Smart contracts in Spain; the regulation of smart contracts

Smart contracts are a reality that has been applied for decades, although they have gained relevance due to the discovery of the blockchain. Both the smart contracts that are executed according to said technology and those which take place outside of it, respond essentially to the same scheme: they are code sequences which express or implement existing agreements that can produce legal effects whose essential feature is that they are self-executable autonomously. This paper is dedicated to the study of the legal challenges that arise from smart contracts executed outside the blockchain; in particular, to whether or not they are contracts, to their making process, to the incidence that the error has on them, to their proof in the judicial procedure, as well as to some aspects related to payment. In order to get a full understanding of smart contracts, their meaning, their historical origin, their operation, their advantages and their difficulties will be also analyzed.