I gave my Android phone's mac address to an ex-friend, he said: "Give me your mac address and you can connect wirelessly through my home computer". At the time I figured it would save me some data. But now that I think about, I am weary of what he can do with the mac address, and if there are any implications of him being able to steal passwords or control my phone without my knowledge. And if so, what can I do to protect myself, my phone, and personal information? Can he see when I'm online and if I'm offline, can he still access my media files, SMS contacts etc. and use them in a harmful way? Thank you.