The basic purpose of Secret inbox is that, if you don’t want to receive messages of particular person you can block his messages. The second main feature of this app is that if you are not the only user of your Smartphone, and you want to hide someone’s message, then use this app, it will allow you to do this. 1 Secret Inbox: 2 Block/Unblock SMS. 3 Make SMS Secret. 4 Reply Secret SMS from app. 5 Timed SMS (will send your message on selected time). 6 Password protected.