An emerging blockchain protocol design pattern leverages the asymmetry between the computational effort in performing versus verifying tasks. For example, cryptographic validity proofs (e.g., SNARKS) require the prover to expend significant effort demonstrating the correctness of their claim, while the verifiers benefit from extremely easy validation. The operationalization of this paradigm requires efficiently soliciting the performance of expensive tasks in pseudonymous, adversarial environments. We formalize this as a mechanism design question. The protocol balances the economic cost of a liveness fault, where the work is not completed, with the payments required to incentivize specific behavior from candidate suppliers. We show that the loss of the optimal protocol scales logarithmically in the cost of a liveness fault, scaled up by the adversarial fraction of the network. Further, we find that the optimal equilibria have an intuitive structure, allowing us to provide concrete advice to practitioners. Specifically, in many regimes, the optimum designates a single, random node as the primary worker and a committee as a fallback, which is reminiscent of leader-based consensus mechanisms. We also characterize the asymptotic regimes where having negative payments (i.e., slashing in blockchain parlance) is especially helpful.

翻译：新兴的区块链协议设计模式利用了执行任务与验证任务之间计算工作量的不对称性。例如，密码学有效性证明（如SNARKs）要求证明者投入大量计算资源以展示其声明的正确性，而验证者则能通过极简易的验证过程获益。该范式的实现需要在伪匿名、对抗性环境中高效征集昂贵任务的执行。我们将其形式化为机制设计问题：协议需平衡因任务未完成导致的活性故障经济成本，与为激励候选供应商特定行为所需的支付成本。我们证明，最优协议的损失随活性故障成本呈对数增长，且该成本受网络对抗性比例的放大。进一步发现，最优均衡具有直观结构，可为实践者提供具体建议。例如，在许多场景下，最优方案指定单个随机节点作为主要工作者，并设立委员会作为备用方案，这类似于基于领导者的共识机制。我们还刻画了负支付（即区块链术语中的"罚没"）尤为有效的渐进性态区域。