Architecture

Components

  Ethereum Sepolia (source, chain key 1)        Creditcoin CC3 Testnet (102031)
  ┌───────────────────────────────┐             ┌──────────────────────────────────┐
  │ EnergyMeter.sol               │             │ EnergyProofConsumer.sol          │
  │  recordProduction(EnergyParams)│            │  is AttestcoinReader             │
  │  emits EnergyProduced(        │             │  execute(chainKey, block, ...)  │
  │    oracle, producer,          │             │   1. computeQueryId              │
  │    readingId, wattHours)      │             │   2. reject if processed (replay)│
  └──────────────┬────────────────┘             │   3. VERIFIER.verifyAndEmit(...) │
                 │                              │   4. decode tx (EvmV1Decoder)   │
                 │  (1) tx + event log          │      require receiptStatus == 1 │
                 ▼                              │      find EnergyProduced log    │
  ┌───────────────────────────────┐             │      require source == METER    │
  │ worker/watch.ts               │             │   5. bounds-check wattHours     │
  │  poll EnergyProduced          │  (4) submit │   6. LEDGER.credit(...)         │
  │  generateProofFor(txHash) ────┼────proof───▶ └──────────────┬──────────────────┘
  │   - wait attested height      │                            │
  │   - proofBuilder.getProof     │             ┌──────────────▼──────────────────┐
  │  submit to consumer.execute   │             │ EnergyCreditLedger.sol          │
  └───────────────┬───────────────┘             │  credit(producer, wh, readingId,│
                  │                             │         queryId) onlyConsumer   │
                  │  (2) GET proof              │  settled[readingId] guard       │
                  ▼                             │  balanceOf[producer] += wh      │
  ┌───────────────────────────────┐             │  emits SettlementRecorded      │
  │ Attestcoin proof builder      │             └────────────────────────────────┘
  │ prover.cc3-testnet...         │
  │ + NativeQueryVerifier 0x..0FD2 │  (3) attestation reached on Creditcoin
  └───────────────────────────────┘

Flow (happy path)

1. An oracle calls EnergyMeter.recordProduction(EnergyParams) on Sepolia. The contract emits EnergyProduced(msg.sender, producer, readingId, wattHours).
2. worker/watch.ts sees the event, takes the tx hash, and calls the Attestcoin SDK: wait until the Sepolia block height is attested on Creditcoin (~8 min), then proofBuilder.getProof(txHash) returns { chainKey, headerNumber, txBytes, merkleProof, continuityProof }.
3. The worker calls EnergyProofConsumer.execute(uint64 chainKey, uint64 blockHeight, bytes encodedTransaction, tuple merkleProof, tuple continuityProof) on Creditcoin with that proof data.
4. AttestcoinReader computes queryId (chainKey|blockHeight|txIndex), rejects a replay, calls the 0x..0FD2 precompile verifyAndEmit, and requires it to return true.
5. EnergyProofConsumer decodes the verified transaction bytes with EvmV1Decoder: requires receiptStatus == 1, finds the EnergyProduced log by signature, requires the emitting contract to equal the configured energyMeter address, and extracts (oracle, producer, readingId, wattHours) from the log topics/data.
6. It bounds-checks wattHours (0 < wattHours <= MAX_WATT_HOURS) and calls EnergyCreditLedger.credit(producer, wattHours, readingId, queryId, chainKey, blockHeight).
7. The ledger checks !settled[readingId], sets it, increments balanceOf[producer], stores structured settlementOf(readingId) data including source chain/block provenance, and emits SettlementRecorded.

Trust model

• No trust in the worker. The worker only relays bytes; it cannot forge a credit. Every field the ledger acts on comes from a transaction the Attestcoin precompile has verified as included in an attested Sepolia block.
• No trust in the caller of execute. Anyone may submit a valid proof; the proof is self-authenticating. Griefing (submitting someone else’s proof) only credits the rightful producer sooner and burns the caller’s gas.
• Two independent replay guards. AttestcoinReader.processedQueries[queryId] (one reading per source transaction) and EnergyCreditLedger.settled[readingId] (per meter reading).
• EnergyCreditLedger.credit requires CONSUMER_ROLE. Direct settlement is impossible.
• Meter onboarding is permissioned. Register separates the admin, registrar, and oracle roles. This controls who may submit source readings; it does not replace Attestcoin proof verification.

Why this fits DePIN

EnergyMeter stands in for a metering device / sensor on one network; settlement and incentive accounting happen on Creditcoin, driven entirely by cross-chain data that Attestcoin has attested. The cross-chain decision does not trust a centralised relay; source-reading submission is separately controlled by the meter’s ORACLE_ROLE.