jmr/CryptoCurrencyLProtonmail shows interest on Blockchain: https://www.reddit.com/r/CryptoCurrency/comments/b1dreg/protonmail_shows_interest_in_providing_blockchain/
https://whatsonchain.com/tx/6fa79049310ef24f4a3958c10e7699d299f3d7092d96bedad440452393bac6dc