Cryptology ePrint Archive: BibTeX Citation of Report 2015/812

@misc{cryptoeprint:2015:812,
    author = {Alex Biryukov and Léo Perrin and Aleksei Udovenko},
    title = {The Secret Structure of the S-Box of Streebog, Kuznechik and Stribob},
    howpublished = {Cryptology ePrint Archive, Report 2015/812},
    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.