Ethereum co-founder Vitalik Buterin stated in his blog that he supports the adoption of more restrictive "copyleft" software license agreements, such as CC-BY-SA and GPL. He pointed out that these types of agreements require any derivative works that are modified or combined with other works to also be released as open source under the same agreement, which has stronger constraints than the permissive licenses he previously supported (which allow free use and redistribution). [The Block]