Cryptology ePrint Archive: BibTeX Citation of Report 2010/491

@misc{cryptoeprint:2010:491,
    author = {Yan Zhu and Zexing Hu and Huaixi Wang and Hongxin Hu and Gail-Joon Ahn},
    title = {A Collaborative Framework for Privacy Protection in Online Social Networks},
    howpublished = {Cryptology ePrint Archive, Report 2010/491},
    year = {2010},
    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.