Abstract

Ratings provided by advisors can help an advisee to make decisions, e.g., which seller to select in e-commerce. Unfair rating attacks—where dishonest ratings are provided to mislead the advisee—impact the accuracy of decision making. Current literature focuses on specific classes of unfair rating attacks, which does not provide a complete picture of the attacks. We provide the first formal study that addresses all attack behavior that is possible within a given system. We propose a probabilistic modeling of rating behavior, and apply information theory to quantitatively measure the impact of attacks. In particular, we can identify the attack with the worst impact. In the simple case, honest advisors report the truth straightforwardly, and attackers rate strategically. In real systems, the truth (or an advisor’s view on it) may be subjective, making even honest ratings inaccurate. Although there exist methods to deal with subjective ratings, whether subjectivity influences the effect of unfair rating attacks was an open question. We discover that subjectivity decreases the robustness against attacks.

Highlights

  • Users can help each other make decisions by sharing their opinions, especially when direct experience or evidence is insufficient

  • We consider two types of ways proposed by system designers to deal with subjectivity: feature-based rating, which is popularly applied in reality to help resolve conflicting emphasis on features in overall rating, and clustering advisors, which is proposed in literature to distinguish advisors with different subjectivity. These approaches aim to mitigate the influence of subjectivity, so it is interesting to study whether they improve the robustness against unfair rating attacks

  • We proposed a quantitative measurement of unfair rating attacks based on information theory

Read more

Summary

INTRODUCTION

Users can help each other make decisions by sharing their opinions, especially when direct experience or evidence is insufficient. Malicious advisors (attackers) may deliberately provide fake or unreliable ratings to impact the decisions of some other users (advisees). This is known as an unfair rating attack. Many approaches have been proposed in the literature to improve the robustness of trust systems against unfair rating attacks. The worst-case scenario for the advisee is that the attack is the one that minimises the information leakage about the facts. Honest advisors can be subjective in rating, or have different preferences from an advisee. Clustering advisors based on their behaviour is another way to discern subjectivity difference. We propose a probabilistic rating model and an informationleakage based quantification method, as a basis of the study on unfair rating attacks throughout the paper. We study whether the existing methods of dealing with subjectivity would influence robustness against attacks

Dealing with Unfair Rating Attacks
Dealing with Attacks under Subjective Rating
PRELIMINARIES
QUANTIFYING ATTACKS UNDER OBJECTIVE RATING
Modeling Objective Rating
Ultimate Attacks
Minimizing Information Leakage
QUANTIFYING ATTACKS UNDER SUBJECTIVE RATING
Modelling Subjective Rating
Information leakage
Quantitative Robustness Comparison
ROBUSTNESS OF EXISTING APPROACHES TO DEAL WITH SUBJECTIVITY
Feature-based rating
Clustering Advisors
CONCLUSION

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.