@misc{cryptoeprint:2014:041,
author = {Adi Ben-Zvi and Arkadius Kalka and Boaz Tsaban},
title = {Cryptanalysis via algebraic spans},
howpublished = {Cryptology ePrint Archive, Report 2014/041},
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.