Enhancing Cryptocurrency Blocklisting: A Secure, Trustless, and Effective Realization

The flourishing development of blockchain and cryptocurrency has made it a hotbed for cyber-criminals to implement virtually untraceable scams. Consequently, the blockchain ecosystem urgently needs an effective method to help users stay away from scams in order to create an enticing investment environment. Despite the massive deployment of blocklist query APIs for malicious and scam domains/URLs in the industry, we identify two core reasons why existing blocklist services find it difficult to thrive in the cryptocurrency paradigm: 1) the compelling need to protect a user query due to sensitivity and high value of query content, i.e., payment addresses; 2) the thorny issue of evaluating the quality of blocklists effectively, in the face of common practices of incompetent providers.
To this end, we first provide a private and highly efficient blocklist query scheme as a basic design, which conveniently achieves backward compatibility with current blockchain payment systems at a considerably low cost. Based on this design, we propose a new framework for shareholders to evaluate the quality of blocklists. Our framework provides stronger security guarantees than other similar works, as it is capable of suppressing both individual biasing and coercive manipulation at the same time. We provide a complete game-theoretic analysis and demonstrate comprehensive evaluation results to confirm the effectiveness and efficiency of our solutions, under the settings of a practical number of shareholders.