Security assessment
The independent assessment of the on-chain contracts, and how its findings were handled.
The Cross-Chain Swap Engine's on-chain contracts were assessed by CertiK on June 22, 2026, with the final report published June 25, 2026. The assessment was a manual review covering the Ethereum HTLC and fee-registry contracts and the Canton-side swap flow — SwapRequest through HashedTimeLock to HTLCLock — together with the Amulet adapter.
This page summarises the outcome. It is not an attestation of security, and it is not a substitute for your own review.
Findings summary
The assessment recorded 15 findings:
Critical
1
Major
1
Medium
1
Minor
9
Informational
3
Of these, 13 were addressed in commits and 2 findings were acknowledged.
The two acknowledged findings
Both acknowledged findings are informational.
A superseded backing hold is not released in-protocol
When a Canton lock's backing hold is refreshed — for example after a routine rotation of the underlying asset — the prior hold is not released by the protocol itself. It stays owned by the locker and is reclaimed after the lock's deadline through the reference tooling. This does not affect the user-facing funds. An in-protocol release is not possible under the underlying lock's rules, so this was acknowledged and handled off-ledger rather than in the contract.
The Ethereum-leg fee is resolved at lock time
The Ethereum side reads the platform fee from the on-chain fee registry when a swap locks, rather than binding the fee to the quote. If the registry rate changes in the short window between quote and lock, the lock either applies the changed rate or — if it would exceed the fee ceiling the user consented to — reverts. The user-consented fee cap bounds the exposure: a higher rate can never be applied silently. Binding the Ethereum-leg fee to the quote was acknowledged, with the user-consented fee cap as the durable protection and an off-ledger synchronisation mitigating drift between quote and lock.
The report
The full CertiK report and project page are available at:
https://skynet.certik.com/projects/interstice-digital
Where to next
Security model — the mechanisms the assessment reviewed.
Failure modes — what each break point looks like.
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