Colorado's sexting scandal has drawn attention to 'ghost apps' that can hide nude pics

The recent Colorado sexting scandal is drawing a lot of attention because of its sheer scale, but also because of the way students have allegedly shared hundreds of sexually explicit photos: through "ghost apps," or apps that are disguised as normal apps but can turn into a secret photo vault.

"Ghost apps, hidden apps, they're everywhere and kids know about them," Mike Harris, Jefferson County District Attorney Investigator, told NBC Nightly News.

So what exactly are these "ghost apps"?

A quick Google search for vault apps gives you a number of different options that have similar functionalities. Some of them look like a normal calculator app, but once you type in a secret code, it takes you to a hidden page where you can store photos, video, and all kinds of personal information.

Investigators are saying at least 100 Canon City High School kids used such apps to share and store hundreds of nude and semi-nude pics with each other, including students as young as 13. Students involved in the case could face possible charges of possessing and distributing child pornography.

The New York Times points out such vault apps have been in the market since as early as 2012, and some of the popular ones, like Private Photo Vault, is ranked the 28th most downloaded photo and video app on the AppStore, while an app called Secret Calculator Folder Free has over 800 reviews.

The bigger problem is that this may just be a tip of the iceberg. The NBC report stressed that other sexting scandals have been reported in Pennsylvania, Ohio, and Tennessee, recently, and that most schools in the US have seen similar cases in one way or another.

"There isn't a school in the US probably at this point that hasn't dealt with the issue of sexting," said Canon City School Superintendent George Welsh.

Here's a screen shot of the Secret Calculator Folder Free app: