Apple announced Mountain Lion, the next generation of its OS X operating system, will be released next summer. Apple has added a new security feature called Gatekeeper to its iOS operating system. Gatekeeper checks apps before they are installed, but only when they are downloaded over the Internet. Some pundits dismiss Gatekeeper as almost worse than worthless because it only does the validity check when the software is installed. Some are worried that this is the next step in a progression that would wind up with OS X being as closed as iOS.”]
Source: https://www.csoonline.com/article/2130955/apple-s-gatekeeper–a-low-cost-for-partial-security.html