US Patent 11651638 Access control system and access control method using the same

Disclosed herein are an access control system and an access control method using the same. The access control method in which a door operating device determines whether to open a door on the basis of an authentication token acquired from a user terminal without intervention of an authentication server includes obtaining the authentication token from the user terminal; determining whether the user have authorization for accessing the door based on a authentication information included in the authentication token; controlling the door to be opened in case of determined that the user have authorization for accessing the door.