MGPV: A novel and efficient scheme for secure data sharing among mobile users in the public cloud

Highlights

• Proposed a scheme for secure data sharing among mobile users in the public cloud.

• Designed a collusion aware document storage technique to prevent various attacks.

• Minimized the computational complexity incurred during the upload and download of documents.

• Introduced a protocol to ensure the document confidentiality between data owner and data users.

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.

Introduction

With the advent of customized web services, mobile phones and cloud storage, the secure sharing of sensitive documents among mobile users has become very common now-a-days [1], [2], [3], [4], [5], [6], [7]. It is more convenient for a mobile user to share a document with his peers through a web service. Because of the ubiquitous use of mobile phones and cloud computing, this scheme of sharing documents among the mobile user community is increasing exponentially day by day. In a typical context, a manager of a reputed company may want to share some sensitive documents with the employees of his company. Obviously, the manager would prefer to store the document from his mobile into the cloud using a web service due to the elastic nature and ease of use of cloud and web services [3], [4], [8], [9]. Though a web service is a viable option for mobile users to upload the documents, the documents if stored in a private file server, may need consistent support from maintenance personnels and security experts. But, if the user uploads a file to cloud storage, then the server maintenance and security issues are performed by cloud service providers. Additionally, the flexibility in computing, storage and licensing issues are vested with the cloud service providers themselves. Thus, web services when integrated with cloud services complement each other and emerge as a more powerful paradigm to solve the document storage and retrieval purposes.

Since the present day android powered mobile phones come with more than 2 GB of RAM and 2 GHz of computational capability, access to web services and storage applications in the cloud have become very handy [10], [11], [12], [13], [14]. Hence, if a web service is available, a manager (cloud user) shall upload the business related documents to the public cloud not only for easy storage and retrieval purposes, but for their sharing among other users as well [15].

In such a scenario, though many users attempt to utilize the sharing facilities through public cloud servers, attacks on the cloud storage by hackers and other fraudsters seem to be increasing in the recent past. It can be seen that, the attacks on the cloud and web services have been a matter of common scenario [16], [17], [18], [19], [20] which are yet to be completely resolved [21], [22]. Moreover, a mobile phone user can create hypersensitive documents through a web application. These documents are hosted in the cloud service which could be shared with their peer employees and valuable customers. In connection to this, since the data to the cloud passes through a public channel, the security concern is usually compromised in certain situations. Therefore, the clear idea and motivation behind this research work aims at resolving such security issues.

In this context, Zhu and Jiang in 2016 have proposed a collusion resistant scheme which enables the secure document storage and sharing among the members of a dynamic group in the public cloud [23]. They claimed that, without employing the secure communication channels, they can securely transfer the keys to the group users.

An attacker can make use of Man-in-the-Middle (MITM) attack and the message modification attack as cited in [24] to break the scheme proposed by Zhu and Jiang in [23]. Hence, in this research work, we have taken the attacks on the Zhu and Jiang’s work into consideration and proposed a novel collusion aware protocol which can be employed in a mobile user environment for enabling the mobile users to share documents through the public clouds without the fear of being fiddled with by attacker.

Following are the objectives of this novel research work. (1) To propose a novel collusion aware document storage technique called Modified Group key Protocol Version (MGPV) based on Zhu and Jiang’s scheme [23] which is free from MITM attack, message modification attack and other possible attacks, (2) To minimize the computational complexity incurred during the upload and download of document in the cloud server, (3) To introduce a novel protocol which ensures the document confidentiality between data owner and mobile cloud users even restricting the group manager and the cloud server from accessing the document.

The rest of this research contribution has been organized in such a way that Section 2 surveys the recent works in line with the proposed work which strive to share the data among other users in the cloud environments. The merits and limitations of the protocols under consideration have been analyzed. Section 3 presents the proposed protocol in the context of mobile cloud users and the cloud storage. Section 4 analyses the proposed protocol against the possible attacks and Section 5 provides a detailed discussion of the results obtained during the implementation of this research work. Finally, Section 6 concludes this research work.