FIDO2 / Passkey
"What this device can sign for."
What it proves
Possession of a private key bound to a hardware-backed credential. Phishing-resistant by construction; the browser refuses to sign for a domain that isn't asking.
How it works
Standard WebAuthn / FIDO2 ceremony. AuthenSee derives a commitment from the assertion and feeds it into the proof circuit instead of speaking the assertion directly to the verifier.
When to compose
Always. This is the workhorse factor — fast (≈40ms), supported on every modern device, and the strongest thing we can ask of the OS.