  "Code is law" refers to the idea that, with the advent of digital technology,
code has progressively established itself as the predominant way to regulate
the behavior of Internet users. Yet, while computer code can enforce rules more
efficiently than legal code, it also comes with a series of limitations, mostly
because it is difficult to transpose the ambiguity and flexibility of legal
rules into a formalized language which can be interpreted by a machine. With
the advent of blockchain technology and associated smart contracts, code is
assuming an even stronger role in regulating people's interactions over the
Internet, as many contractual transactions get transposed into smart contract
code. In this paper, we describe the shift from the traditional notion of "code
is law" (i.e. code having the effect of law) to the new conception of "law is
code" (i.e. law being defined as code).
