Mina
Mina is a new cryptocurrency with a constant size blockchain
...The Mina blockchain remains ~22kb, enabling users to quickly and directly access the current state from their smartphone and other blockchains. Users today are compelled to hand over their data to centralized entities in order to participate in the modern world. But Mina’s zkApps, smart contracts powered by zero-knowledge, keep users in control of their privacy by validating and sharing proofs of their data, rather than the data itself. Think about getting a loan by simply sharing a proof of your personal ID and credit score, rather than the data itself. No risk of your personal information being hacked or sold. ...