PoW (Proof of Work) plays a significant role in most blockchain systems to grant an accounting right over decentralized participants and ensure tamper resistance. Though hash functions are generally exploited for PoW due to their merits on summering, anti-collision, and irreversibility, they cannot certify that the bookkeeper is exactly the worker. Thereafter, such insistence may lead to abuse or even embezzlement of computing power for the benefit of malicious miners. To preserve the functionality of PoW but also bind the miners’ signing keys with their works, we build a post-quantum PoW scheme by changing the approximate closest vector norm for probabilistic NTRUSign. Different from the schemes based on hash functions, our scheme takes signing as the proof of work where signature verification is just the evidence of block reward. We also presented a method to adjust the difficulty of signing by modifying the probability of generating a correct signature. The performance of our scheme is also analyzed theoretically and experimentally, which implies its practicability and advantages.

Proof of work; NTRUSign; Burr distribution; blockchain