report 2014/287},
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.