@misc{cryptoeprint:2007:440,
author = {Sunder Lal and K.K.Goyal},
title = {An Improved Remote User Authentication Scheme using Bilinear Pairings},
howpublished = {Cryptology ePrint Archive, Report 2007/440},
year = {2007},
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.