Cryptology ePrint Archive: BibTeX Citation of Report 2009/180

@misc{cryptoeprint:2009:180,
    author = {Haakon Ringberg and Benny Applebaum and Michael J. Freedman and Matthew Caesar and Jennifer Rexford},
    title = {Collaborative, Privacy-Preserving Data Aggregation at Scale},
    howpublished = {Cryptology ePrint Archive, Report 2009/180},
    year = {2009},
    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.