Secure Communication Timing Verification for Card Readers

The patent applies preliminary action by pre-establishing a trusted timing relationship between the card reader and card. The card reader stores the card's identifier and calculates an expected response time window based on predetermined parameters. When a response is received, the reader verifies whether the response time falls within the calculated window before processing, preventing hijacked responses from being accepted while maintaining efficient communication.

The patent implements feedback through a verification mechanism where the card reader checks the timing characteristics of received responses against pre-stored card identifiers and calculated expected time windows. This feedback loop ensures that only responses with valid timing characteristics are processed, automatically rejecting hijacked or falsified responses while maintaining high communication efficiency for legitimate interactions.

The patent applies preliminary action by pre-calculating and storing the expected response time window for each card based on its identifier and predetermined timing parameters. This preparation is done before actual communication occurs, enabling the card reader to quickly verify incoming responses against pre-established criteria without adding significant processing time, thus maintaining high processing speed while ensuring security.

The patent changes the parameter verification approach by shifting from verifying data content integrity to verifying timing characteristics. The card reader compares the actual response time against the expected time window derived from predetermined parameters and the card's identifier. This parameter change enables rapid verification that maintains processing speed while effectively detecting hijacked responses with incorrect timing characteristics.

The patent applies preliminary action by pre-storing card identifiers and pre-calculating expected response time windows before any communication occurs. This advance preparation creates a security barrier that prevents unauthorized access, as hijacked responses lacking the correct timing characteristics will be rejected by the verification mechanism, even though remote access capability is maintained for legitimate cards.

The patent implements feedback through a timing verification mechanism that automatically rejects responses not meeting the expected timing criteria. This feedback loop maintains authorization security by ensuring that only responses with valid timing characteristics (indicating legitimate card-to-reader communication) are processed, while blocking unauthorized access attempts through hijacked or falsified data.