Why is there so much talk about security in targeted programming?

Question

I program in C and now I decided to explore the world of POO through the C#language. I see that many people talk about security and this is precisely my doubt, when programming I see that the development environment itself limits me access to private classes as well as their attributes and their methods. When I define this class as public everything that belongs to it is accessible within other classes.

1° Define as private a class protects the programmer’s code or the user’s application?

2° If I access attributes and methods of an A class in a B class I will be compromising the security of the application?

If someone can also give me some tips related to code organization I will be grateful, because I am used to C so I have always modularized my code separated by 2 headers (functions and libraries) and 1 .c where I call all the functions. Since C# has the advents of classes and security:

3° What would be the best way to organize everything in scripts safely?

Answer 1

Security is a property that has nothing to do with object-oriented programming. Perhaps the term was another.

Defining something as private does not protect anything. The compiler does not let you use normal code that calls that member. Nothing prevents the member from being accessed in unusual ways, such as reflection. It does not even protect an instance from accessing private members from another instance of the same class.

This note on the limb is just an indicator of what you shouldn’t do. This has to do with encapsulation, with concealment of information unnecessary to the code. But do not understand concealment with protection. It’s just that it’s in a wrapper, if you want to open it’s all there to see.

Accessing members of a class does not compromise any security. If this were to occur, you wouldn’t even be able to do anything.

It is possible to use private classes, but they are almost never useful, a private class can only be accessed within another class where it has been declared.

C# may be used like this but it is not a language of script.

It becomes complicated to answer the other questions, I suggest asking more specific questions and more details.

I also suggest looking for a structured way to learn these concepts, maybe a good book.