What is the difference between Safety and Security in software systems?

Question

Accepted Answer

Safety protects people from the system; security protects the system from people.

* The CIA triad — confidentiality, integrity and availability, the goals security protects. — Michel Bakni, CC BY-SA 4.0, via Wikimedia Commons. *
Safety and Security protect different things in opposite directions:

Aspect
Safety
Security

Goal
Avoiding hazardous situations
Defense against intrusion and unauthorized use

Protects
Humans and environment FROM systems
Systems FROM humans

Threat
Malfunctioning systems
Malicious or criminal intent

Tip: Safety = Systems don't hurt people. Security = People don't hurt systems.

Aspect	Safety	Security
Goal	Avoiding hazardous situations	Defense against intrusion and unauthorized use
Protects	Humans and environment FROM systems	Systems FROM humans
Threat	Malfunctioning systems	Malicious or criminal intent