Cryptology ePrint Archive: BibTeX Citation of Report 2021/1698

@misc{cryptoeprint:2021:1698,
    author       = {Aggelos Kiayias and
		    Cristopher Moore and
		    Saad Quader and
		    Alexander Russell},
    title        = {Efficient Random Beacons with Adaptive Security for Ungrindable Blockchains},
    howpublished = {Cryptology ePrint Archive, Report 2021/1698},
    year         = {2021},
    note         = {\url{https://ia.cr/2021/1698}},
}

You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.