Anonymous Evaluation System

Design and Implementation of an Anonymous and Secure Online Evaluation Protocol

“…In the online educational evaluation system of [17], Attribute Based Credentials [15] were employed to allow students to evaluate, anonymously, the competence of the subjects they have selected. Privacy ABCs, as most anonymous credentials instantiations, rely on user's hardware and employ cryptographic constructs which are considered to be heavy with respect to computation and storage [2,19]. Having said that, in recent years there have been attempts to improve their practicality, e.g., [20,21], however much work is still needed before anonymous credentials are considered practical.…”

“…In the anonymous evaluation system proposed by Kluczniak et al [2], an evaluator i registers her standard DSA public signature keys (in the form of PK i ← g x i ) to the Registration Server (controlled by the University), and then uses her corresponding private keys x i to authenticate their evaluations. To protect the evaluators' anonymity, the Questionnaire Server receives a list of randomized public keys (i.e., a white list), in the form of R(PK i ) ← (g x i ) r , where the randomizing exponent r is the product of powers r j , j = 1, ..., n shared between the Registration Server and several n Mixers (controlled bu the students' Council), where n ≥ 1.…”

“…To preclude cheating by the mixing server, a cut-an-choose, interactive zero-knowledge based protocol is run between the mixing servers and an inspection system. Overall, the scheme proposed by Kluczniak et al [2] is a relatively complex system that achieves most of the security and privacy requirements; however it fails to achieve fairness, i.e., ensure that an evaluator has attended a minimum number of lectures for a specific course. In addition, the assumption that several mixing servers will not collude to violate the evaluators' privacy could be seen as hard.…”

“…During the Covid-19 pandemic, the education sector, across the globe, was forced to adopt remote and online learning technologies, making the process of evaluating the effectiveness of online learning, in all educational stages, quite important [1]. Typical approaches, which involve students filling a web-based questionnaire after being authenticated to the department's or university's MOOC platform fail to protect the privacy of the evaluator or cannot be trusted [2]. Related privacy-preserving methods and technologies (e.g., anonymous credentials [3][4][5]), Privacy Attribute-Based Credentials [6], domain signatures [7], fail to address, at least in an obvious way, the minimal security and practicality requirements.…”