I am writing backend for a mobile app where the login info (user), details of the app and everything used in the mobile app will be on the server side.

That's how I have written the app flow:

• The created users are saved on the server side via registration API

• The newly created users send credentials and after authentication, I generate a dynamic token which is shared with the user for rest of the API calls

• For every other call that a user makes, the token is authenticated and then the response is generated.

• Each login generates a new token so at a time the same user won't be able to use the same account on 2 different mobiles. Since on valid login, a new token will be generated for API usage.

Whole of the communication takes place over SSL so everything is already encrypted. I want to know the security threats that would be saved by OUATH 2 in this scenario.