Digital StrongBox is a simple app to securely store personal information, notes, photos, and videos on your iPhone or iPad so that it is safe from prying eyes. It uses AES-256 encryption, which is certainly strong enough for anyone's purposes and protects your data behind a 4 to 8 digit access code. It requires iOS 7 and up and is a universal app compatible with iPad, iPod Touch, and is optimized for the iPhone 5.
The app is quite easy to use and gives you enough prompting when you first run it to get you going. Initially, you have to set up your access code. It is very important that you remember this code because if you lose it, there is nothing that anyone (including the developer) can do to retrieve it or your data. To help you, the app offers to email the code you have selected to you so that you can store it safely elsewhere (your virtual key under the doormat).
Once you are past this, you are presented with the main screen with on-screen popup notes pointing you towards the three major features: Adding a new photo album, taking a picture with your camera, and importing pictures from your camera's photo library. Each of these behaves as you would expect and as they behave in countless other apps. For example, adding pictures from my library brought up the standard interface for picking multiple photographs from my various photo albums. Once you add pictures to the app it reminds you that if you want these to be secure, you should now delete them from your camera's photo library so they only exist inside Digital StrongBox.
Aside from photos, the other main type of data you can store are notes. These take on four different forms: freeform notes, the kind you find in any notepad, identification documents, financial account information, and passwords. The latter three are simply notes that provide some specific fields and the possibility of attaching pictures in certain cases.
For example, under Financial, you can add in a credit card complete with all pertinent information and pictures of the front and back of the card. For Identification, you can do the same with a social security card or your driver's license. For passwords, well, it's not clear to me (aside from the issue of cost) why one would want to use a tool like this for passwords when 1Password and similar are so much more powerful and can integrate directly with Safari in iOS 8 but if you want to just store them and not auto-fill them, it works well enough.
Across the app, the UI is clean if a little unpolished. It's the small things like auto-capitalization not (always) being on when typing a new title for a note or document or the fact that the "Notes" indicator for the place where you actually enter a notebook entry is vertically centered next to the content and that the content itself has a rather thin column to work with making it feel cramped. But these are really quibbles. Aside from one crash I had when I first tried creating a password note (which I was unable to replicate) the app appears stable and does exactly what it advertises.
If you are looking for a way to store critical information and/or photos and videos privately, then this app is certainly worth a look. Digital StrongBox is free for up to 7 notes and 20 photos/videos. It can be unlocked for US$0.99, giving you unlimited notes and photos/videos.