> For the complete documentation index, see [llms.txt](https://quantumwing.gitbook.io/quantumwing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://quantumwing.gitbook.io/quantumwing/smart-contracts/verification.md). # Contract Verification Source-code verification for QWVM and EVM contracts Verification associates a contract's deployed bytecode with the source code that produced it. Once verified, the explorer renders the source inline and exposes a function-level UI for read/write calls. ## Backend The beacon API (`blockchain/api/contract_verification.go`) registers: ``` POST /api/v1/contract/verify # submit source for review GET /api/v1/contract/{address}/verification # verification record GET /api/v1/contract/{address}/source # source code only ``` Submission body: ```json { "address": "0xfbe6fdad648b861ad8fed358a3985c3fbba58de5", "source_code": "", "compiler_version": "solc 0.8.24+commit.e11b9ed9", "optimization": "yes,200", "constructor_args": "0x...", "bytecode_hash": "", "submitted_by": "0x..." } ``` Acceptance criteria: ``` 1. Address resolves to a deployed contract. 2. submitted bytecode_hash == on-chain contract.BytecodeHash 3. source_code, compiler_version, bytecode_hash all non-empty. ``` A successful submission stores a `VerifiedContract` record, which the explorer subsequently surfaces. The API does NOT compile source itself; it trusts the submitter's declared `bytecode_hash` and rejects on mismatch. ## Frontend The explorer flow lives at `explorer/app/contracts/[address]/verify/page.tsx` (commit `809d7dd95`). Page layout: ``` 1. Address banner ← GET /api/v1/contract/{address} 2. Form - Source code (multiline, monospace) - Compiler version (dropdown — solc / qwvm-rust / qwvm-asc) - Optimization settings - Constructor args (hex) 3. Submit button → POST /api/v1/contract/verify 4. Result panel (success/failure + bytecode hash diff) ``` After submission, the contract detail page renders: ``` ∎ Verified ✓ ← top-right badge Source code (collapsible) ABI (decoded) Read functions (UI: input fields + "Query") Write functions (UI: input fields + "Send") ``` ## Bytecode-hash derivation ``` QWVM (WASM): bytecode_hash = SHA3-256(wasm_bytes) EVM (Solidity): bytecode_hash = SHA3-256(deployedBytecode) ``` The `deployedBytecode` (not `creationBytecode`) is the runtime image loaded by the VM. Tools that hash creation bytecode will fail verification — match the on-chain blob exactly. ## Reproducible builds For Solidity: ```bash solc --optimize --optimize-runs 200 \ --combined-json bin-runtime,abi MyContract.sol > out.json jq -r '.contracts[].bin-runtime' out.json | xxd -r -p | sha3sum -a 256 ``` For QWVM (Rust → WASM): ```bash cargo build --release --target wasm32-unknown-unknown sha3sum -a 256 target/wasm32-unknown-unknown/release/my_contract.wasm ``` ## Verifying a contract end-to-end ```bash # 1. Deploy ./build/quantum-wing-blockchain contract deploy \ --wasm my.wasm --from 0xe20E... --gas 1000000 # Output: Contract Address: 0xfbe6f... # 2. Compute bytecode hash locally HASH=$(sha3sum -a 256 my.wasm | awk '{print $1}') # 3. Submit verification curl -X POST http://localhost:8080/api/v1/contract/verify \ -H 'Content-Type: application/json' \ -d "{ \"address\": \"0xfbe6f...\", \"source_code\": \"$(cat my.rs | jq -Rs .)\", \"compiler_version\": \"rustc 1.75.0 (wasm32-unknown-unknown)\", \"optimization\": \"release\", \"bytecode_hash\": \"$HASH\", \"submitted_by\": \"0xe20E...\" }" # 4. Render in explorer open https://explorer.quantumwing.io/contracts/0xfbe6f... ``` ## Limitations * No automated re-compilation (yet). Operators trust the submitter's declared `bytecode_hash`; mismatches are rejected at submission, but a malicious submitter could publish source that does NOT correspond to the bytecode if their hash happens to match. Mitigation: explorer badges "Verified by" and surfaces the submitter address. * No multi-source / library linking UI. * No ABI auto-derivation — the explorer parses ABI from the source block on render. ## Code paths * `blockchain/api/contract_verification.go` — REST handlers + storage * `explorer/app/contracts/[address]/verify/page.tsx` — submit form * `explorer/app/contracts/[address]/page.tsx` — verified-source render * Commit `809d7dd95` — initial verification flow ## Related * [qwvm.md](/quantumwing/smart-contracts/qwvm.md) — QWVM contract bytecode layout * [wasm-gas-metering.md](/quantumwing/smart-contracts/wasm-gas-metering.md) — WASM execution * [../EVM\_INTEGRATION\_ROADMAP.md](https://github.com/dolfrin/QuantumWing/blob/master/docs/EVM_INTEGRATION_ROADMAP.md) — Solidity status --- # Agent Instructions This documentation is published with GitBook. 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