Novel mechanism for anonymous reporting and anonymous rewarding using blockchain technology

A person can report a crime anonymously. However, without sufficient motivation, individuals are reluctant to report the crime. To encourage individuals who can provide evidence of a crime, reporting a crime is closely associated with the rewarding mechanism. Anonymous crime reporting is not a challenging issue. We can use a conventional security mechanism to protect individuals' identities. However, it becomes a challenging issue when the objective is to ensure anonymous crime reporting and anonymous rewarding. With the help of a trusted third-party, such as a security agency, conventional mechanisms collect crime-related evidence and reward whistleblowers. However, a trusted third-party may disclose the whistleblower's identity and become an insider adversary. Therefore, to collect evidence related to a crime and reward anonymous whistleblowers for their services, we need a mechanism that eliminates the requirement of a trusted third-party. In this article, we propose a mechanism for anonymous reporting and anonymous rewarding (ARAR) using blockchain technology. We use the public blockchain to timestamp the collected evidence securely and reward the individuals who first submit the evidence. We evaluated the security strength of the proposed mechanism in the presence of active insider and outsider adversaries. The proposed mechanism is significantly reliable in identifying the order in which the evidence of a crime is reported by individuals and associating individuals with their reported information without revealing their identities. Finally, we analyze the efficiency of the proposed mechanism and provide a prototype implementation. Security and performance analysis shows that the proposed mechanism is secure, privacy-preserving, feasible, and efficient.