When engaged in EDI (Electronic Data Interchange) of PHR (Personal Health Records) between two covered entities or between a covered entity and a contracted entity that has entered into agreement…

When engaged in EDI (Electronic Data Interchange) of PHR (Personal Health Records) between two covered entities or between a covered entity and a contracted entity that has entered into agreement with a covered entity, the covered entities must corroborate that the information exchanged comes from the entity who claims to be sending it. Which of the following is not a way of authenticating the sender?