Cryptology ePrint Archive: BibTeX Citation of Report 2012/677

@misc{cryptoeprint:2012:677,
    author = {Jialin Huang and Xuejia Lai},
    title = {What is the Effective Key Length for a Block Cipher: an Attack on Every Block Cipher},
    howpublished = {Cryptology ePrint Archive, Report 2012/677},
    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.