ABC: Asynchronous Blockchain without Consensus

We relax the definition of consensus for the purpose of an efficient cryptocurrency and introduce a new blockchain architecture called ABC that offers the typical functionality of a cryptocurrency. By foregoing the assumption of establishing consensus, we are able to design ABC with an array of advantages compared to typical blockchain protocols: ABC is permissionless, deterministic, and resilient to complete asynchrony. ABC features finality and does not rely on wasteful proof-of-work. Without establishing consensus, ABC cannot support certain applications, in particular smart contracts that are open for interaction with unknown agents. However, our system is an advantageous solution for many important use cases, such as cryptocurrencies like Bitcoin.