OnionShare Is An Anonymous, Secure, Open Source, And Easy Way To Share Files

There are plenty of centralized file sharing options which typically require a user to hand over identification information and even payment, such as DropBox. If a file sharing service is free it often pops up shady advertisements, and can be clunky to use. More importantly, centralized file sharing services are typically not secure, and the file could be viewed by the company running the service or intercepted by a 3rd party.

OnionShare solves these problems and is incredibly easy to use. Micah Lee, Director of Information Security at The Intercept developed OnionShare. Lee previously worked at the Electronic Frontier Foundation, an organization dedicated to protecting free speech, privacy, and innovation, as well as the Freedom of the Press Foundation which protects, defends, and empowers journalists, in addition to the Distributed Denial of Secrets project which aims to enable the free transmission of data, and the Tor Project.           

Simply download OnionShare, which is conveniently available for MacOS, Windows, Ubuntu, and Fedora. As soon as it is downloaded there is an easy to use interface where you can drag and drop the files you want to send, and then you simply click start sharing. OnionShare then gives you a .onion link to the file.

This sort of link can only be opened with the Tor Browser, and this is an excellent tool to have in general. Tor is short for The Onion Router, and it is named after an onion since its encryption is nested like the layers of an onion. Tor encrypts a user’s internet data multiple times, including the destination IP address, and this data is sent through a relay of nodes around the world. Each node decrypts a layer of the data so it can know which node to send the data to next. The final relay decrypts the actual data and sends it to the destination. In other words, Tor encrypts a user’s data and bounces it between some of the thousands of relays around the world, so a user’s internet traffic data and IP address cannot be discovered.

Once the person you’re sending the file to opens the .onion link they will then be able to simply download the file, and it is actually faster and easier than most other file sharing services. Simultaneously, this is an anonymous way to share files since there is no registration required.

After the person you are sending the file to downloads the file you simply click stop sharing, and the link becomes inactive. There is even an option that as soon as the file is downloaded it will stop sharing, so only one person can download it. This helps ensure that no one else downloads the file in the future, and is far better than many other file sharing services which do not have these sort of kill switch options.

Additionally, the file is not stored on any 3rd party servers. OnionShare creates a server on your own computer and makes it accessible as a Tor onion service, so the file is never stored anywhere but your computer.

Further, since OnionShare uses the Tor browser there is no way to trace the file back to your computer, and the file cannot be intercepted in transit. Likewise, the recipient of the file cannot be traced either.

The one caveat is that user’s of OnionShare must be sure to send the .onion link through an encrypted messaging channel in order to guarantee 100% anonymity. Links sent through Twitter, Facebook, text, or E-mail could be intercepted by 3rd parties. In the near future Cypherpunk Labs will discuss ways to send encrypted messages.

Finally, the OnionShare code is open source, so user’s can verify that OnionShare is doing exactly what it says it is doing. The source code can be found here, and it can even be forked by cypherpunks want to expand on this technology. 

Thus, OnionShare is an anonymous, secure, free, and easy way to send files. Certainly OnionShare is the application to use for sending critical information to another person, but it is even good for sending non-critical files, since it is faster and easier than most other file sharing services.