Locx: App Lock & Photo Vault for Android

With Locx you can lock apps and photos selectively behind a pattern, PIN, or fake lock screen to prevent anyone else from accessing them. It's a well-built and straightforward app without any adds or annoying in-app purchases.

Pros

Solid security features: Rather than locking your entire device, Locx offers selective app locking, which lets you lock or unlock any app on your device with a tap, as well as a Photo Vault into which you can move photos from your gallery to hide and encrypt them. To unlock apps and photos, you can choose between drawing a pattern on the screen or using a four-digit passcode.

Chameleon lock: Besides pattern and PIN code unlocking, this app also introduces an ingenious Chameleon lock screen, which can feature either a make-believe fingerprint scanner or a fake crash message, both of which are in fact unlock methods. Just double tap and then hold your finger on them to unlock.

Light and speedy: The clean material design moves smoothly, whether you're locking/unlocking apps or going through the app's menu to access its different features. On the whole, the app moves and works great while requiring but few resources, having hardly any impact on the battery and weighing less than 2MB.

Cons

Single folder vault: All the images that you add to the vault appear in one folder. Since you cannot add multiple folders, you cannot protect your photos without messing up your collections.

Major security flaw: Protected apps appear in the Recent Apps list. The good news is that the developer is aware of this issue and will fix it in a future release.

Bottom Line

Locx does a good job of helping you protect selected apps and images and, although it does have at least one major security flaw (noted above), it remains a great alternative to password protecting your whole device, especially since it's entirely free. Whether you're concerned that your children may be making unwanted app purchases or just want to protect your apps and photos from strangers, this app can help; it's fast, reliable, and effective.