PTP Switch Timestamp Filtering for Secure One-Way Data Transmission

The patent introduces a gateway device as an intermediary between the secure site (OT network) and unsecure site (IT network). This gateway acts as a mediator that filters and validates data packets using timestamps, allowing legitimate data transmission while blocking malicious information. The gateway device with timestamp validation mechanism resolves the contradiction by enabling productivity improvement through controlled data transmission while maintaining security reliability through active filtering of unauthorized packets.

The patent uses timestamp as a key parameter for validating data packets. By changing the validation approach from complex content analysis to simple timestamp comparison, the system achieves improved security reliability with minimal increase in complexity. The gateway device compares timestamps in incoming packets against expected time ranges, providing an efficient filtering mechanism that balances security enhancement with system simplicity.

The patent implements preliminary timestamp validation on data packets before they are allowed to pass from the secure site to the unsecure site. This preliminary action of timestamp checking is performed in advance during maintenance operations, ensuring that only packets with valid timestamps (and thus legitimate source identification) are transmitted. This approach maintains ease of operation for authorized maintenance while preventing malicious virus transmission by blocking unauthorized packets before they can reach the unsecure site.