Nice plugin rojohound
As for "security", randomising the name will do nothing. You can just browse to your temp folder and find it yourself by hand in most cases. Someone could even make a tool to extract all your textures out a compiled EXE, the only reason that doesn't exist is Construct isn't popular enough to get that kind of attention. I say this all the time, but if someone wants to rip stuff out of your game they can and will, it's copyright law that protects you from that, not technical hurdles.