Cryptology ePrint Archive: BibTeX Citation of Report 2014/485

@misc{cryptoeprint:2014:485,
    author = {Shahram Rasoolzadeh, Zahra Ahmadian, Mahmood Salmasizadeh, and Mohammad Reza Aref},
    title = {An Improved Truncated Differential Cryptanalysis of KLEIN},
    howpublished = {Cryptology ePrint Archive, Report 2014/485},
    year = {2014},
    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.