Hi, I'd like to share our app with you:
FaceLock will protect your apps with your face! Your face is the key to unlock them. With FaceLock for apps, you don't need to wait for Android 4.0 to use face unlock on your phone. FaceLock lets you choose individual apps you want to protect.

The free version will lock the protected apps: market, task manager, settings and one app of your choice. The Pro version includes many more features and lets you protect as many apps as you want.



About security: task manager, settings and market are protected so no one can kill or uninstall FaceLock out of the box. Face recognition is reliable and safe with the default settings. For recognition in difficult lighting you can train more images whenever you are not recognized. For increased security you can raise the security level.

FAQ: http://www.facelock.mobi/tips-and-faq