2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93024A scheme is proposed which stores classical data in 4-state quantum registers. It can achieve the following goal: the classical data can always be read unambiguously, while the quantum registers cannot be copied. Therefore the data provider can always distinguish the original quantum registers from piracy copies. Examples of application are also given.5 pagesQuantum Physicstext