Ethereum co-founder Vitalik Buterin explicitly stated in his blog that he supports the adoption of relatively more restrictive "copyleft" software licenses, such as CC-BY-SA and GPL. He pointed out that such agreements require that any derivative works modified or combined with other works must also be open source released under the same agreement, which is more binding than the loose license he previously supported (allowing free use and redistribution). （The Block） https://www. (wublock123.com)/index.php? m=content&c=index&a=show&catid=6&id=45170