Common Input Ownership Heuristic

The Common Input Ownership Heuristic is one of the core heuristics used by chain analysis companies to determine the owner of specific UTXOs. This heuristic currently assumes that all inputs of a given transaction are owned by the same owner.

This heuristic has never offered certainty, and as Bitcoin continues to evolve, it is becoming less reliable. Technologies such as CoinJoin, CoinSwap, regular multisig, and, in the future, MuSig transactions all contradict this heuristic by accepting inputs from many different parties.