Why security is important as a part of an application's architecture

Over the past few years, I have seen many cases of organizations or companies reviewing their software security concerns after having already gone into production. This usually happens when their systems face security issues or their businesses lose money due to downtime or compromised data. 

It is widely known that security concerns and processes should be included as a part of the Software Development Life Cycle (SDLC). Since security is an aspect that should be considered as part of every single application, it is imperative to ensure that our applications and code have security constraints that allow us to feel confident about our software at all stages (design, development, testing, and deployment):

Security as a part of the SDLC

Our main goal should be to prevent our application from being...