Thanks for providing this superb application. It has helped me to learn a lot.

The current options are good, but I would request you to consider the following as additional options:

Instead of sending a code to the client to upload, if we provide a login ID to the client, they should be able to send a file. Also when the client logs into the system, if they can see a view of their available downloads, it would be useful. A specific role can be provided wherein, they do not need to fill the recipients. This can be part of configuration.