Your secret stays yours.

Secret Handoff is designed so the service can store and deliver a secret without being able to read it.

Encryption happens in your browser

Your device creates a random 256-bit key and encrypts the secret with AES-256-GCM before upload. The key stays in the link fragment—the part after #—which browsers do not send to web servers.

One retrieval wins

The recipient proves they possess the link key, and the database conditionally destroys the encrypted record as it returns it. Concurrent attempts cannot both succeed. Link-preview scanners never consume a secret because retrieval requires an explicit button press.

Passphrases are a true second factor

When enabled, the passphrase and link key are combined locally using PBKDF2 and HKDF. A wrong passphrase cannot retrieve or consume the ciphertext, and the passphrase is never sent to the service.

Limits reduce abuse

Payload, lifetime, per-address, daily, and total-capacity limits keep the public service predictable. Cloudflare Turnstile protects creation without requiring an account.