The dearth of a central authority may also make cryptocurrencies safer. "It's hack-evidence because there is no a single central stage of failure," points out David Donovan, govt vp at Publicis Sapient.? ?????????????? ???? ?????????? ????????? ??? ??? ?????????????? ??? ?????????? ?????????? ???? ????? ?? ??? ???????? ???? ???.?????? ??? ?? ??????