Research Of Trust Evaluation Mechanism In Sensor-cloud Based On Fog Computing

As the interface between human and nature,Wireless Sensor Network(WSN)improves human's ability to perceive and collect external information.However,WSN is deficient in computing,storage and other aspects,and its resource utilization is limited.Cloud Computing has powerful storage,computing,sharing and processing capabilities.Based on the concept of complementary advantages,researchers proposed and constructed the Sensor-Cloud.Sensor-Cloud not only takes full advantages of WSN and Cloud Computing,but also extends many new functions.With the development of Sensor-Cloud,its security problems have been widely concerned.Internal attacks account for a large proportion of all security threats.T he trust evaluation mechanism is an effective solution to internal attacks.Based on the research on existing trust evaluation mechanisms in Sensor-Cloud,we found some problems that need to be solved:1)The existing trust evaluation mechanisms consume too many network resources.Sensors in WSN have some limitations in terms of energy,storage space,and computing power.Trust evaluation mechanisms will consume plenty of sensor resources,which reduces the performance and lifetime of WSN.2)The existing trust evaluation mechanisms pay more attention to trust at the behavior level,which is not effective in detecting internal attacks at the data level.Some malicious sensor nodes in WSN is not to destroy the network or steal data,but to guide users to make wrong decision by generating wrong data.These attacks seriously threaten the service quality of Sensor-Cloud.3)How trust evaluation mechanisms improve the security and efficiency of Sensor-Cloud services.With Sensor-Cloud popular,the number of repeat/similar requirements increases.If Sensor-Cloud processes these requirements individually,it will be inefficient.For non-real-time applications,the problem of service efficiency is not obvious.For applications that need to interact with WSN in real time,it is an urgent problem to be solved.It is a good idea to move the high resource consumption part of trust evaluation mechanism to the cloud.However,the cloud is far away from WSN,which can cause significant delay.Fog Computing is a computing mode extended from Cloud Computing,which is closer to the underlying network and has certain computing,storage and processing capabiliti es.Therefore,this paper proposes to establish a support platform and service access point based on Fog Computing,which provides a safe and efficient service environment for Sensor-Cloud.In this paper,Fog computing is designed as the buffer layer of WSN and cloud,so as to establish,manage and maintain the trust relationships.The main research work is as follows:1)Solving the problem that trust evaluation mechanism s consume more underlying network resources.Based on Fog Computing,the trust evaluation mechanism is designed into a hierarchical structure.This structure is used to transfer the high resource consumption part of trust evaluation mechanism to the fog layer to reduce the resource consumption in the underlying network.2)Solving the problem of detecting internal attacks at the data level.Fog Computing is built into two parts: fog network and fog platform.Fog networ k assists WSN to establish trust in the underlying network.When the detection cycle comes,fog platform analyzes the sensor data collected by the underlying network,so as to discover the internal attacks at the data level.3)Solving the security and efficiency of Sensor-Cloud services.The parameter template and the parsing template are built for Sensor-Cloud services,and fog platform is taken as the service access point.The parameter template digitizes user requirements and reduces data transfer.The parsing template is related to the application execution,reducing application preparation before execution.The trust evaluation mechanism is used to establish the parsing template and guarantee the reliability of sensor data.To sum up,aiming at the shortcomings of existing trust evaluation mechanisms in Sensor-Cloud,this paper designs a trust evaluation mechanism framework based on Fog Computing.Based on this framework,the hierarchical trust evaluation mechanism,the internal attack detection mechanism at the data level,and the secure and efficient IoT-Cloud(Sensor-Cloud)service structure are realized.Based on Fog Computing,the high resource consumption part of trust evaluation mechanism in WSN is transferred,and a safe and efficient service environment is established.