UIID is Web4's identity layer and forms the foundation on which the rest of the ecosystem is built. It gives users a single, self-owned digital identity that lives on their own device rather than on a company's servers.
Instead of traditional passwords, UIID uses device-based, biometric-secured credentials. It also separates a private "Core ID," used for high-trust actions, from an unlimited number of anonymous aliases used for everyday activity — so different services cannot cross-reference a person's behavior across the internet.
Beyond individual users, UIID can also issue verifiable identity credentials to AI agents and automated systems, helping keep automated activity transparent and accountable.