@misc{cryptoeprint:2008:186,
author = {Mehul A. Shah and Ram Swaminathan and Mary Baker},
title = {Privacy-Preserving Audit and Extraction of Digital Contents},
howpublished = {Cryptology ePrint Archive, Report 2008/186},
year = {2008},
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.