If you get all your software from Apple’s Mac App Store you probably don’t have to worry about the software package being legitimate. However, not too many Intermediate or Power Users get all their software from the App Store. Many of my Apps are downloaded installs. If you install downloaded software from Developers, it is very important to confirm the legitimacy of the software package. This article describes ways to do that, it is pretty thorough. In the long run, this is all about the security of your Mac.