@misc{cryptoeprint:2013:479,
author = {B. Skoric},
title = {Security analysis of Quantum-Readout PUFs in the case of challenge-estimation attacks},
howpublished = {Cryptology ePrint Archive, Report 2013/479},
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.