The Dropbox API for Android or iOS devices [25,26] is a RESTful
API that uses the OAuth protocol to allow an application to access
a folder in the user’s Dropbox area across the Web. To use the API,
a developer must create an online Dropbox application linked to
the developer’s Dropbox account. This generates an “app key” and
“secret key” used to authenticate the application when Dropbox
seeks authorisation from the user to allow the application to access
the user’s area. In development, a Dropbox application can be tested
by up to five users. After the application has been approved by
Dropbox, multiple users can use the service