Cryptology ePrint Archive: BibTeX Citation of Report 2011/510

@misc{cryptoeprint:2011:510,
    author = {Seung Geol Choi and Jonathan Katz and Ranjit Kumaresan and Hong-Sheng Zhou},
    title = {On the Security of the Free-XOR Technique},
    howpublished = {Cryptology ePrint Archive, Report 2011/510},
    year = {2011},
    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.