DevSecOps represents a natural and necessary evolution in the way development organizations approach security. In the past, security was 'tacked on' to software at the end of the development cycle, almost as an afterthought. A separate security team applied these security measures and then a separate quality assurance (QA) team tested these measures.
This ability to handle security issues was manageable when software updates were released just once or twice a year. But as software developers adopted Agile and DevOps practices, aiming to reduce software development cycles to weeks or even days, the traditional 'tacked-on' approach to security created an unacceptable bottleneck.
DevSecOps integrates application and infrastructure security seamlessly into Agile and DevOps processes and tools. It addresses security issues as they emerge, when they're easier, faster, and less expensive to fix, and before deployment into production.
Additionally, DevSecOps makes application and infrastructure security a shared responsibility of development, security and IT operations teams, rather than the sole responsibility of a security silo. It enables “software, safer, sooner”—the DevSecOps motto–by automating the delivery of secure software without slowing the software development cycle.