The security is one of the most important points when running a apache server, we will need to make a safe environment where not to allow that the users manipulate and accede to code or programs.
The way to obtain this is using cryptography, which we search secure communications between users and server so that nobody else can accede to the data. This is obtained with cryptography and key exchange.
The other way to secure the system is that if exists some failure in the system or the code, and if a intruder tries to execute code, this person can be disabled, since powerful limitations exist, like not allowing that he executes commands, reads code of others scripts. He cannot modify nothing because he has a user with very limited resources.