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# System prepended metadata

title: SSAS Task 1

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# SSAS Task 1

**Components:**
- three intersections
- **traffic lights** at each intersection, connected to internet and traffic management center
- **traffic management center** shows current status of traffic lights
- **emergency vehicle** can request green wave from traffic management center
- **autonomous vehicles** receive status of traffic lights, can't request traffic light change
- **Mayor vehicle** can request traffic light status, changes traffic light if red light would make it stop


Open questions:
- Traffic light status can be queried by anyone?

## Use case and misuse case diagramm
![](https://i.imgur.com/jywo7sQ.png)




Misuse cases:
- Person that dislikes the mayor and sets all traffic light to red via an emergency vehicle request whenever the mayors car requests a green wave
- Attack on mayor by setting another light to green when a green wave was requested by the vehicle to provoke an accident
- Car race participant wants all lights on red to have an empty intersection
- Terrorist may use violence to acces the traffic control center and sets all lights to green to provoke accidents
- Disgruntled employee uses access to turn off everything to cause chaos
- Use emergency/mayor request to get green light/wave

## (Security) requirements
- "All traffic lights at an intersection shall be connected to the Internet and allow a traffic management centre to control the traffic lights."
- Users need to be authenticated to interact with the system, to allow access only to privileged users
- Unauthorized users can not change traffic lights
- Only emergency vehicles and autonomous vehicles can request green lights
- Green light requests from autonomous cars that are not the mayor's car shall be denied
- Emergency requests have to be prioritized over mayor requests
- Conflicting requests must be resolved in a manner that doesn't endanger traffic participants, for example when two emergency vehicles arrive at an intersection
- All internet traffic must be e2e encrypted, to prevent eavesdroppig & MITM attacks
- Sensitive data must be stored securely and encrypted, to e.g. mitigate risks of data breaches
- Non-Repudiation: Green light/wave requests need to be undeniably traced back to the indivuals that issued them
- If the system fails, it must fail gracefully, (e.g. starting a simple time based traffic light behavior upon failure). The system must never fail in a way that can be dangerous to traffic participants.
- Green light/wave requests must not endanger other traffic participants, including pedestrians (e.g. never allow perpendicular lights to both be green, to prevent crashes)
- All input must be validated, to prevent code injections, buffer overflows etc.
- All requests must be logged, e.g. to notice malicious requests
