Temporal proximity to verify physical proximity

A method for rendering content based on authorization, the method comprising:

• requesting a plurality of data items corresponding to a data set, the plurality of data items including a selected data item;
• measuring a plurality of response times associated with a plurality of responses to the plurality of requests for the plurality of data items;
• determining by an authorization based at least in part on an assessment of the one or more response times and whether one or more data items other than the selected data item exist in the data set to be available to the renderer;
• and
• rendering the selected data item only if authorized.

A processor for processing information depending on an authorization, the processor comprising:

• a challenge-response device configured to execute a challenge-response protocol between the processor and an access device, during which protocol a security key is exchanged,
• a timer configured to measure a response time between a challenge sent during said protocol and a response to the challenge, the response time being correlated to a physical proximity between the processor and the access device, wherein measuring said response time comprises:
• requesting one of a plurality of data items stored on a medium from the access device at a first time,
• receiving one of the plurality of data items at the processor at a second time, and
• determining a response time corresponding to a difference between the second time and the first time, and
• a verifier configured to terminate the protocol depending at least in part on an assessment of the response time to the challenge, the assessment including a comparison between the measured response time to the challenge and an expected response time to the challenge.

A processor for processing information depending on an authorization, the processor comprising:

• a challenge-response device configured to execute a key exchange protocol comprising a challenge-response between the processor and an access device,
• a timer configured to measure a response time between a challenge sent during said protocol and a response to the challenge, the response time being correlated to a physical proximity between the processor and the access device, wherein measuring said response time comprises:
• requesting one of a plurality of data items stored on a medium from the access device at a first time,
• receiving one of the plurality of data items at the processor at a second time, and
• determining a response time corresponding to a difference between the second time and the first time, and
• a verifier configured to terminate the protocol depending at least in part on an assessment of the response time to the challenge, the assessment including a comparison between the measured response time to the challenge and an expected response time to the challenge.