Are QR codes secure to use?

Answer 1

I'd say no. They can direct you to harmful urls

Answer 2

anyone can scan them and get their content with a smartphone. They are practical more than secure.

Answer 3

Depends, if the QR code is trusted (inside an app like Mario Run just to make an example) then sure, otherwise no, but if u mean to use it in one of ur programs then yeah u can do that no problem.