@misc{cryptoeprint:2014:275,
author = {SK Hafizul Islam},
title = {Identity-based encryption and digital signature schemes using extended chaotic maps},
howpublished = {Cryptology ePrint Archive, Report 2014/275},
year = {2014},
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.