Magic Wormhole. It allows two users to send each other a file, and they find each other via a short, English language passphrase (think “horse battery staple”).

It’s a command line python utility so might not be the best solution for completely non-technical people, but I love it.

https://github.com/warner/magic-wormhole https://techcrunch.com/2017/06/27/magic-wormhole-is-a-clever...