With the development of quantum computers, the public blockchain based on traditional elliptic curve digital signature will face disruptive security issues. The common solution is to apply post-quantum digital signature algorithms to blockchain systems. For the public blockchain adopting proof-of-work consensus mechanism, supporting computing power is also an important cornerstone of public blockchain security. How to save energy and maximize computing power support is an important research direction. This article proposes a post-quantum blockchain system with diversified computing power and independent post-quantum signature.
The Dilithium signature scheme is the preferred and universal post-quantum signature standard recommended by the NIST, and its security is based on the MLWE and MSIS problems on the power-of-two division ring. However, just as the Bitcoin blockchain initially adopted the EC-DSA standard signature algorithm but did not adopt the elliptic curve specified by the US NIST, the rich algebraic structure of the power-of-two cyclotomic rings poses greater risks and uncertainties for the long-term security of the post-quantum digital signatures on which the public blockchain is based. Large-Galois-group prime-degree prime-ideal field is a more conservative and secure post-quantum lattice-based cryptographic technology route with fewer algebraic structures. In this article, we adopt a Dilithium variant based on large-Galois-group prime-degree prime-ideal field: Dilithium-Prime, as the signature algorithm for the post-quantum blockchain system to provide high-confidence transaction signing post-quantum security.
To provide diversified computing power to maximize the computing power support of the post-quantum public blockchain and address the current dilemma of declining mining pool and miner income, we introduce a multi-parent chain auxiliary proof-of-work consensus mechanism that can request all computing power using Sha256 and Scrypt hash calculations to assist in consensus without adding additional work to existing miners and mining pools. This increases the source of computing power for the post-quantum blockchain and also improves the utilization rate of existing mining pools and miners. At the same time, we propose a block and transaction structure and difficulty adjustment algorithm adapted to this multi-parent chain auxiliary proof-of-work consensus mechanism, which can stabilize the block production ratio and block production time for different magnitudes of computing power, and effectively responding to extreme cases such as sudden increases or decreases in computing power to maintain the robustness of the system.