Cryptology ePrint Archive: BibTeX Citation of Report 2012/085

@misc{cryptoeprint:2012:085,
    author = {Stanislav Bulygin and Michael Walter},
    title = {Study of the invariant coset attack on PRINTcipher: more weak keys with practical key recovery},
    howpublished = {Cryptology ePrint Archive, Report 2012/085},
    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.