@misc{cryptoeprint:2011:043,
author = {Jayaprakash Kar},
title = {Proxy Blind Multi-signature Scheme using ECC for handheld devices},
howpublished = {Cryptology ePrint Archive, Report 2011/043},
year = {2011},
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.