Validators on generic Proof of Stake chains earn the same fees whether they handle attestation work correctly or selectively censor it. For chains whose main activity is moving tokens around, that indifference is fine. For chains whose primary economic activity is recording attestations (content provenance, AI-output attribution, threshold-signed credentials, supply-chain receipts), the indifference becomes a problem. Proof of Useful Attestation (PoUA) makes attestation handling first-class in the consensus weighting itself. Validator vote weight is the product of bonded stake and a reputation scalar in [r_min, r_max] that accumulates from valid attestation work. The reputation update is additive, fee-weighted, non-transferable, and capped per epoch. We prove a cost-to-grind floor (Lemma 1): under chain-wide adaptive burn fraction tau_burn, the non-recoverable cost an adversary pays to inflate reputation by Delta_r is bounded below by tau_burn * Delta_r / (eta * alpha_eff). Under the recommended v0 calibration (r_max/r_min in [4, 10]), the cost premium against a capital adversary is 4x to 10x over equivalent pure-stake PoS at steady state. The paper specifies the mechanism, six layered Sybil and grinding defenses, empirical Monte Carlo strategy-search across the full layered defense, and grinding detectors with explicit threshold derivations. It is a mechanism-design proposal with a formal economic floor and inherited BFT safety and liveness, not a complete cryptographic security proof. This release incorporates feedback from Jiangshan Yu (University of Sydney) and Marko Vukolić (Bitcoin Scaling Labs).

翻译：在通用权益证明链上，验证者无论是否正确处理证明工作还是选择性审查，都能获得相同费用。对于以代币转移为主要活动的链而言，这种无差异性尚可接受；但对于主要经济行为是记录证明（包括内容溯源、AI输出归属、阈值签名凭证、供应链收据）的链，这一无差异性就成了问题。有益证明（PoUA）将证明处理纳入共识权重的第一级考量。验证者的投票权重由质押金与一个位于[r_min, r_max]区间内的声誉标量相乘得到，该标量通过有效的证明工作逐步积累。声誉更新遵循加法规则、按费用加权、不可转移且每个纪元设有上限。我们证明了代价磨耗下限（引理1）：在链级自适应销毁比例τ_burn下，攻击者为将声誉提升Δ_r而支付的不可回收成本下限为τ_burn * Δ_r / (η * α_eff)。在推荐v0校准参数（r_max/r_min ∈ [4,10]）下，针对资本充裕的攻击者，稳态时其成本溢价较同等纯权益证明机制高出4至10倍。本文详细阐述了该机制、六层防女巫与磨耗攻击防御体系、跨全层次防御的实证蒙特卡洛策略搜索，以及带有显式阈值推导的磨耗检测器。这是一项机制设计提案，具备正式的经济下限并继承拜占庭容错的安全性与活性，而非完整的密码学安全证明。本版本融合了悉尼大学余江山与比特币扩容实验室Marko Vukolić的反馈意见。