Smart contracts in the Ethereum system are stored tamper-resistant, complicating necessary maintenance for offering new functionalities or fixing security vulnerabilities. Previous contract maintenance approaches mainly focus on logic modification using delegatecall-based patterns. While popular, they fail to handle data state updates (like storage layout changes), leading to impracticality and security risks in real-world applications. To address these challenges, this paper introduces SmartUpdater, a novel toolchain designed for transparent, automated, and secure maintenance of stateful smart contracts. SmartUpdater employs a hyperproxy-based contract maintenance pattern, where the hyperproxy serves as a constant entry and ensures that any state/logic modifications remain transparent to end users. SmartUpdater automates the maintenance process in terms of development streamlining, gas cost efficiency, and state migration verifiability. In extensive evaluations, we show that SmartUpdater can reduce gas consumption in contract maintenance compared with actual maintenance approaches. The evaluations point out the potential of SmartUpdater to significantly simplify the maintenance process for developers.

In the trend of network middleboxes as a service, enterprise customers adopt in-the-cloud deep packet inspection (DPI) services to protect networks. As network misconfigurations and hardware failures notoriously exist, recent efforts envision to ensure the execution integrity of DPI services in untrusted clouds. However, they either require enterprise customers to know proprietary DPI rulesets of cloud providers or introduce forbidden overhead in the network context. In the paper, we propose a privacy-preserving and lightweight verification scheme that efficiently checks whether in-the-cloud DPI services run correctly without leaking private DPI rulesets. Particularly, our design introduces one trusted third party to perform privacy-preserving and trustworthy ruleset evaluation and DPI execution verification. Meanwhile, it devises a novel DPI ruleset authentication method that enables tamper-proof DPI operations and facilitates fast proof generation. The proofs can be verified without requiring the verifier to always maintain all rulesets. To further reduce the verification costs while resisting cloud cheating behaviors like bias treatments of packets, it employs a commitment-based delayed sampling mechanism which requires the DPI services to first demonstrate that all packets have been processed before receiving sampling decisions. Moreover, extensive experiments are conducted based on Click modules. The results show that the proposed scheme is practical and only incurs the real-time overhead of 10–20 microseconds.