A physical key is used to propose an association between a guest device and user information and services. Contact-based or contact-less connectors are used to establish the proposed association between the physical key and the guest device. The proposed association then communicated to the dynamic authentication system over a first communication channel. The dynamic authentication system determines a user confirmation over a second communications channel based on a user device and previously determined associations between users, user devices and the physical key. The guest device is then authenticated for access to information and/or services associated with the user. The information retrieved from and/or transmitted to the user's personal information repository is optionally protected using various transformations. Optional session identifiers supported on the physical key and/or the user device, ensure the protected information is inaccessible when the physical key is removed and/or the predetermined association with the user device is deleted.