To make your DocbookMD account as secure as possible, we recommend that you enable a PIN lock.
You can enable a Personal Identification Number (PIN) lock, by going to the Menu, then Settings, and turn Lock App with PIN to ON.
Then create your four digit PIN.
Whenever you open the app, you should now have to enter your PIN.
If you leave your mobile device sitting around and someone picks it up, they will need to know your PIN, in order to access your messages.
You may also enable a PIN lock on your mobile phone itself. This will effectively allow you to have two PINs (one on your phone, and one in DocbookMD), allowing the highest security possible.