Fog-Assisted Secure Data Exchange for Examination and Testing in E-learning System

E-learning systems are getting growing interest due to their wide applicability in distance education. A huge amount of data is shared among students, teachers, examiners that should be exchanged in a confidential manner. In literature, a number of related clustering-based schemes are explored that consider security but still there is a need for dependable secure schemes. This paper explores a Secure E-learning System (SES) for sharing examinations related materials by ensuring protection against various security attacks. Exam materials include tests, quizzes, question papers, answer sheets, and aptitude tests. In the first phase, we present a secure authentication mechanism for students and teachers with a trusted server or a fog server. Next, we present a Session Key Establishment Protocol (SKEP) to setup keys for a specified time period such as a class, seminar or exam. We have also maintained the level of trust and authentication level to regularly check the legitimacy of the students. A security analysis is performed to highlight the pros and cons of security schemes to ensure reliable security for e-learning systems. We have setup a testbed using web-services in ASP.​net and C# on windows Azure cloud for an e-learning scenario. Results demonstrate the effectiveness of the proposed SES in terms of reducing number of untrusted students, exams exposed, student interaction time, authentication level, reputation and trust levels for students.