# Fraud-Proof 欺诈证明 ## 设计目标 * **不需要每笔 tx 都立即验证**：减少 gas 成本 * **任何人都可以反证**：去中心化（permissionless） * **作弊有经济代价**：50% slash share + 7 天 window * **诚实 aggregator 几乎零成本**：只承担 stake 锁仓机会成本 ## 状态机 ``` ┌──────────────┐ │ open() │ challenger 付 BOND_AMOUNT (0.1 ETH) │ │ 提交 Merkle proof + fraud claim ▼ │ ┌──────────────────────────┐ │ │ Status.Pending │ │ └────┬──────────────┬──────┘ │ │ │ │ respond() │ │ 7 days passed aggregator│ │ 提交反证 │ │ ▼ ▼ ┌─────────────────────┐ ┌─────────────────────────────┐ │ Status.ResolvedNoFr │ │ Status.ResolvedFraud │ │ (challenger 作弊) │ │ (aggregator 作弊) │ │ challenger bond → treasury │ aggregator full slash │ │ │ │ → StakeManager.treasury │ └──────────┬──────────┘ └──────────────┬──────────────┘ │ │ claim() │ │ claim() ▼ ▼ ┌─────────────────┐ ┌──────────────────────────┐ │ Status.Claimed │ │ Status.Claimed │ │ treasury 收 bond │ │ challenger: bond 退回 │ │ │ │ + 50% slashed reward │ └─────────────────┘ └──────────────────────────┘ ``` ## ChallengeManager 完整接口 ```solidity interface IChallengeManager { function open( uint256 batchId, uint32 leafIndex, BehaviorEventView calldata event_, bytes32[] calldata merkleProof ) external payable; function respond( uint256 challengeId, BehaviorEventView calldata event_, bytes32[] calldata merkleProof ) external; function resolveExpired(uint256 challengeId) external; function claim(uint256 challengeId) external; function getChallenge(uint256 challengeId) external view returns (Challenge memory); function isPending(uint256 batchId, uint32 leafIndex) external view returns (bool); } ``` ## 关键参数 ```solidity // ChallengeManager.sol uint256 public constant CHALLENGE_WINDOW = 7 days; uint256 public constant BOND_AMOUNT = 0.1 ether; uint256 public constant CHALLENGER_REWARD_BPS = 5000; // 50% uint256 public constant BPS_DENOM = 10000; ``` ## 8 类可检测的 Fraud baby-pob-challenger 的 `FraudDetector` trait 当前实现 8 种检测： | # | Fraud type | 检测方法 | | - | -------------------------------------------------------------- | ----------------------------- | | 1 | header.agentId ≠ leaf.agentId (header lying about which agent) | 抽样 leaf 反查 | | 2 | leafCount 与实际 leaf 数不符 | 重算 merkle root 不一致 | | 3 | merkleRoot 不可重建 | 重算不一致 | | 4 | timestamp 早于上一个 batch | 单调性检查 | | 5 | spec\_hash 引用不存在 | BehaviorSpecRegistry.exists 查 | | 6 | aggregator 已被 deactivate 但仍 submitBatch | StakeManager.activeStake 查 | | 7 | event 引用未注册的 spec | BehaviorSpecRegistry 查 | | 8 | event 的 outcome 与 BehaviorSpec evaluation 不一致 | OPA Rego 重评估 | 实际 chain 391 真链 e2e 用了 #1。 ## Rust Challenger Daemon 架构 ```rust // baby-pob-challenger/src/daemon.rs pub struct ChallengerDaemon where W: BatchWatcher, D: FraudDetector, O: ChallengeOpener, { watcher: W, detector: D, opener: O, cursor: AtomicU64, // 已处理的 batchId 上限 poll_interval: Duration, } impl ChallengerDaemon { pub async fn tick(&self) -> DaemonReport { let batch_count = self.watcher.get_batch_count().await?; let mut report = DaemonReport::default(); let from = self.cursor.load(SeqCst); for id in from..batch_count { report.batches_seen += 1; let batch = self.watcher.get_batch(id).await?; match self.detector.detect_fraud(id, &batch).await? { DetectionResult::NoFraud => {}, DetectionResult::Fraud(claim) => { self.opener.open_challenge(claim).await?; report.fraud_detected += 1; report.challenges_opened += 1; } } self.cursor.store(id + 1, SeqCst); } report } pub async fn run_until_shutdown(&self, shutdown_signal: impl Future) { loop { tokio::select! { _ = shutdown_signal => break, _ = tokio::time::sleep(self.poll_interval) => { let _ = self.tick().await; } } } } } ``` 详见 [B4-Phase2 Challenger Daemon devlog](https://github.com/leeleeEcho/babyDriver_Layer2/blob/main/docs/devlog/2026-Q2/2026-04-30-DAY-SUMMARY.md#6-b4-phase2-challenger-rust-daemon-commit-1f1e29d)。 ## 真链 e2e 跑通记录 (commit 023f7aa) 5 笔关键 tx： ```bash # 1. aggregator deposit 0.5 ETH stake cast send $STAKE_MANAGER "deposit()" --value 0.5ether \ --private-key $AGGREGATOR_KEY # 2. submit fraud batch (header.agentId = 0x97f8..., leaf.agentId = 0xd983...) cast send $POB_REGISTRY "submitBatch((bytes32,...))..." \ --private-key $AGGREGATOR_KEY # 3. challenger open challenge with Merkle proof + 0.1 ETH bond cast send $CHALLENGE_MANAGER "open(uint256,uint32,...)" \ 0 0 "(0xd983...,...)" "[0x...,0x...]" \ --value 0.1ether --private-key $CHALLENGER_KEY # 4. evm_increaseTime 7 days + 1s (anvil-zksync test 用) cast rpc evm_increaseTime 604801 # 5. resolveExpired → 真 slash 0.5 ETH cast send $CHALLENGE_MANAGER "resolveExpired(uint256)" 1 \ --private-key $ANYONE_KEY # 6. challenger claim → bond return + reward cast send $CHALLENGE_MANAGER "claim(uint256)" 1 \ --private-key $CHALLENGER_KEY ``` 完整 deployment JSON: `deployments/b4p2-fraud-proof-e2e-chain-391.json` (gitignored)。 ## 已修真 bug — CEI Violation **slither 发现**：`resolveExpired` 中 `c.status = ResolvedFraud` 写在 `stakeManager.slash()` 外部调用之**后**，违反 Checks-Effects-Interactions。 **修复** (commit `7a1c8b5`)： ```solidity // Before (vulnerable): stakeManager.slash(c.accusedAggregator, active); // Interaction slashed = active; c.status = Status.ResolvedFraud; // Effects 太晚 // After (CEI compliant): uint256 slashed = active; // Checks c.status = Status.ResolvedFraud; // Effects c.resolvedAt = uint64(block.timestamp); _slashedAmount[challengeId] = slashed; emit ChallengeResolved(...); if (active > 0) { stakeManager.slash(c.accusedAggregator, active); // Interaction 最后 } ``` `forge test --match-contract ChallengeManager` 31 tests 全过。详见 [审计预审报告](https://github.com/leeleeEcho/babyDriver_Layer2/blob/main/docs/audit/pre-audit-self-review-2026-05-07.md)。 ## Invariant Suite (16 properties × 256 fuzz runs) ```solidity // test/Challenge.invariant.t.sol contract ChallengeInvariantTest is StdInvariant, Test { // I1: 任何 challenge 的 bond 必须 ≥ 0.1 ETH function invariant_bondNeverBelowMin() public { ... } // I2: 任何 ResolvedFraud 必须有 _slashedAmount > 0 当 active stake > 0 function invariant_slashConsistency() public { ... } // I3: 任何 status=Claimed 必须 _claimed[id] = true function invariant_claimedFlag() public { ... } // I4-I16: ... } ``` 完整 16 个 invariant 跑过 256 round fuzz 全通过。 ## 相关 * [Slash 经济学](/algorithms/slash-economics.md) — 经济参数校准 * [Positional Merkle Tree](/algorithms/merkle-tree-positional.md) — 反证算法 * [Examples → Open Challenge](/integration-jie-ru-fang-shi/examples/open-challenge.md) — 实操示例 * [B4-Phase2 W1-W4 devlog](https://github.com/leeleeEcho/babyDriver_Layer2/tree/main/docs/devlog/2026-Q2) — 4 周开发历程 --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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