Cryptology ePrint Archive: BibTeX Citation of Report 2012/596

@misc{cryptoeprint:2012:596,
    author = {Elli Androulaki and Ghassan Karame and Marc Roeschlin and Tobias Scherer and Srdjan Capkun},
    title = {Evaluating User Privacy in Bitcoin},
    howpublished = {Cryptology ePrint Archive, Report 2012/596},
    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.