COoL-TEE: Client-TEE Collaboration for Resilient Distributed Search

Abstract: Current marketplaces rely on search mechanisms with distributed systems but centralized governance, making them vulnerable to attacks, failures, censorship and biases. While search mechanisms with more decentralized governance (e.g., DeSearch) have been recently proposed, these are still exposed to information head-start attacks (IHS) despite the use of Trusted Execution Environments (TEEs). These attacks allow malicious users to gain a head-start over other users for the discovery of new assets in the market, which give them an unfair advantage in asset acquisition. We propose COoL-TEE, a TEE-based provider selection mechanism for distributed search, running in single- or multi-datacenter environments, that is resilient to information head-start attacks. COoL-TEE relies on a Client-TEE collaboration, which enables clients to distinguish between slow providers and malicious ones. Performance evaluations in single- and multi-datacenter environments show that, using COoL-TEE, malicious users respectively gain only up to 2% and 7% of assets more than without IHS, while they can claim 20% or more on top of their fair share in the same conditions with DeSearch.