Non-Functional Requirements (Usability, security)

Ideally the use of software is determined by the performance of both its functionality, such as its usefulness, flexibility, functionality, synergy, security. However, there has been a third-party emphasis on software performance, even if the functionality is not helpful or used without he necessary non-functional features. we discuss the state of the art in the design of non-functional requirements (hereafter, NFRs), while providing hope for some future directions.