@misc{cryptoeprint:2003:263,
author = {Manik Lal Das and Ashutosh Saxena and V P Gulati},
title = {Security Analysis of Lal and Awasthi's Proxy Signature Schemes},
howpublished = {Cryptology ePrint Archive, Report 2003/263},
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.