Techniques for providing secured, automatic log-in and authentication of a user to a website via a browser executing at the user's personal electronic device (PED) include generating a token based on an identifier of the PED and a user identifier, and storing the token at the user's PED for use in validating and authenticating the user and device credentials against those stored at back-end system and/or in another memory location at the device. Based on the persisted token (and optionally on a user preference), the user may be automatically logged in as the user navigates across restricted and unrestricted portions of the website, and/or to other websites (e.g., without the user's knowledge). At least these features enable automatic log-in and authentication to be performed on an as-needed basis, and/or on a per-device basis, thereby providing significantly more secure access as compared to known techniques.