Define common concepts (and maybe explain why you should care about them?) #424

Here's an example for privacy, security, and anonymity:

• Security is preventing unauthorized activity; it's like how a lock on your door prevents unauthorized access to your building.

Formed this definition with the help of this post

• Privacy is preventing unauthorized access to data; it's like how the blinds on your windows prevent outsiders from seeing within.

Formed this definition in response to the aforementioned post mentioning how ambiguously and variably people define privacy, so I made a more clear definition of privacy that tries to show how privacy and security can interact and complement each other.

• Anonymity is not being tied to a persistent identifier, like how different disguises hide secret identities.