SOLID

SOLID is a set of five well-known design principles (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion) for object-oriented programming. You can apply these principles when developing secure code and security applications. In practice, this means, for example: security modules with one clear purpose, extending security functionality without modifying core code, using polymorphism/interfaces to enable substitution of security components, avoiding overly broad security interfaces, and "inverting" dependencies so that high-level security modules do not directly depend on low-level implementations.

Following SOLID makes security codebase more understandable, maintainable, and easier to extend. In security development, where adaptability to new threats is crucial, SOLID prevents the code from becoming difficult to maintain or audit, which itself could introduce security vulnerabilities.

Starting Points

• SOLID Principles in Cybersecurity
• Clean Code and SOLID Principles for Secure Coding

Key Points

• You recognize in your security code design which SOLID principles are relevant and demonstrably apply them.
• You evaluate security code design choices against SOLID principles.
• You avoid anti-patterns that conflict with SOLID (such as security God classes, tightly coupled security logic, etc.) or refactor them to prevent security vulnerabilities.
• You communicate the security architecture with a class diagram or schema, showing how SOLID principles have been applied to maintain security best practices.