@misc{cryptoeprint:2014:198,
author = {Eric M. Mahé and Jean-Marie Chauvet},
title = {Fast GPGPU-Based Elliptic Curve Scalar Multiplication},
howpublished = {Cryptology ePrint Archive, Report 2014/198},
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.