Cryptology ePrint Archive: BibTeX Citation of Report 2012/218

@misc{cryptoeprint:2012:218,
    author = {T-H. Hubert Chan and Mingfei Li and Elaine Shi and Wenchang Xu},
    title = {Differentially Private Continual Monitoring of Heavy Hitters from Distributed Streams},
    howpublished = {Cryptology ePrint Archive, Report 2012/218},
    year = {2012},
    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.