ODYSSEY: Reestablishing Confidentiality in Confidential Blockchain via Delegated Execution
2026-06-03 • Cryptography and Security
Cryptography and Security
AI summaryⓘ
The authors study confidential blockchains that use special hardware called Trusted Execution Environments (TEEs) to keep transactions private. They identify two types of attacks that exploit weaknesses in TEEs to break confidentiality. To address these, they designed ODYSSEY, a system where clients let trusted parties execute transactions, and others only see the results, reducing risks and keeping performance high. The authors tested ODYSSEY on an enterprise blockchain and showed it handles thousands of transactions quickly and securely.
Confidential BlockchainTrusted Execution Environment (TEE)Execution-inference attackExecution-replay attackConsortium BlockchainTransaction ConfidentialityDelegation ModelConcurrent ExecutionFISCO BCOSThroughput and Latency
Authors
Ju Yang, Weili Wang, Jianyu Niu, Jianzong Wang, Yinqian Zhang
Abstract
Confidential blockchains leveraging Trusted Execution Environments (TEEs) have garnered extensive attention for transaction confidentiality. In this paper, we first taxonomize two classes of attacks against confidential blockchains, i.e., execution-inference and execution-replay attacks, which exploit TEEs' long-lasting side-channel and state-continuity issues to compromise the confidentiality of existing consortium blockchains. Then, we present ODYSSEY, a confidential blockchain that efficiently mitigates these attacks. The core innovations of ODYSSEY are the following: (1) Its delegation model: clients delegate transaction execution to their designated trustees, while other participants synchronize only the execution results, which significantly reduces the attack surface while preserving confidentiality and system performance. (2) Two novel techniques to improve ODYSSEY's efficiency and security: location-aware concurrent execution and delegation failure handler. Finally, we develop a prototype of ODYSSEY on FISCO BCOS, an enterprise-grade consortium blockchain platform. We have conducted various experiments, and our evaluation results show that in a WAN environment with 3 nodes, ODYSSEY can achieve about 4k throughput while keeping latency as low as 0.4-0.5s.