@misc{cryptoeprint:2015:252,
author = {Haiyan Wang, Jianghua Zhong, Dongdai Lin},
title = {Linearization of Multi-valued Nonlinear Feedback Shift Registers},
howpublished = {Cryptology ePrint Archive, Report 2015/252},
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.