Fully named Nude: The Sexiest App Ever, the app uses either a PIN or Touch ID to secure your photos, as well as an integrated camera to take them in the app itself. You can view your naughty photos and video in Nude, too, and the app keeps track of any attempts to get into your photo vault. The iTunes description says you can protect copies of your driver's licence, ID, and credit cards, though it doesn't mention if the built-in AI will detect these in the same way as, say, those naked photos.

Private, on-device analysis is only available with iOS 11, though; users of iOS 10 and under will have their photos categorized by Amazon's cloud-based Rekognition tech, so be wary. Nude is free to download but will run you $1 for a monthly subscription and $10 for an annual one. The app is only on iOS for now, though an Android version is in the works, according to The Verge.