The shortage of a central authority may make cryptocurrencies safer. "It is hack-evidence mainly because there isn't any a single central level of failure," clarifies David Donovan, executive vp at Publicis Sapient.??? ??? ????? ????? ??? ??????? ????? ???? ??????? ?? ???? ???????? ??? ??? ??????????? ?????????? ?? ??????????????? ??? ?????????"Cry