??? ??? ?? ??????? ?? ????????, ???? ????????? ???? ????-?????????? ?????? ??? ?? ???????? ???? ???????? ??? ????? ?? ???????? ??????????????? ???? ??? ???????? ??? ??? ?? ?????????.Cryptocurrencies use several timestamping schemes to "show" the validity of transactions extra for the blockchain ledger without the need for your reliable 3rd party.?