Security of data connections

The invention relates to a user safety of data connection. The basic philosophy of this invention transmit the authentication of telephone system is connected subcircuit of between two special data network arbitrating in a network connecting. When a connection; the telephone system connected with the user state of private network a authenticate retransmits to the private network. In turn to provide the true repeater's state, comprising a state information to be marked. End of the encryption to a user state; and common key method to encrypt message. Therefore, session key in the second private network production connected with flowing. The key for key to method and mark encrypting and is transmitted to the first private network in. During connected, provided with symmetrical encryption for session key.