I've honestly fallen back to HTTP/SFTP. I just rent a VPS, temporarily host the file on there, and give whoever it is a link. Edit: If my threat model were to

I've honestly fallen back to HTTP/SFTP. I just rent a VPS, temporarily host the file on there, and give whoever it is a link. Edit: If my threat model were to include protecting the contents of the file from the VPS provider I would probably encrypt it client side with GPG or something similar.