????? ????????? ??? ???? ??? ?????????; ????????? ???? ??????? ??????? ??? ???????? ??? ?? ??? ????? ?????????? ? ?????????.Cryptocurrencies use many timestamping techniques to "demonstrate" the validity of transactions additional into the blockchain ledger without the need for just a reliable 3rd party.? ??????? ????? ??? ? ???? ?????????? (??? ??