We've got a lot of ways to password-, face-, or gesture-lock our phones, but most of them suffer from the same problem: if your phone is found, it looks like there's something there to discover due to it having a nice little welcome screen asking you to unlock it.
Void Lock is different. It provides security through obscurity by not telling the user that the phone is even working. Kids, friends, loved ones, or serial killers are presented with nothing upon attempting to wake the phone from sleep. Too many attempts and the phone can take a picture and email it to you.
With Void Lock, you can create your own gestures or define keys used to unlock and bring the screen to life. You can also define gestures to launch any applications you choose. A note of caution however: the simpler they are, the more likely someone could accidentally unlock your phone.
Void Lock is free for an ad-supported version, which will display one ad every two hours upon unlocking, or $4.00 for the paid version.