OnionShare lets you securely and anonymously share files of any size. It works
by starting a web server, making it accessible as a Tor hidden service, and
generating an unguessable URL to access and download files. It doesn't require
setting up a server on the internet somewhere or using a third party
file sharing service. You host files on your own computer and use a Tor
hidden service to make it temporarily accessible over the internet. The other
user just needs to use Tor Browser to download a file from you.