Cryptology ePrint Archive: BibTeX Citation of Report 2014/256

@misc{cryptoeprint:2014:256,
    author = {Iraklis Leontiadis, Kaoutar Elkhiyaoui, Refik Molva},
    title = {Private and Dynamic Time-Series Data Aggregation with Trust Relaxation},
    howpublished = {Cryptology ePrint Archive, Report 2014/256},
    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.