Online Advertising with Verifiable Fairness

Online advertising is a popular business model where advertisers can deliver promotional marketing messages to their potential consumers via Ad brokers. However, as the proxy between advertisers and customers, a malicious Ad broker could arbitrarily fabricate the advertising rates to overcharge advertisers, which causes unnecessary financial loss. To deal with this issue, we propose a publicly verifiable and fair online advertising scheme. Specifically, a proof-of-downloading (PoD) protocol is first designed based on the zero-knowledge succinct non-interactive argument of knowledge (zk-SNARK), to help the customer generate a unique acknowledgment for downloading the Ad; the acknowledgment will then be published to both the advertiser and the Ad broker such that anyone can verify the acknowledgment to guarantee the fairness and transparency of online advertising. Moreover, as long as the customer's private key is not leaked, our scheme can resist the collusion attack, i.e., the Ad broker and the customer collude with each other to deceive the advertiser, which has not been addressed in previous works. Finally, we evaluate the performance of the proposed scheme to demonstrate its computational efficiency.