The software development life cycle (SDLC) is a process that consists of several phases that guide the development of software applications or systems. Security should be involved in every phase of the SDLC, but especially in the planning phase, which is the first phase where the scope, objectives, requirements, and resources of the project are defined. By involving security in the planning phase, potential risks and threats can be identified and mitigated early in the process, which can save time, money, and effort later on. Design, maintenance, implementation, analysis, and testing are other phases of the SDLC, but they are not the first phase where security should be involved. Reference: https://www.bmc.com/blogs/software-development-life-cycle-phases/