Cryptocurrency meets CAP Theorem

Abstract

Guerraoui et al. [PODC, 2019] implement a cryptocurrency (in a permissioned setting) using an asset transfer object. Their main result implies that consensus is not necessary for implementing a cryptocurrency, since computationally speaking, an asset transfer object is equivalent to an atomic read/write register. In this work, we take a step further to understand fundamental limitations of cryptocurrency under the CAP framework. Particularly, we show that no cryptocurrency that tolerates Byzantine adversary works in a partitioned network. We point out future directions that can circumvent the impossibility.