Cryptology ePrint Archive: BibTeX Citation of Report 2015/212

@misc{cryptoeprint:2015:212,
    author = {Christof Beierle and Philipp Jovanovic and Martin M. Lauridsen and Gregor Leander and Christian Rechberger},
    title = {Analyzing Permutations for AES-like Ciphers: Understanding ShiftRows},
    howpublished = {Cryptology ePrint Archive, Report 2015/212},
    year = {2015},
    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.