0K (zero K) or 0-K may refer to: * 0k, an abbreviation for zero killed (used by bombers during World War II) * 0K, an abbreviation for the temperature zero Kelvin, or Absolute zero * 0K, an abbreviation for Zero knowledge in cryptology * Zero-knowledge proof * Non-interactive zero-knowledge proof * Zero-knowledge password proof * 0K, an abbreviation for zero keel, a type of Suspension keel * Zero-K, an open source real time strategy game * Zero K, a novel by Don DeLillo