(a) Except for a party to a private conversation, a person who receives or assists in receiving, or who transmits or assists in transmitting, a private communication may not divulge or publish the existence, contents, substance, purport, effect, or meaning of the communication, except through authorized channels of transmission or reception
- (1) to the addressee or the agent or attorney of the addressee;
- (2) to a person employed or authorized to forward a communication to its destination;
- (3) to proper accounting or distributing officers of the various communicating centers over which the communication may be passed;
- (4) to the master of a ship under whom the person is serving;
- (5) to another on demand of lawful authority; or
- (6) in response to a subpoena issued or order entered by a court of competent jurisdiction.