Barcode scanning apps for trade shows - open to bidding

We are looking for a complete barcode scanning software solution for trade shows. We need to have barcode (QR or 2D mag strip) for each delegate at the show. Delegates can then scan each other’s barcodes and save the information that is connected with that barcode on a database in the cloud. Each person that wants to use this app will have to pay for it so one payment will get you access to one login on the app. The barcode will have an identity number of sorts in order to fetch the data from the web service. So we will print badges with a barcode with the number 123 encoded onto it lets say. After scanning the barcode, the app sends a request to the server with the id 123. The server then responds with users details. i.e. Oliver Boyers, 27, oliver@[login to view URL], south africa,.... etc. (This database will be pre-populated with data that we have already captured. We would like the app to be available to users on both iOS and Android. The dev does not need to be native. We can use cross platfrom development methods to reduce costs. We would like an admin panel to control access and backend items too. This is what we think the feature list should be: Admin panel -  • issues new user accounts • controls number of logins • deactivate accounts User app (Android and iOS) -  • login (limited logins) • user reset password • scan badges (QR and 2D magstripe) • view scanned leads • add additional info (comments, lead "heat", 5 star rating for lead) • *save info locally • *upload scans to cloud (web service) • Download all scans as csv to device/email to self Web service - • Put new scans into DB • Fetch all scans from DB and send to user • Authenticate login