@misc{cryptoeprint:2012:522,
author = {A. Simone and B. Skoric},
title = {False Positive probabilities in q-ary Tardos codes: comparison of attacks},
howpublished = {Cryptology ePrint Archive, Report 2012/522},
year = {2012},
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.