what would be the best way for maastodon to export backups safely to users
an s3-like api is available but the links expire in time and can't easily get generated or cancelled on demand
it could be good enough if there also is good encryption, but
- i'd rather not have to pull keys and handle gpg and tell people to use gpg
- i could generate a random backup encryption key and share it additionally to the signed link, so you need both, and maybe email one. but what encryption and what tools?