Secure, Fast and Easy File Transfer

Winden is the private, secure way to send large files at speed. It represents a new paradigm in data transfer, combining Privacy and Security by Design with ease of use.

Winden is identity-free, meaning that senders and receivers don’t need to know each other’s identity to use it. Winden does not require people to sign up or log in. So it is both very convenient and quick to send a file.

All files are end-to-end encrypted, ensuring that only the sender and receiver can see the content. As files are sent ephemerally from the sender to the receiver, they are never stored on our servers. (So both parties need to be online at the same time.)

Unlike other service providers, we don’t ask you to trust us to keep your data safe – we couldn’t access your data even if we wanted to.

Identity-Free and End-to-End Encryption

Privacy and security by design.
Open source code.

Fast and Easy to Use

Everything is made as simple as possible for you to send files from one device to another as fast as possible.

Large File Size Support and Pictures Uncompressed

Send videos and pictures in their original format.

Device Agnostic and Reliable

Send any file to anyone with a web browser.

Winden is now available as a Beta version for you to try out. Send a file via and please let us know your feedback!

  1. Add files to send.
  2. Generate a short code and give the code (or link) to the intended receiver.
  3. Once the receiver has entered the code and accepted the download, the files are sent. As files are sent from the sender’s device to the receiver, both have to be online at the same time.
  4. Transfer complete: the connection closes.

Winden is based on the Magic Wormhole protocol, which was created by developer Brian Warner as a way to safely and securely transfer files or credentials between computers. (Check out Brian’s presentation at PyCon 2016.) Magic Wormhole utilizes a cryptographic protocol called SPAKE2, which ensures that only the sender and recipient can read the data. The file is not stored on a server; it is sent ephemerally, peer-to-peer or through a transit relay.

Least Authority has worked to expand on and improve on Magic Wormhole’s original idea. In 2017, the NLnet Foundation funded our work on the Haskell port and on improving the Rust port of the original Python code base of Magic Wormhole to make it easier to implement for more development. A grant from the Open Technology Fund’s Usability Lab in 2018 supported our collaboration with OKThanks to investigate Magic Wormhole’s potential use cases in highly censored and surveilled parts of the world specifically.

In 2020, we were awarded funding from the NGI_Trust program to explore the scalability potential and sustainability options for Magic Wormhole. We’ve named this project, MW4ALL — Magic Wormhole for All, and have chosen Winden as its product name. In the first phase of the project we investigated how to develop a sustainable product built on Magic Wormhole and to determine how to scale it technically without compromising its security. We also surveyed people across Europe and learned factors that play a role in people’s choice of what tools to use, or not to use, for sending files.

In the second phase of the project, MW4ALL 2.0, we focused on making the protocol ready for web-usage, designed and developed a web interface and conducted further user research. In creating Winden as a product, we’re also developing a business model to provide a source of sustainability for the magic wormhole protocol, infrastructure and apps.

In other words, we’ve been working on bringing the Magic Wormhole protocol to the masses so that everyone can enjoy safe and simple file transfers.

Interested in collaborating or have feedback to share? Email us at