Strongbox now supports the YubiKey 5Ci hardware token and is the first iOS app to support this on KeePass!

This is a key from Yubico that works with iOS devices over the lightning port. The key performs a HMAC-SHA1 Challenge Response which can be used as an additional factor to protect your KeePass database (KeePassXC CR mode).

You can create a YubiKey protected database like so:

1. Tap the ‘ ’ button in the top right
2. Choose ‘New Database (Advanced)’
3. Choose Storage Location (e.g. Local Device)
4. The ‘Set Credentials’ screen will popup.
5. Enter a Password (optional)
6. Under the YubiKey section choose Lightning and which ever slot you programmed for HMACSHA1 Challenge Response.
7. Tap ‘Create’
8. You will be prompted to insert your YubiKey 5Ci now if it's not already inserted.

Fuller instructions here.