  It has been proposed in the literature that the volume of Einstein-Rosen
bridge is equal to complexity of state preparation ("Complexity=Volume"
conjecture). Taking this statement outside the horizon, one might be tempted to
propose "Complexity=Time" correspondence. In this Essay we argue that in a
blockchain protocol, which is the foundation of all modern cryptocurrencies,
time is emergent and it is defined according to a version of "Complexity=Time".
