Quantum key distribution protocols and the questions of their protection were studied. There were estimated mutual influences between legitimate users and for any types of cracker attack. For example, BB84 protocol is shown to be unconditional security protocols using photon polarization between outlying channels. Secret keys share between spatially separated (removed or remote) legitimate users. A simple method of generating a dichotomy signal has also been accomplished. In fact, this method can open the way of probabilistic quantum states. We argue that quantum cryptographic systems can be partially simulate on a classical computer with finite degrees of freedom. Quantum entanglement is a basic tool of communication and processing of the information.