swIDch M2M Authentication is a machine-to-machine authentication solution designed for IoT and industrial automation environments. The product uses One-Time Authentication Code (OTAC) technology to secure communication between devices such as sensors, gateways, robots, and machines in smart factory settings. The solution generates dynamic, non-duplicating codes that change with each authentication attempt. These codes are generated client-side without requiring server communication, enabling authentication in offline or networkless environments. Each device receives a unique code that identifies it without requiring traditional static credentials like IDs and passwords. The system addresses replay attacks and impersonation attacks common in M2M communications. It provides unidirectional authentication flow, reducing round trips in device-to-device communication. The technology supports distributed authorization through passport OTAC, which combines user authentication and role-based authorization information with digital signatures. The authentication codes are designed to be sufficient for device identification on their own, eliminating the need for additional static information exchange. The solution is intended for Industry 4.0 manufacturing environments where multiple machines coordinate production activities through direct communication.