# Client-Aware Negotiation for Secure and Efficient Data Transmission
## 1 Introduction
### Background and Motivation  
In Wireless Sensor Networks (WSNs), encryption is usually used to ensure the integrity and security of data transmission. We can consider an application scenario where multiple levels of secure data transmission strategies are set for different sensors to reduce the cost of security control, thus reducing node energy consumption and ultimately prolonging the lifetime of the WSN. Meanwhile, the server in server clusters can set the different security strength for different transmissions to reduce the resource consumption of the server. When the load of the server cluster is reduced, power consumption can be reduced by shutting down the machine. In WSNs, many studies are related to energy saving transmission. We can combine these approaches to apply the Client-Aware Negotiation for Secure and Efficient Data Transmission (CAN-SEAT) strategy. [PERSON] et al. [1] designed an energy-efficient routing protocol to extend the lifetime of a WSN called LEACH-VH, which can save energy using selective sleeping nodes and backup nodes. [PERSON] et al. [2] focused on two main optimization problems in WSNs: energy-efficient clustering and routing. They used an efficient particle encoding scheme and a multi-objective fitness function to solve the routing and the clustering problems by load balancing the energy conservation of the nodes. [PERSON] et al. [3] considered that the hybrid Software-Defined Wireless Rechargeable Sensor Networks (SDWRSNs) will last for a long time and introduced an Energy-saving Traffic Scheduling (ETS) algorithm to improve the energy efficiency of this network. [PERSON] et al. [4] were motivated by the requirement of heterogeneity in the Internet of Things and discovered several regularities. [PERSON] et al. [5] studied data gathering problems. Specifically, they optimized the joint application of compressive sensing and network coding by optimally constructing forwarding trees to carry compressed data to projection nodes. Afterwards, [PERSON] et al. [6] used a sparse random matrix as the sensing matrix to solve the issue of compressive sensing. At the same time, they greedily constructed a sequence of a data gathering tree to collect linearly combined measurements, and their method was proven to be near-optimal. [PERSON] et al. [7] creatively presented a design principle called talk more listen less to reduce idle-listening in neighbor discovery protocols. They designed an energy-efficient asynchronous neighbor discovery protocol named Nihao for both symmetric and asymmetric cases. The CAN-SEAT strategy is also applicable to the server cluster, and it can be combined with the server's energy-saving approach described below. [PERSON] et al. [8] proposed a strategy that switches servers between on and sleep in groups based on multi-server vacation queuing theory. [PERSON] et al. [9] provided a model to manage the energy consumption of the server via load-dependent server activation and sleep modes. They defined a multi-server queuing model controlled by a finite state machine to analyze the energy efficiency and performance. Numerical result were provided, and the applicability of the model was proven. [PERSON] et al. [10] studied the queuing system of a data center. They provided two methods for active thresholds to minimize power consumption depending on the current queue size relative to the threshold, and the data center switches specific groups of servers to on or off. To implement client-aware secure transmission, the ideal approach is to achieve customization, i.e., to modify both the client and the server. However, in the actual deployment process, the client is often difficult or impossible to modify. For example, when the client accesses the server through the browser, due to the variety and version of the browser and as the browser has become general software, the CAN-SEAT strategy can only be deployed on the server in this case. However, servers using the HTTPS protocol currently do not provide support for client-aware secure transmission.