Keybase has a pretty great solution for this. They allow you to upload files sent to anyone based on a popular public account name, so freehunter@hackernews for

Keybase has a pretty great solution for this. They allow you to upload files sent to anyone based on a popular public account name, so freehunter@hackernews for example. Then once that user makes a keybase account, they can access any files attached to accounts they link to their keybase. https://keybase.io/docs/kbfs https://keybase.io/docs/kbfs has more info