Crypto shares up on bitcoin strength

** Shares of crypto and blockchain-related companies up in premarket trading as bitcoin rises** Bitcoin , world's biggest cryptocurrency, rises 2.3%, while Ether up 2.1%** Crypto exchange Coinbase Global rises 2.4%, U.S.-listed shares of blockchain farm operator Bitfarms Ltd up 3.5%%** Crypto miners Riot Platforms Inc , Hut 8 Mining and Marathon Digital up between 4.5% and 5%