There IS a manual backup and restore system, but this is hidden behind the in-app-purchase (£1.69) so that it can't be tested in advance of buying, which is a bit crazy. Plus you have to remember to do the backups. Plus there are no import or export facilities. So Mobile Vault is all very 'my first secure database', though hopefully it can be developed further (and offer a 7 day trial of premium features, at the very least).
From the Store description:
With Mobile vault, you can safely store any data that you like, such as reminders, memories, text, numbers, etc. Mobile vault is protected with the user's PIN code and stored data is encrypted with the Advanced Encryption Standard (AES) in the encrypted database. This Application run on all devices that run Windows 10 (Desktop, tablet, mobile )
Some screenshots - nothing too earth shattering, but maybe this will prove useful for stashing away secret information in small quantities?
The interface is nicely theme-able, see below left, big and bold, though it's quirky, to say the least. For example, when showing an entry there's no way to edit it, instead you have to long press on the entry's title in the main list!
Some of the themes available. Entries can contain half a dozen text strings, plus a longer Notes field. Everything is local but can be backed up in various ways, as shown above, right. I'm guessing that 'Create backup as file' might mean an export of sorts, but as there's no way to try this without paying then your guess is as good as mine!
This is in the Store here. Maybe worth keeping an eye on for updates?