Just saw this tweak and thought I would share it with you all. It’s called ipicar and its only $1.55 in Cydia. What this tweak does is let you hide your Message app if you unlock your device with a specific passcode. So you won’t want to set this passcode and your normal passcode. Another good thing this tweak does is if you get a message from someone while the Messages app is hidden the notification won’t show on the springboard. 

This tweak is good for if you might let someone use your phone for a few minutes to make a phone call. I would like to see the ability to hide your Photos app added to this tweak as well. So checkout ipicar in Cydia now.