Allthenticate, an MIT spinout founded in 2019, delivers passwordless authentication using a single smartphone credential for laptops, servers, web apps, and physical doors. It combines Bluetooth proximity login with automatic lock, a device-bound USB-over-Bluetooth FIDO2 roaming passkey, and an OIDC/SAML IdP for SSO. Its patented Rescue Mission uses Shamir Secret Sharing and trusted contacts for decentralized account recovery; scaling, integrations, and visibility remain key challenges.