@misc{cryptoeprint:2014:100,
author = {Guo-Qiang Liu and Chen-Hui Jin and Chuan-Da Qi},
title = {Improved Slender-set Linear Cryptanalysis},
howpublished = {Cryptology ePrint Archive, Report 2014/100},
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.