Cryptology ePrint Archive: BibTeX Citation of Report 2012/489

@misc{cryptoeprint:2012:489,
    author = {Zahra Ahmadian, Mahmoud Salmasizadeh, Mohammad Reza Aref},
    title = {Recursive Linear and Differential Cryptanalysis of Ultralightweight Authentication Protocols},
    howpublished = {Cryptology ePrint Archive, Report 2012/489},
    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.