@toon-protocol/settlement-digest

Dependency-light leaf for the RollingSwapChannel v2 EIP-712 balance-proof digest and the Solana / Mina balance-proof message digests, plus pure EVM signer recovery. Its only runtime dependencies are @noble/hashes and @noble/curves — no ethers, no ABI libraries, no @toon-protocol/core.

This package is the single source of truth for the digest bytes that every signer and verifier in the TOON ecosystem depends on:

• @toon-protocol/core / @toon-protocol/sdk (adopt-and-re-export)
• the swap payment-channel signer
• the toon-client settlement leg
• the connector's off-chain inbound verifier

It was extracted (Phase 1 of connector#329) from @toon-protocol/core (settlement/hashes.ts) and @toon-protocol/sdk (settlement/evm.ts) with no behavior change — the golden vectors in docs/rolling-swap-v2-digest-spec.md §4 reproduce byte-for-byte.

API

Byte helpers: hexToBytes, bigintToBytes32BE, concatBytes.

EVM v2 EIP-712 digest: eip712DomainSeparatorEvm, balanceProofHashEvm, coopCloseHashEvm, plus the *_TYPEHASH / DOMAIN_*_HASH constants.

Non-EVM message digests: balanceProofHashSolana, minaHashToField, balanceProofFieldsMina.

Pure recover/verify (plain params + a 65-byte r||s||v signature): recoverEvmSigner(digest, sig65), recoverEvmClaimSigner(params, sig65), verifyEvmClaimSignature(params, sig65, expected) — plus the EvmClaimDigestParams type.

The v2 digest

domainSeparator = keccak256(abi.encode(
  EIP712DOMAIN_TYPEHASH, keccak256("RollingSwapChannel"), keccak256("2"),
  chainId, verifyingContract))
structHash      = keccak256(abi.encode(TYPEHASH, fields...))
digest          = keccak256(0x1901 || domainSeparator || structHash)

chainId + verifyingContract are folded into the signed preimage so a claim signed for one (chainId, contract) pair can never be replayed on another (refs connector#324 finding #1).