Suggestion to add security feature to just notes app

Components

Just notes is an application to write daily notes on android,this application is really simple to use by users without so much annoying or interrupted

Proposal

My proposal to the developer of this app is to add security feature,this feature is really needed to secure privacy's notes of users.

Mockups / Examples

Before security feature added to this app
And after security feature implemented,maybe can be look like this
When the security feature has been added ,the users could put their own pattern or password to keep their notes safe

Benefits

This feature has so much advantage,one of them is to keep privacy's notes of users to be safe so any other people couldn't open it without password or pattern and just that's it from me