Security
Protecting a system’s data and behavior from abuse, including confidentiality, integrity, and availability risks.
Definition
Security is preventing unauthorized access and resisting abuse.
In system design, security is often about identifying trust boundaries and validating inputs at those boundaries.
Practical security questions
- Who is allowed to do what.
- What data is sensitive.
- Which actions need audit logs.
- How you prevent abuse, like brute force or scraping.
Common mistake
Treating security as a checklist you add at the end.
Security changes architecture because it changes boundaries and data flows.