??? ????????????? ????? ??? ??? ??????? ????? ????????. ???????? ?? ?? ??????????????? ??? ?? ????????? ???? ???????? ?? ??? ????, ?? ????????? ?????? ?? ?????????? ??????? ??????? ??? ????? ????? ??? ???? , ? ?? ???????? ????????? ?? ??? ??????? ?? ?????????? ??? ??? ???????? ???????? ???.Cryptocurrencies use many timestamping schemes to "demonstr