@misc{cryptoeprint:2015:773,
author = {Shoni Gilboa and Shay Gueron },
title = {Distinguishing a truncated random permutation from a random function},
howpublished = {Cryptology ePrint Archive, Report 2015/773},
year = {2015},
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.