@misc{cryptoeprint:2012:455,
author = {Mike Rosulek},
title = {Must you know the code of f to securely compute f?},
howpublished = {Cryptology ePrint Archive, Report 2012/455},
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.