## 3 Q2: What Are the Challenges of the Current UIoT System
### Security Goals, Attacks and Privacy of UIoT
#### 3.4.1 Security Goals of UIoT  
It is classified into two parts (1) primary security goals and (2) secondary security goals [42; 43; 44]. Integrity, confidentiality and availability are the three primary security goals of UIoT, expected to be available in all UIoT applications. On the other hand, privacy, synchronization, authenticity, quality of service, auditability, accountability and secure localization are the secondary security goals of UIoT. The classification of UIoT security goals are described underneath.  
ConfidentialityIn UIoT networks, confidentiality is the essential feature for securing underwater data. A key sharing mechanism is a suitable approach that can be utilized to protect the data during transmission. In addition, for confidentiality, an auto-decision-making mechanism must be used for storing and retrieving data in the UIoT environment [42].  
IntegrityIn UIoT networks, data integrity is essential to maintain the accuracy and reliability of underwater data. Data integrity refers to the approaches to check whether the received data are altered during transmission via an underwater channel. For example, a message integrity check (MIC) can be used to verify the data integrity of received underwater data. In addition, an auto-integrity-checking mechanism such as logs integrity and software integrity can be used to verify the integrity of log reports and device software, respectively, in the UIoT environment [42].  
AvailabilityIn UIoT networks, data availability is necessary to provide the quality of services such as preventing UIoT devices from malicious attacks, securing harbor environment, securing diverse life at risk, etc. Self-healing, auto-recovery and centralized data sharing functions are necessary to support availability in UIoT networks [42].  
PrivacyIn UIoT networks, privacy refers to the information or service that a particular user or device can access. As discussed in Section 3.3.2, it is difficult to adapt the existing privacy  
Figure 5: Goals and classification of security attacks in the UIoT environment.  
approaches directly to UIoT networks. Hence, it is necessary to port a robust privacy approach for UIoT to protect the data from attackers. The types of privacy approaches that need to be considered in UIoT are categorized underneath:  
_UIoT data privacy:_ In UIoT networks, data privacy is necessary in naval applications to protect secret messages from attackers, e.g., enemy submarine attacking and secret message passing.  
_UIoT device privacy:_ In UIoT networks, a device identity is generally used to track and transfer information to UIoT devices. This identity is traceable; therefore, it is easy for the attackers to steal the information. In this case, a robust identity protection approach is necessary to hide the device identity from malicious nodes.  
_UIoT location privacy:_ In UIoT networks, location information is necessary to track the mobility of UIoT devices. The location information is open and is essential for data transmission between the nodes in the underwater environment. In addition, hiding the location of nodes based on necessity is a challenging task. Hence, it is necessary to port a privacy-based location sharing mechanism for UIoT devices.