@misc{cryptoeprint:2014:170,
author = {Shay Gueron},
title = {Parallelized hashing via j-lanes and j-pointers tree modes, with applications to SHA-256},
howpublished = {Cryptology ePrint Archive, Report 2014/170},
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.