Oracle

Computing. An oracle is a black box that efficiently performs a computation: e.g. a random oracle produces random values, a polynomial oracle evaluates a polynomial $p$ at any requested input point.

An oracle is a black box that solves a specific computational problem in constant time. Oracles are used in the theoretical study of computing and complexity theory.

By interacting with an oracle, one can learn the output of the oracle’s computation but learns nothing about its inner workings.