Hi DavidR,
I too have these password protected files, and sometimes they are there for a good reason. I know Spybot S&D makes some for its settings, and the same goes for Lavasoft's Ad-Aware. If you do an on line scan with another av platform e.g. the Romanian Bitdefender on line-scanner it mentions them. If Bitdefender cannot get to them, malware does not either.
Have a nice virusfree day,
POLONUS