Abstract: A secure-network-communication method capable of encrypting communications from a data-generation source to the entrance of a database regardless of the means of communication, which includes: (1) initialization of an endpoint, whereby the application gateway generates asymmetric authenticators, stores one of the authenticators in a whitelist and stores the other authenticator in the endpoint; (2) authentication at the time of initialization of the endpoint, whereby, if a relay gateway determines that the endpoint is valid, the relay gateway generates asymmetric authenticators including random numbers, and updates and stores the authenticators at the application gateway and at the endpoint, respectively; and (3) arrangement of common keys, whereby the relay gateway generates each part of two different encryption keys, and the application gateway, and transmits each part of the two different encryption keys to the application gateway and the endpoint, and the application gateway and the endpoint respectively g