A method, comprising: at a personal user device with one or more processors and memory storing programs for execution by the one or more processors: receiving a request from a shared user device distinct from the personal user device, wherein the personal user device is associated with a user, and the request seeks access to personal information that is associated with the user and stored at a resource server; receiving access authentication information from the user; in response to receiving the access authentication information from the user: sending the access authentication information to an authentication server; receiving an access token from the authentication server, the access token granting access privileges to the personal information associated with the user, the access privileges associated with the access token permitting access to the personal information for a limited period of time; sending the access token to the shared user device, thereby permitting an application executing on the shared user device to use the access token for retrieving at least a portion of the personal information; further comprising extending the limited period of time based on predefined extension criteria, the predefined extension criteria including determining that the personal user device is within a renewal radius of the shared user device; detecting a physical movement of the personal user device, the movement meeting predefined motion criteria, the predefined motion criteria including the personal device moving more than a revocation radius relative to the shared user device; and in response to detecting the physical movement, sending a message to the authentication server to revoke access privileges associated with the access token. at a personal user device with one or more processors and memory storing programs for execution by the one or more processors: receiving a request from a shared user device distinct from the personal user device, wherein the personal user device is associated with a user, and the request seeks access to personal information that is associated with the user and stored at a resource server; receiving access authentication information from the user; in response to receiving the access authentication information from the user: sending the access authentication information to an authentication server; receiving an access token from the authentication server, the access token granting access privileges to the personal information associated with the user, the access privileges associated with the access token permitting access to the personal information for a limited period of time; sending the access token to the shared user device, thereby permitting an application executing on the shared user device to use the receiving a request from a shared user device distinct from the personal user device, wherein the personal user device is associated with a user, and the request seeks access to personal information that is associated with the user and stored at a resource server; receiving access authentication information from the user; in response to receiving the access authentication information from the user: sending the access authentication information to an authentication server; receiving an access token from the authentication server, the access token granting access privileges to the personal information associated with the user, the access privileges associated with the access token permitting access to the personal information for a limited period of time; sending the access token to the shared user device, thereby permitting an application executing on the shared user device to use the sending the access authentication information to an authentication server; receiving an access token from the authentication server, the access token granting access privileges to the personal information associated with the user, the access privileges associated with the access token permitting access to the personal information for a limited period of time; sending the access token to the shared user device, thereby permitting an application executing on the shared user device to use the access token for retrieving at least a portion of the personal information; further comprising extending the limited period of time based on predefined extension criteria, the predefined extension criteria including determining that the personal user device is within a renewal radius of the shared user device; detecting a physical movement of the personal user device, the movement meeting predefined motion criteria, the predefined motion criteria including the personal device moving more than a revocation radius relative to the shared user device; and in response to detecting the physical movement, sending a message to the authentication server to revoke access privileges associated with the access token.