The Security, Functionality and Usability Triangle

[Resheph]

The level of security in any system can be defined by the strength of three components; Security, Functionality and Usability. All three components affect each other in that making a system very secure will affect usability and likely also functionality. Accepting less security will likely increase the usability and functionality. All the components affect each other as when the level of one component changes, the others may also change as a result of that change.