Cryptology ePrint Archive: BibTeX Citation of Report 2013/620

@misc{cryptoeprint:2013:620,
    author = {Marcin Nagy, Emiliano De Cristofaro, Alexandra Dmitrienko, N. Asokan, Ahmad-Reza Sadeghi},
    title = {Do I know you? -- Efficient and Privacy-Preserving Common Friend-Finder Protocols and Applications},
    howpublished = {Cryptology ePrint Archive, Report 2013/620},
    year = {2013},
    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.