A Universally Composable Non-interactive Aggregate Cash System

【Author】 Jia, Yanxue; Sun, Shi-Feng; Zhou, Hong-Sheng; Gu, Dawu

【Source】ADVANCES IN CRYPTOLOGY- ASIACRYPT 2022, PT I

【影响因子】

【Abstract】Mimblewimble is a privacy-preserving cryptocurrency, providing the functionality of transaction aggregation. Once certain coins have been spent in Mimblewimble, they can be deleted from the UTXO set. This is desirable: now storage can be saved and computation cost can be reduced. Fuchsbauer et al. (EUROCRYPT 2019) abstracted Mimblewimble as an Aggregate Cash System (ACS) and provided security analysis via game-based definitions. In this paper, we revisit the ACS, and focus on Non-interactive ACS, denoted as NiACS. We for the first time propose a simulation-based security definition and formalize an ideal functionality for NiACS. Then, we construct a NiACS protocol in a hybrid model which can securely realize the ideal NiACS functionality in the Universal Composition (UC) framework. In addition, we propose a building block, which is a variant of the ElGamal encryption scheme that may be of independent interest. Finally, we show how to instantiate our protocol, and obtain the first NiACS system with UC security.

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【发表时间】2022

【收录时间】2023-05-05

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