XML SafeSave is a simple, compact and efficient data storage code library for Unity.
You can use it to store your game's data easily inside xml files. It even features an option to encrypt your data, in order to protect it against particularly curious end users.
The keys are managed automatically for you, so that you don't have to wildly pass them around your scripts back and forth, and store them in eventually unsafe places.
XML SafeSave is very simple to use, efficient, user friendly and versatile.
You can check out the tutorial video about XML SafeSave on YouTube to find out how it works (and how simple it is).
The API is well documented, featuring helpful VS Intellisense comments, two example scripts, scenes and a tutorial PDF file on how to use it.