Security & audits

Unstable runs the engine proven by its predecessor desk — 1,809 settled trades, ~240 ETH of volume, zero fund-safety incidents— ported to USDC and re-audited from scratch. The full audit lineage lives in the repository's git history.

Audit record

• Pre-deploy: a line-by-line external audit plus an adversarial multi-agent panel (reentrancy, accounting/conservation, blacklist paths, premium math, settlement atomicity, access control) — both returned GO with zero must-fix findings, with a delta re-audit of every applied hardening fix.
• Post-deploy: the deployed runtime bytecode of all four contracts was matched byte-for-byte against the audited source, every constructor parameter verified on-chain, and real-USDC drills exercised fill, settle, refund, self-refund, cancel and recovery paths to the exact cent.
• Continuously: 65 contract tests including conservation invariants (thousands of randomized operations with blacklist chaos), plus keeper and interface suites, run in CI on every change. No contract change ships without a fresh GO.

The invariants, in plain words

• A pending payment can only ever reach the committed maker + fee wallet, or come back to you. There is no third destination in the code.
• The escrow's balance always equals what it owes: open offers + live reservations + pull balances. To the unit.
• No state exists from which funds are unrecoverable by someone's unilateral action — yours (self-refund, withdraw) or the operator's recovery backstop.

Contracts (verified on-chain)

Per-market addresses are identical on both chains (fresh deployers at nonce 0); every id is salted with the chain id and contract address, so the legs can never be confused.

Key discipline

• The owner key is cold — separate from the settlement keys since the moment of deployment, never on a server. It has never signed a transaction.
• Settlement (keeper) keys can't steal: they can only move escrow along the committed path, and they are rotatable by the cold owner on suspicion.
• All money movement is ERC-20 USDC — no native-value paths exist in the contracts.

The USDC caveat

USDC is centrally issued: Circle can blacklist addresses. Escrow payouts survive that (they park in a pull balance — see the refund guarantee). The one risk no USDC-holding contract can engineer away is Circle blacklisting an escrow address itself; we monitor for it operationally, and it has no precedent against neutral settlement infrastructure.