Cryptology ePrint Archive: BibTeX Citation of Report 2015/841

@misc{cryptoeprint:2015:841,
    author = {Vanga Odelu and Ashok Kumar Das and Adrijit Goswami},
    title = {An Efficient CP-ABE with Constant Size Secret Keys using ECC for Lightweight Devices},
    howpublished = {Cryptology ePrint Archive, Report 2015/841},
    year = {2015},
    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.