An identity management server can be used to provide identity-based authentication and access control mechanism for devices trying to connect to a network or other devices on the network. The identity management server may authenticate a user associated with a device based on the past behavior information of the user received from another device associated with the user. The identity management server may generate a trust score based on multiple attributes associated with the user and the device, and authenticate the user if the trust score is within an acceptable limit. The identity management server may also generate access permissions for the device, which can be used by a network device to grant or deny access to the network.