Quiz Entry - updated: 2026.07.14
What is the difference between a Use Case (UC) and a Misuse Case (MUC)?
A Use Case is wanted behavior that should happen (functional); a Misuse Case is unwanted behavior that should NOT happen (security) — performed by an attacker, not a user.
Comparison:
| Aspect | Use Case (UC) | Misuse Case (MUC) |
|---|---|---|
| Behavior | Wanted | UN-wanted |
| System Goal | Should happen | Should NOT happen |
| Requirement Focus | Functional | Security |
| Actor | User (legitimate) | Attacker (malicious) |
Visual Distinction:
- Use Cases are typically shown in white/light ovals
- Misuse Cases are typically shown in black/dark ovals
Key Insight: By explicitly modeling what attackers might do (misuse cases), you can identify security requirements to prevent those attacks.
Tip: UC = white oval (wanted), MUC = black oval (unwanted) — the visual contrast makes threats immediately visible in the diagram.
Go deeper:
Misuse case (Wikipedia) — the inverse-of-a-use-case concept; threatens / mitigates relationships.