The free AppLock - App Vault & Gallery Lock for Android is a useful utility to secure your personal photos, videos, audio recordings, and other files from unauthorized access. This is a free, easy-to-use, and user-friendly application that allows you to protect your data with a simple and intuitive interface. With this application, you can lock your photos, videos, and other files so that no one can view them, make in-app purchases, or even delete them. You can also set a password to prevent unauthorized access.

If you are concerned about the security of your Android device, this is the best solution for you.