@misc{cryptoeprint:2004:169,
author = {Alexander W. Dent and Allan Tomlinson},
title = {Regional Blackouts: Protection of Broadcast Content on 3G Networks.},
howpublished = {Cryptology ePrint Archive, Report 2004/169},
year = {2004},
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.