Security challenges for workflow allocation model in cloud computing environment: a comprehensive survey, framework, taxonomy, open issues, and future directions

In cloud computing environment, the workflow allocation mainly focuses on task assignment to satisfy the quality-of-service (QoS) standards and workload balancing by the best use of the demanded resources as a service on pay per use basis to optimize objectives from service level agreements. In secured workflow allocation (SWA), the intermediate data transfers in sensitive workflow tasks demand security requirements during the execution across the virtual machines. Security-aware workflow execution challenges result in a significant share of security overhead which affects the QoS performance. The aim of this work is to facilitate the researcher's selection of suitable SWA approaches from the existing approaches in the literature. To achieve this, we have comprehensively reviewed the current state-of-the-art approaches of the SWA models in cloud computing environments. Also, a secured workflow allocation challenges taxonomy by describing the security overhead model and QoS objectives and constraints is presented. Finally, it determines and discusses the existing open issues, challenges, and future research direction in the SWA model based on the study's literature review. The study will help researchers in the domain with current security challenges for SWA research trends.