Strongly Nonoutsourceable Scratch-Off Puzzles in Blockchain
Published in Soft Computing, 2023
Blockchain and its most selling point decentralization have attracted lots of attentions. However, the problem of centralized mining pools (also called outsourcing problem) is a serious threat to the fundamental security of Bitcoin and other blockchains that also use a scratch-off puzzle (Miller et al. in Proceedings of the 22nd ACM SIGSAC conference on computer and communications security, 2015). Although there are some solutions proposing “nonoutsourceable puzzles” to stop the pool operators in the centralized mining pools from outsourcing their mining work to others, we find that none of them can be adopted in real world to support strong nonoutsourceability. In other words, through some special means, e.g., legal prosecution or a tainted public reputation, the pool operator still can outsource his mining work. In this paper, we study the formal definition of strong nonoutsourceability and present constructions that support strong nonoutsourceability. The experimental results also show that our concrete construction is practical.
Recommended citation: G Zeng, Z Huang, Y Wang, X Mu, C Zhang. Strongly nonoutsourceable scratch-off puzzles in blockchain. Soft Computing 27 (17), 11941-11960 (2023).
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