Encrypt a message
Encrypt a file
Up to 2 GB on desktop. The filename is stored in metadata (not encrypted) — change it below if it's sensitive.
======= <<<<<<< Updated upstreamEncrypt a message
Encrypt a File
To encrypt and send a file, drop the file (Max 200Mb)
Note: Filename is not encrypted! Change it if you must.
Drag and drop the file to be encrypted into this dropzone, or click here to select file.
Encrypt a file
Up to 2 GB on desktop. The filename is taken from the file you upload and stored in metadata (not encrypted).
>>>>>>> bead10a (update code)Drag & drop a file here, or click to select.
Share this URL
Only share with people you trust. The fragment after # is the key — it never leaves your browser.
Scan with a phone camera to open on mobile.
Decrypt
Paste a Relay Secret URL into the address bar to begin — or this tab will open automatically when one is detected.
FAQ
Does your server ever see my data?
No. Everything is encrypted in your browser with AES-GCM-256 before upload. The key is derived from a random value we put in the URL fragment (#…), which browsers never send to servers.
What changed vs the old AWS version?
Crypto upgraded from AES-CBC + PBKDF2 10k iterations to AES-GCM-256 (authenticated) + PBKDF2-SHA256 600k iterations. 16-byte salt, 12-byte random IV per message. The blob format is tagged "RSv1" so we can evolve it later.
How big can a file be?
Up to 2 GB on desktop browsers. WebCrypto needs the whole file in memory, so very large files depend on how much RAM the browser will give us.
Can I trust you?
The whole site and Worker are open source on GitHub — read every line yourself, or fork it and run your own. Inspect the network tab while you use the site: you'll only ever see ciphertext leaving your machine.