@misc{cryptoeprint:2015:785,
author = {R\'emi G\'eraud and Diana Maimut and David Naccache},
title = {Double-Speed Barrett Moduli},
howpublished = {Cryptology ePrint Archive, Report 2015/785},
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.