Abstract:

Web services are effective ways to invoke resources in cloud computing. A single web service often has limited functions and can only accomplish specific tasks. Service composition can make Web services form an effective call sequence and achieve more powerful functions. The rapid growth of service publishing and service requests has brought new security problems. First of all, the existing service composition schemes are based on QoS for web service selection, but the QoS value usually provided by the services publisher, and there is a certain fraud phenomenon: the service publisher publishes false QoS value to lure users. Secondly, the traditional service composition scheme only generates an optimal path, when malicious requests continue to visit, and this will cause a service node to be paralyzed, or even the whole service composition system to fail. Therefore, in order to solve the problem of QoS malicious fraud, we propose a trusted QoS computing model, which comprehensively evaluates QoS value according to the credit of the web service publisher. To solve the problem which a single optimal path cannot satisfy a large number of requests, a multipaths method of path discovery and load balancing is proposed. Simulation results show that the method proposed in this paper can not only improve the success rate of service composition, but also find more execution options of service composition schemes.

Key words: service composition, QoS model, load balancing, service classes