@misc{cryptoeprint:2003:136,
author = {Boaz Tsaban and Uzi Vishne},
title = {Efficient linear feedback shift registers with maximal period},
howpublished = {Cryptology ePrint Archive, Report 2003/136},
year = {2003},
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.