24 CHAPTER 2 About Industrial Networks Table 2.1 Adding Context to User Authentication to Strengthen Access Control Good User accounts are classified by authority level Assets are classified in conjunction with user authority level Operational controls can be accessed by any device based on user authority Better User accounts are classified by functional role Assets are classified in conjunction with function or operational role Operational controls can be accessed by only those devices that are within a functional group Best User accounts are classified by functional role and authority Assets are classified in conjunction with function and user authority Operational controls can only be accessed by devices within a functional group by a user with appropriate authority Access Control Access control is one of the most difficult yet important aspects of cyber security.