  Secure communication that allows only the sender and intended recipient of a
message to view its content has a long history. Quantum objects, such as single
photons are ideal carriers for secure information transmission because,
according to the no-cloning theorem [1], it is impossible to create an
identical and independent copy of an arbitrary quantum state while its
detection leads to the information distortion. BB84 [2,3] is the first quantum
cryptography protocol for a quantum key generation and distribution, based on
single photon sources. This quantum key is used for coding and decoding of
classical information. We propose completely different protocol based on a
stochastic decay of an ensemble of radioactive nuclei randomly emitting a
stream of gamma-photons. We experimentally demonstrate a method how to transmit
classical information containing binary bits (0 or 1) with the help of this
stream. Transmission is organized such that eavesdropping is impossible since
the presence of information in the stream of randomly emitted gamma-photons can
be hidden. Reading of this information needs precise knowledge of the
repetition rate of its sending in advance. It is unrealistic for the
eavesdropper to disclose this rate, and without knowledge of this parameter it
is impossible to make the transmitted information visible.
