@misc{cryptoeprint:2015:353,
author = {Paz Morillo and Carla R\`afols and Jorge L. Villar},
title = {Matrix Computational Assumptions in Multilinear Groups},
howpublished = {Cryptology ePrint Archive, Report 2015/353},
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.