ERA: Towards Privacy Preservation and Verifiability for Online Ad Exchanges

TL;DR

ERA introduces a privacy-preserving and verifiable online auction mechanism for ad exchanges, ensuring auction correctness and bidder privacy with efficient cryptographic protocols, suitable for real-world deployment.

Contribution

The paper presents ERA, a novel online auction scheme combining privacy preservation via order-preserving encryption and verifiability through a new protocol based on Paillier encryption.

Findings

ERA achieves low overheads in computation, communication, and storage.

The protocol guarantees auction correctness and bidder privacy.

Performance evaluations confirm ERA's practicality for real-world ad exchanges.

Abstract

Ad exchanges are kind of the most popular online advertising marketplaces for trading ad spaces over the Internet. Ad exchanges run auctions to sell diverse ad spaces on the publishers' web-pages to advertisers, who want to display ads on ad spaces. However, the parties in an ad auction cannot verify whether the auction is carried out correctly or not. Furthermore, the advertisers are usually unwilling to reveal their sensitive bids and identities. In this paper, we jointly consider the auction verifiability and the advertisers' privacy preservation, and thus propose ERA, which is an Efficient, pRivacy-preserving, and verifiAble online auction mechanism for ad exchanges. ERA exploits an order preserving encryption scheme to guarantee privacy preservation, and achieves verifiability by constructing a novel protocol of privacy preserving integer comparison, which is built on the Paillier homomorphic encryption scheme. We extensively evaluate the performance of ERA, and our evaluation results show that ERA satisfies several desirable properties with low computation, communication, and storage overheads, so ERA can be easily deployed in today's ad exchanges.