## 1 Introduction  
In recent decades, many developed solutions such as those for smart homes, security surveillance, healthcare, agriculture, etc., have been associated with wireless standards and physical objects. All these applications are designed to ensure trustworthiness, efficient resource management, and on-time data monitoring using IoT networks [1, 2, 3]. However, most of the applications based on IoT sensors only collect and forward the monitored information without guaranteed reliable performance in the event of communication faults or obstacles. The development of wireless sensor networks (WSNs) for medical applications [4, 5, 6] is gaining momentum due to IoT sensors that can track patients' locations and facilitate real-time health monitoring. Many solutions exist in the field of healthcare using IoT systems to support the interaction between physicians and patients while stayingremote [7; 8; 9]. These solutions interact with IoT networks and offer smart communications with faster and intelligent information management. Such solutions not only ease the efforts of medical experts in identifying the diseases of patients but also offer a smart communication system using lightweight devices. They help in communication among patients and medical experts without visiting hospitals or making prior appointments. However, the minimal boundaries for medical sensors in processing, storage, and battery power pose significant research problems for reliable healthcare data transmissions. Additionally, the unpredictable and unfixed communication structure of sensor nodes further highlights the security issues. The medical data are transmitted over a congested, open-air medium. As a result, unknown or malicious observers can compromise the patients' sensitive data [10; 11; 12; 13]. Although many communication models using medical sensors have been developed, several challenges and open research problems are still faced by the research community in terms of communication standards, secure architecture, data reliability, resource management, etc. The reliable and resilient IoT network [14; 15; 16; 17] ensures the ability of the communication system to recover and remain active after being affected by an unexpected incident. It not only continues offering network-oriented services but decreases the probability of data interruption among connected routes. Accordingly, medical applications should be developed with the resilience to improve the performance of wireless technologies and features for network maintenance and high accuracy with secure communication. Moreover, the integrity and privacy of IoT systems with a cloud structure are also necessary to avoid the misuse of the network data and avoid compromising performance [18; 19]. The main contributions of this research work are summarized as follows. 1. It offers bidirectional routes for IoT-based Zigbee medical networks and supports low overhead with a applications interface. Such factors improve reliability and scalability for health devices even under conditions of high data traffic and decrease the convolution factor. 2. It also presents lightweight mutual validation for medical information and supports data privacy among processes using the verified cryptosystem. This component excludes unauthenticated endeavors in the healthcare system with the incorporation of real keys. 3. In the end, the network data is also securely transmitted from the cloud interface to physicians using a hybrid security model and gives resilient trustworthiness. 4. Based on the security analysis and a set of extensive experiments, the proposed approach has demonstrated improved performance against security threats with increasing network reliability. The organization of this research work was prepared as follows. Section 2 presents the literature work with problem findings. Section 3 illustrates the network assumptions and a detailed discussion of the proposed approach. Section 4 presents the security analysis and simulation-based experiments. Finally, Section 5 concludes the research work.