Cryptology ePrint Archive: BibTeX Citation of Report 2015/612

@misc{cryptoeprint:2015:612,
    author = {Gangqiang Yang and Bo Zhu and Valentin Suder and Mark D. Aagaard and Guang Gong},
    title = {The Simeck Family of Lightweight Block Ciphers},
    howpublished = {Cryptology ePrint Archive, Report 2015/612},
    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.