Security is not something you add at the end of a project; it needs to be part of every stage of the Software Development Life Cycle (SDLC). By thinking about security from the very beginning, you can reduce risks, save time, and build more reliable software.

You will see how each phase of the SDLC—from planning and design to development, testing, deployment, and maintenance—offers unique opportunities to strengthen security. During planning, you set clear security goals and identify potential threats. In design, you create secure architectures and choose trusted components. As you write code, you follow secure coding standards and use tools to catch vulnerabilities early. When testing, you run security scans and review code to find weaknesses before release. During deployment and maintenance, you monitor systems and quickly respond to new threats.

By making security a natural part of your workflow, you protect your software and your users. This approach, known as DevSecOps, helps you build secure, dependable applications from the ground up.

Practical Scenario: Secure SDLC in Action

Imagine you are working on a web application for an online bookstore. You want to make sure the application is secure at every stage of development. Here is how you can integrate security into each step of the Software Development Life Cycle (SDLC):

1. Secure Design:

• Start by identifying sensitive data, such as customer addresses and payment information;
• Plan to use encryption for all personal data stored in the database;
• Design user roles so only authorized staff can access order details.

2. Code Reviews:

• After writing new code, ask a teammate to review your changes;
• Use a checklist to spot common security issues, such as SQL injection risks or missing input validation;
• Discuss suggestions and update your code to fix any problems found.

3. Automated Testing:

• Set up automated security tests in your CI/CD pipeline;
• Run tools that check for known vulnerabilities in dependencies and scan your code for unsafe patterns;
• Make sure tests fail if a security issue is detected, alerting you to fix it before moving forward.

4. Deployment Checks:

• Before going live, run a final automated scan to ensure no secrets, such as passwords or API keys, are exposed in the code;
• Verify that secure configuration settings, like HTTPS and strong password requirements, are enabled;
• Only approve deployment if all security checks pass.

By following these steps, you build security into your workflow, making your application safer for users and easier to maintain.