Sealed-bid auctions play a crucial role in blockchain ecosystems. Previous works introduced viable blockchain sealed-bid auction protocols, leveraging timed commitments for bid encryption. However, a crucial challenge remains unresolved in these works: Who should bear the cost of decrypting these timed commitments? This work introduces a timed commitment outsourcing market as a solution to the aforementioned challenge. We first introduce an aggregation scheme for timed commitments, which combines all bidders' timed commitments into one while ensuring security and correctness and allowing a varying number of bidders. Next, we remodel the utility of auctioneers and timed commitment solvers, developing a new timed commitment competition mechanism and combining it with the sealed-bid auction to form a two-sided market. The protocol includes bid commitment collection, timed commitment solving, and payment. Through game-theoretical analysis, we prove that our protocol satisfies Dominant Strategy Incentive Compatibility (DSIC) for bidders, Bayesian Incentive Compatibility (BIC) for solvers, and achieves optimal revenue for the auctioneer among a large class of mechanisms. Finally, we prove that no mechanism can achieve positive expected revenue for the auctioneer while satisfying DSIC and Individual Rationality (IR) for both bidders and solvers.

翻译：密封投标拍卖在区块链生态系统中扮演着关键角色。先前的研究已提出可行的区块链密封投标拍卖协议，其利用定时承诺对投标进行加密。然而，这些工作仍有一个关键挑战未得到解决：谁应承担解密这些定时承诺的成本？本研究引入定时承诺外包市场作为上述挑战的解决方案。我们首先提出一种定时承诺聚合方案，该方案将所有投标人的定时承诺合并为一个，同时确保安全性与正确性，并允许投标人数目可变。接着，我们重塑拍卖方与定时承诺求解方的效用函数，设计了一种新的定时承诺竞争机制，并将其与密封投标拍卖结合，形成一个双边市场。该协议包含投标承诺收集、定时承诺求解与支付三个阶段。通过博弈论分析，我们证明该协议对投标人满足占优策略激励相容性，对求解方满足贝叶斯激励相容性，并在大类机制中为拍卖方实现最优收益。最后，我们证明不存在任何机制能在同时满足投标人与求解方的占优策略激励相容性与个体理性的前提下，为拍卖方带来正期望收益。