## 2 Related Work and Design Challenges
### Privacy Preservation and Design Objectives  
In WSN applications like WBANs (wireless body area networks), privacy, secure authentication, and authorization of patients' information are in high demand. WBANs include emerging widespread wireless sensor network applications, especially in intelligent WSN healthcare applications. Secure authentication and authorization ensure that collected, stored, and transmitted data cannot be accessed and modified by unauthorized agents in networks, such as cyber hackers. Privacy preservation ensures that only authorized agents can access and use data in the network. Consequently, it becomes imperative to address authentication, authorization, and privacy protection concerns for WBANs [34].  
Cyber hackers could launch various attacks, specifically cyberattacks, including sinkhole node and sibyl node attacks, that could breach healthcare data privacy. Healthcare data privacy is a significant issue leading to the need for protection in wireless sensor networks. Therefore, we focus on the data privacy protection issue resulting from cyberattacks, including sinkhole node and sibyl node attacks that can occur during healthcare WSN patient information monitoring. Cyber threats, including sinkhole node attacks, are internal attacks that compromise network nodes. As a result, compromised or vulnerable sensor nodes (SNs) attempt to attract all network traffic from the neighboring sensor nodes and generate fake routing metrics. Cyber threats resulting from sinkhole node attacks cause routing information issues such as acknowledgment spoofing and selective forwarding attacks. They can also send simulated data to the base station.  
Conversely, cyber threats resulting from sybil node attacks sabotage the reputation of hop-to-hop communication systems, generating many fake identities. Sybil node cyberthreats happen after sinkhole node attacks, so both attacks rely on each other. We assume hackers understand the deployed security mechanism in the wireless sensor networks. Therefore, hackers may be able to compromise a node by applying a radio communication channel at the medium access control (MC) sublayer. After compromising the node, the attacker launches the sinkhole node cyber threats that release privacy data to the cyber enemies, compromising any individual sensor node privacy. The public key cryptographic authentication technique can secure ad hoc networks. Still, it is not compatible with wireless sensor networks due to the highly resource-constrained attributes of the sensor node.  
The proposed SDAAA protocol guarantees energy efficiency and reliability, and the scalable, secure data communication process in this research model leads to privacy preservation in the network. Consequently, the design objectives of the proposed SDAAA approach are to obtain energy efficiency and fast data aggregation with maximum throughput while maintaining data privacy as a tradeoff. As presented in this research, the proposed SDAAA approach depends on the authentication process that helps maintain node authorization security and ensures privacy in the WBAN healthcare system. Our proposed paradigm considers accuracy as a standard for gauging authentication performance and energy efficiency.  
Therefore, we provide a new system design and mathematical analytical secure data aggregation model to reevaluate new network QoS performance as required.