An Efficient and Collusion-Resistant Key Parameters Predistribution System for Day-Ahead Electricity Auctions

In recent years, extensive research has been conducted on the design of electricity auctions. However, most existing solutions focus mainly on privacy preservation, efficiency, and bidding strategies, while overlooking the critical issue of key parameters distribution—particularly in day-ahead electricity auctions. At the start of an auction, it is essential to distribute key parameters to all participants in a timely, synchronized, and efficient manner. To address the challenges of fairness, collusion resistance, and efficiency in the pre-distribution of key parameters, we propose an efficient and collusion-resistant key parameters pre-distribution system for day-ahead electricity auctions. As a core component, we design a novel cryptographic primitive, termed identity-based timed-release proxy re-encryption. Based on the truncated q-ABDHE hardness assumption, we instantiate two concrete schemes tailored to different security requirements. The proposed schemes eliminate the need for public key authenticity verification, support efficient privilege revocation, and provide resistance against proxy-bidder collusion attacks. Additionally, the schemes feature user-scale-independent key and ciphertext sizes, leading to significantly improved system efficiency compared to existing approaches.