Cryptology ePrint Archive: BibTeX Citation of Report 2012/339

@misc{cryptoeprint:2012:339,
    author = {Adi Shamir and Eldad Zinger},
    title = {Practical Polynomial Time Known Plaintext Attacks on a Stream Cipher Proposed by John Nash},
    howpublished = {Cryptology ePrint Archive, Report 2012/339},
    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.