I've been studying PHP frameworks and I've been looking for how you would go about properly authorizing a module for classes, methods, and database actions.

For example, lets say I want a framework that includes different modules from different programmers:

1. Some core class may require special access, not all modules should have access to every core class unless authorized to.
2. I do not want one module to be able to call another module's class/method if it is not supposed to be able to.
3. I also don't want a security flaw in one module to be able to affect another module's database tables.

I suppose an easy way to go about this is have a database table for authorization to consult, but I doubt that is the best way to go about this.

I'd appreciate any advice or pointing me in the right direction for some reading.