<p>The Internet of Things (IoT) has changed healthcare. It allows better patient monitoring and connects medical devices in Industry 5.0. These advances improve care, but they also raise cybersecurity risks. Sensitive patient data can be exposed if not properly protected, especially when transmitted over public networks. Many authentication protocols have been proposed for secure IoT communication. Traditional one-to-one methods allow access to only one device at a time. This is insufficient when multiple devices require simultaneous access. Healthcare workers need one-to-many authentication. This lets them access all patient devices quickly and monitor effectively. To tackle these issues, we propose an authentication framework (AF) for IoT healthcare systems. It uses authenticated encryption and hash functions. Our AF allows doctors to safely get real-time data from multiple devices on a patient. Mutual authentication is performed first, then session keys are set up with several devices at once. This ensures secure data access from many IoT devices. We checked the security of AF using formal methods. Its resistance to attacks is shown through informal analysis. We also used Scyther to test the framework’s resilience. Finally, we evaluated its efficiency. The framework shows lower communication and computation overhead, while giving strong security protections.</p>