I. Introduction
Blockchain technology bases its operation on the ability of each node in its network to evaluate the correctness of each new block. Each node must therefore be able to evaluate whether the new block is consistent with the state of the blockchain. Each node evaluates in a deterministic fashion and independently from the other nodes if each transaction in the new block is valid. All fair nodes that have to examine the same block will arrive at the same conclusion, since the evaluation is based on the same inputs and follows the same evaluation criteria.