The Observer World: A Cryptographic Extension of Impagliazzo's Five Worlds (opens in new tab)

Impagliazzo's five worlds classify computational assumptions along a single axis, the existence of cryptographic primitives. All five worlds implicitly assume that every party, including the adversary, observes the full input, that the observer is always $O_{top}$. This assumption is so natural that it is never stated. This work makes it explicit and relaxes it by introducing a second, orthogonal axis, the observational axis, defined by the obse...