In my personal rating of annoying things, insincerity ranks second, right after the sudden security pop-ups. Apple's Gatekeeper has accomplished a prodigious feat of tying the two things together in one tight knot of frustration and endless pop-ups. Read here how you can avoid this.
In OS X 10.7.5 commonly known as OS X Lion, Apple introduced a great feature that was thought to make your Mac even more secure than it is now. The new guardian of our digital security was given a fitting name Gatekeeper and was appointed to check the ID of each and every app we may want to install on our Mac.
The mechanism behind this check is pretty straightforward. First, Gatekeeper checks the source, from which you have obtained the app. If it has been downloaded from the Mac App Store, Gatekeeper nods slightly and you can proceed with the installation without any other difficulties. However, if you've downloaded the app from a non-Apple Web source, Gatekeeper checks whether it has a Developer ID. The Developer ID is a unique electronic signature an app developer can get from Apple after a lengthy and cumbersome enrollment process. Any company or individual with a Developer ID is regarded as trusted by Cupertino and Tim Cook personally. Finally, if the app is not signed with a Developer ID or has not been downloaded from the Mac App Store, it is classified as suspicious and you will be warned about this if you try to install it. All in all, you can choose between the three Gatekeeper options allowing you to set the protection level: install the Mac App Store apps only, install the apps with Developer Ids and install any apps no matter where they have been obtained from.
This policy has its pros and cons. For one thing, Gatekeeper doesn't perform any malware checks whatsoever. The only thing Gatekeeper does is checking where you got an app from. The malware detection is carried out by other system mechanisms making use of what is commonly known as 'deny list', i.e. the list of 'unique attributes of the identified malware', as Apple puts it. In other words, if malware is unidentified and its unique attributes are not known, there is a chance it infiltrates your Mac. And that's where Gatekeeper comes into play, as it tells you, 'Hi buddy! Ya know, I never seen that thing before an' I reckon it ain't a very good idea to install it.' The much-hyped Flashback Trojan that infected more than a half of all US Macs would have been effectively sifted out by Gatekeeper; the Java applet it installed in your system to download the malicious code would be marked as coming from an unknown source.
3. If prompted, enter the administrator username and password. Install the program. Now the program can be installed later by any user on your machine even if you uninstall the app. However, if you get it from another source, you will have to repeat the whole procedure.
Have fun with Gatekeeper and take care of your Mac security!