"As soon as the person has downloaded the file, you can just cancel the web server and the file is no longer accessible to anyone," Lee says. So your recipient

"As soon as the person has downloaded the file, you can just cancel the web server and the file is no longer accessible to anyone," Lee says. So your recipient would be the only person to download a file of some specific size at some specific time, from a service that only ever served it once. Traffic analysis is how the Tor network is attacked in practice. Unfortunately, Onionshare is more vulnerable to traffic analysis than even the old GnuPG and Dropbox method.