@misc{cryptoeprint:2009:365,
author = {Abhishek Parakh and Subhash Kak},
title = {Space Efficient Secret Sharing: A Recursive Approach},
howpublished = {Cryptology ePrint Archive, Report 2009/365},
year = {2009},
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.