This is a demo app showing you how to implement QR and barcode scanning in Swift. For the full tutorial, please refer to the link below:
http://www.appcoda.com/barcode-reader-swift/
One of the primary benefits of this solution is that the content of the bar-code visible towards the users do not have to be the actual data entered into the form fields. Especially this would include participant identifiers that can be hidden from the participants.