ARTS Digital Receipt Transfer

I need a windows service that monitors a directory for created xml documents of digital receipts and then sends them off to a webservice for upload to a database. I will need a webservice to receive the receipts and store them in the database. You will be responsible for creating the sql database that stores the receipts. Must be able to identify customers and associate uploaded receipts to their account in the database. Must be able to identify specific retailer location and reliably query information for their statistics. Windows service should have reliable system for failsafes of not creating duplicates, being failsafe, and threading performance. Web service needs to be able to handle receipt transfer to database in less than a second. Payload should be encrypted via a public/private key encryption standard.