In the same way I can plug my phone into the computer's usb port to charge the power I can also transfer files, or I can plug it in a wall socket but if it has a chip or something it can be uploading virus to my phone, right?
What can a person do to charge a phone's battery in an unknown computer / wall socket without risking downloading a virus or having information from the phone being read without us being aware?
I've heard of stop stopsync, does it work?
also is there any other things we can do or other devices like that?
The USB plug on the charger only has the USB power pins because the data pins are useless to it. The cable itself has them because you can use it for file transfer too, but the charger doesn't because there is no commercially available technology that allows USB data transfer through conventional power plugs.
In short, there is no physical connection between the USB cable's data pins and the wall plug.