Dropbox’ concept is still deceptively simple. Here’s a folder. Put files in it. Now it syncs. Move to another computing device. It syncs. The folder and files are there now too! The amount of work that goes on behind the scenes of such an application is staggering though. If you’ve ever wondered how Dropbox works, or you’ve always wanted to reverse engineer some code but didn’t know how to get started, read this. We managed to successfully reverse engineer Dropbox, write decryption and injection tools for it that work with current Dropbox clients based on Python 3.6 releases and successfully reverse engineer features and enable them.