WebAuthn `largeBlob` Extension Demo

Register a passkey, write arbitrary data into it, then read it back — all in the browser.

Step 1 — Register

Create a new passkey and request largeBlob support from the authenticator.

No credential stored.

Step 2 — Write

Authenticate with the passkey and write the text below into its largeBlob slot.

Step 3 — Read

Authenticate again and retrieve the data stored in the passkey's largeBlob slot.

Output

— waiting for actions —