Abstract
With the significant popularity and utility, the web services have uniquely emerged as a new paradigm shift to many enterprises such as banking, government applications, telecom sectors and other solution providers. When web services are integrated with cloud services, web services achieve more flexibility and performance. Hence, through a web service, a mobile phone user can upload sensitive documents to cloud and share them with employees and customers, but the security in the cloud is yet to be completely resolved. Recently, the authors Zhu and Jiang have securely shared group keys among cloud users without secure communication channels. But, we have recently proved that, the existing method is susceptible to man-in-the-middle attack and message modification attack. A new protocol termed as MGPV has been proposed in this research work which averts all the possible attacks. It minimizes the computation complexity and ensures that the documents are accessible only by valid group users. It ensures that even the group manager and the cloud cannot access the documents stored in the cloud. The experiments conducted on the mobile cloud environments reveal that this protocol is worthy of implementation in the real world scenarios. (C) 2019 Elsevier B.V. All rights reserved.