@misc{cryptoeprint:2021:1036,
author = {Pyrros Chaidos and
Vladislav Gelfer},
title = {Lelantus-CLA},
howpublished = {Cryptology ePrint Archive, Report 2021/1036},
year = {2021},
note = {\url{https://ia.cr/2021/1036}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.