Cryptology ePrint Archive: BibTeX Citation of Report 2015/206

@misc{cryptoeprint:2015:206,
    author = {Bren Cavallo and Giovanni Di Crescenzo and Delaram Kahrobaei and Vladimir Shpilrain},
    title = {Efficient and Secure Delegation of Group Exponentiation to a Single Server},
    howpublished = {Cryptology ePrint Archive, Report 2015/206},
    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.