Wormhole offers fast, end‑to‑end encrypted file sharing with expiring

Wormhole is a web‑based service that enables users to share files with end‑to‑end encryption and a link that automatically expires, aiming to keep shared data private and short‑lived [1]. The platform supports uploads of up to 10 GB and stores encrypted files for 24 hours, after which the link becomes unusable [2].

Key takeaways

• Files are encrypted on the client side before leaving the browser [1]
• Uploads can be as large as 10 GB and are stored for 24 hours only [2]
• The service targets link generation in under two seconds and streams data instantly [2]
• Peer‑to‑peer transfer uses the WebTorrent protocol when both devices are on the same network or when files exceed 5 GB [2]
• Multiple browser storage APIs are employed to optimise performance, including Storage Foundation, Filesystem Access, Cache, IndexedDB, and in‑memory fallback [2]

Speed and security by design

Wormhole’s developers describe two core goals: delivering a link in less than two seconds and ensuring that no server ever sees the file contents. To achieve this, the service encrypts files using the Encrypted Content‑Encoding standard—also used by the now‑defunct Firefox Send—so memory usage stays flat regardless of file size [2]. While the encrypted data streams to the browser’s storage, it is simultaneously uploaded to Wormhole’s servers. If a downloader connects before the upload finishes, the browser can relay the data directly, allowing the recipient to start downloading immediately [2].

When a file exceeds 5 GB, Wormhole switches to a peer‑to‑peer transfer using the WebTorrent protocol, which operates over WebRTC/TLS. All file data remains encrypted end‑to‑end, and the encrypted payload is also encrypted in transit and at rest on the servers [2]. This hybrid approach balances speed for small files with direct device‑to‑device transfer for larger payloads.

Flexible storage strategies in the browser

The service selects among several browser storage mechanisms based on performance and availability. The preferred option is the experimental Storage Foundation API (Chrome only), followed by the Filesystem Access API, Cache API, IndexedDB, and finally in‑memory storage as a fallback when disk space is limited or private‑browsing mode is active [2]. These choices allow Wormhole to keep the upload process responsive across different browsers and environments.

Why it matters

Wormhole’s combination of client‑side encryption, expiring links, and rapid link generation addresses growing concerns over privacy and data retention in file‑sharing services. By limiting link lifespan to 24 hours and avoiding server‑side decryption, the platform reduces the risk of unauthorized access. The use of WebTorrent for large files demonstrates a practical application of peer‑to‑peer technology within a browser context, potentially influencing future web‑based transfer tools. Continued development, including plans to open‑source the cryptographic code and explore longer retention options, will determine how widely the service is adopted for both casual and business use.