## Cryptology ePrint Archive: Report 2020/844

Generic Superlight Client for Permissionless Blockchains

Yuan Lu and Qiang Tang and Guiling Wang

Abstract: We conduct a systematic study on the light-client protocol of permissionless blockchains, in the setting where full nodes and light clients are rational. In the game-theoretic model, we design a superlight-client protocol to enable a light client to employ some relaying full nodes (e.g., two or one) to read the blockchain. The protocol is generic'', i.e., it can be deployed disregarding underlying consensuses, and it is also superlight'', i.e., the computational cost of the light client to predicate the (non)existence of a transaction in the blockchain becomes a small constant. Since our protocol resolves a fundamental challenge of broadening the usage of blockchain technology, it captures a wide variety of important use-cases such as multi-chain wallets, DApp browsers and more.

Category / Keywords: applications / Blockchain, light client, game-theoretic security

Original Publication (with minor differences): An abridged version of this paper will appear in the 25th European Symposium on Research in Computer Security (ESORICS) 2020.