Cryptographic encryption scheme based on metastable excited nuclei

The novelty of quantum cryptography is that whenever a spy tries to eavesdrop the communication he causes disturbances in the transmission of the message. Ultimately this unavoidable disturbance is a consequence of Heisenberg's uncertainty principle that limits the joint knowledge of complementary observables. We present in this paper a novel and highly speculative approach. We propose to replace Heisenberg uncertainties by another type of uncertainty, that characterizes the knowledge of the time at which an unstable nucleus decays. Previously developed protocols of quantum cryptography make it possible to refresh a key even in the case that we do not trust the carrier of the key. This scheme might do so as well.