Secure Key Exchange Protocol for Multi-Drop Bus Authentication

The patent implements a preliminary authentication action by establishing a secure key exchange protocol before allowing any communication on the bus. When a device joins the bus, it must first authenticate through polynomial code-based key exchange with existing devices. This preliminary security check ensures that only authorized devices can participate in bus communications, resolving the contradiction by maintaining security reliability while allowing dynamic adaptability.

The patent changes the parameter of authentication from complex multi-step protocols to a streamlined polynomial code-based key exchange. By using mathematical polynomial codes and their roots as authentication keys, the system achieves strong security with simpler operations. The polynomial code parameters (coefficients, roots, finite field elements) provide cryptographic strength while requiring only basic arithmetic operations, thus improving security without proportionally increasing device complexity.

The authentication is performed as a preliminary action during device join or before secure communication sessions, not continuously during data transmission. Once a device is authenticated through the polynomial code key exchange, it can communicate freely on the bus without repeated authentication overhead. This approach ensures unauthorized access prevention while minimizing the impact on communication productivity during active data transfer.