GnuPG itself is a commandline tool without any graphical stuff. It is the real crypto engine which can be used directly from a command prompt, from shell scripts or by other programs. Therefore it can be considered as a backend for other applications.
Public Keys is a concept where two keys are involved. One key is a Public Key that can be spread through all sorts of media and may be obtained by anyone. The other key is the Private Key. This key is secret and is only available to the owner.
Web Storage takes the principles of older storage mechanisms such as cookies, and makes them more powerful and flexible. With this you can store information in the browser for users to continue working when offline.
Why use Web Storage instead of Web SQL? Web storage is supported on 91.9% of browsers where Web SQL is only supported on 46.39% Though Web SQL allows much more functionality, due to the lack of support on browsers I can not use it. To see the breakdown of which browsers are supported: Web Storage stats: Read More