Cryptology ePrint Archive: BibTeX Citation of Report 2006/213

@misc{cryptoeprint:2006:213,
    author = {Ueli Maurer and Yvonne Anne Oswald and Krzysztof Pietrzak and Johan Sj{\"o}din},
    title = {Luby-Rackoff Ciphers from Weak Round Functions?},
    howpublished = {Cryptology ePrint Archive, Report 2006/213},
    year = {2006},
    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.