Proximity Authentication is a technology that logs a person in or out of applications, devices, or other resources using distance as a key measurement and to enforce policies. It requires the user to have a secondary device (e.g. smartphone, wearable) near to the primary device or resource to successfully authenticate.
Proximity authentication is a step along the journey to making security invisible to the user just as continuous authentication does, though the latter’s key policies are risk-based and not proximity-based. Proximity authentication is by definition passwordless. Passive, it uses the architectures, features, and communication protocols of the primary and secondary devices to carry out the authentication.
Proximity authentication can be part of a multi-factor authentication (MFA) solution by using distance for perfunctory access but adding an active component such as a prompt for a user biometric for more privileged access. See Step-Up Authentication.
“At work we have a mobile-initiated authentication system, or phone-as-a-token. Our smartphones give us access into the building, elevators, entryways, desktops, and all resources via SSO. One additional security feature of our system uses proximity authentication to ensure that when are 30 feet away from company resources, it logs us out of them.”