

The core principle is to move away from proprietary software in the automotive sector, which is currently mainly developed by US companies.
I am somewhat suspicious that managers think this means that somebody will develop the software for free.
Sound ridiculous but exactly this is what the industry is expecting from the real-time Linux project.
Depends on how important it is to keep confidentiality.
Best way to secure already written unencrypted data is probably putting the device into a microwave, and then burning it.
For new data on Linux, LUKS encryption should probably be fine.