Currently, Coinbase and Bittrex are no longer secure. Bittrex is having very low volume and is showing signs of release from the management team, they seem to have no recent events. It looks like they are about to let go of it and create something new. As for Coinbase, only Americans should use it, in addition, we should not use it. There have been many cases of account lockout for no reason and no one to support to get back the account.