The Native Core
The rules that move your economy's money never run where anyone can see them.
Most plugins are pure Java, which anyone can open up and read. ProtonAuctions keeps its sensitive parts, the actual money and item logic, in a native core: a compiled library that runs the important steps as encrypted instructions inside its own small machine. There is no tidy block of code to find, read, and rewrite.
It guards itself
Every time it starts, the core checks that nothing has been altered, its own file and the plugin's key files alike. If anything has been touched, it does not quietly carry on with changed rules. It refuses to run. A patched or cracked copy does not get a second chance.
It never turns on your server
Here is the part that matters to you as an owner: all of this points at the plugin, never at you. The core guards the trade logic, and that is its whole job. Whatever happens with your licence, it never locks, deletes, or damages your data. Your economy stays yours.