Re: is there any apps for lock msg, gallery,whatsapp n viber
Welcome to Windows Central.
If your looking for an app that would "lock" your Messaging, Photo Hub, WhatsApp, Viber and other apps from other users, then there is no such thing. For that purpose, a four-digit pin code can be set for the lock screen. In case someone else has to borrow your phone, there's Apps Corner and Kid's Corner for that. Windows Phone sand boxing technology prevents third party apps from interfering with or modifying other apps - hence, your apps cannot be locked by another app.
There are lock apps in the store that have been developed to "lock" certain apps in a "folder", but those lock apps are a deliberate deception: Apps will be linked to a certain tile and that tile can only be opened if you enter a code... BUT, those are only shortcuts or links to the real apps. The real apps can still be accessed in the App List (swipe right from Start Screen) and can be pinned to the Start Screen. So the apps were not locked at all.