Securing Identity Verification at the Physiological Level

Why We Built Passive Liveness Detection

Active liveness checks were designed to stop basic spoofing attacks, but they introduced a tradeoff: user friction. Every blink prompt, head turn instruction, and smile request adds drop-off to identity verification funnels. Meanwhile, sophisticated attackers learned to defeat challenge-response patterns with increasingly convincing deepfakes and replay techniques.

We recognized that the strongest liveness signal is not something a person does on command. It is something their body does involuntarily. Cardiac blood flow creates rPPG signals in facial tissue that are always present in living humans and absent in every spoofing medium ever created. Building detection around this signal eliminated both the friction problem and the spoofing arms race.

Today, identity platforms, financial institutions, and government agencies deploy Circadify passive liveness to verify millions of identities without ever asking users to perform an action. Presentation attacks are detected at the physiological level, where no synthetic medium can follow.

Our Mission

To secure every identity verification event against presentation attacks using passive physiological detection that requires nothing from the user and leaves nothing for attackers to defeat.