allow acces to files in cpanel only from my android application

I have made an android application which it reads some JSON data from cpanel using JSON library , but next I realise that someone has access to these files and he uses them in his website which it consumes a lot of bandwidth, in fact, anyone can read my files if he founds the direct URL which can be catch easily using some software like Wireshark .

These files are really secrets and I want to block any access not coming from my android application, I used to do that by allowing android user agent only from .htaccess but that's not efficient.