Gallery Lock, the new smart App Lock, it is designed to prevent apps from accessing the content on your device without your authorization. Free. When you use this application, it acts as a security guard for your smartphone. You have to set it up first, choose the type of lock that you want to use (wall or pattern / random), select a password and then you are all set to allow any apps that are signed into your Google Play app to install themselves on your phone.
As part of Google's new Apps policy, introduced in January, the company does not allow certain apps to be installed on your phone unless you are also using a form of lock. There are still a few exceptions, like Google Reader and Chrome. However, all other applications must use the standard method of unlocking with a user code. Once you have set this up, any app can easily gain access to your private data - text messages, call logs, email, photos etc. - and no one else will have the access to it.
For this new functionality, Google has designed an entirely new unlock process that is unlike anything you have used before. The new Gallery Lock is a completely separate application from the regular version. To gain access to the new functionality, you must first download the Ninex application, which is pre-installed on most phones running the Android OS. Once downloaded, it will register your unique user ID and create a secure link with the appropriate settings. Then you simply need to enter your own user ID and password to allow any other apps to access the information that you have locked away.