@shahid,
Software security assurance is a process that helps design and implement software that protects the data and resources contained in and controlled by that software. Software is itself a resource and thus must be afforded appropriate security.
Since the number of threats specifically targeting software is increasing, the security of our software that we produce or procure must be assured. "Dependence on information technology makes software assurance a key element of business continuity, national security, and homeland security."