Security model and residual risk boundaries

Security objective

The objective is deterministic integrity of settlement-critical transitions under realistic adversarial conditions. Security is evaluated as a full lifecycle system, not only as smart-contract correctness.

A useful model separates enforced guarantees from operational assumptions so stakeholders can reason about risk without ambiguity.

Assets and invariants

Security testing should assert these invariants across unit tests, integration suites, and projection pipelines.

• Locked value paths and final settlement outputs.
• Role-bound transition rights tied to signer identity.
• Close reason and terminal economics integrity.
• Consistency of lifecycle state across chain and indexer surfaces.

Primary adversary classes

• Counterparty adversary exploiting economic asymmetry.
• Key-compromise adversary attempting unauthorized actions.
• State-race adversary abusing stale reads and ordering assumptions.
• Infrastructure adversary causing observability degradation.

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Control layers

No single layer should carry all trust. Durable posture comes from layered controls with clear responsibilities.

• Protocol layer: deterministic transition and authorization checks.
• Indexer layer: idempotent ingestion and replay safety.
• Application layer: explicit state rendering and safe action gating.
• Operations layer: monitoring, runbooks, and escalation discipline.

Authorization and signer integrity

Role checks must bind directly to signer authority in each instruction path. Client-side assumptions are insufficient for security-critical behavior.

Rejected authorization attempts should be observable and classified for abuse monitoring.

State-transition integrity

Most exploit surfaces in settlement systems involve state confusion. Strong transition integrity rules reduce that class of failure significantly.

• Validate preconditions against current on-chain state.
• Disallow transitions from stale or incompatible states.
• Prevent duplicate or contradictory terminal actions.
• Persist transition evidence for replay and audit.

Operational security posture

Security posture includes release discipline, dependency hygiene, environment hardening, and incident readiness. Critical paths should have explicit ownership and response expectations.

• Structured release checklists for high-risk changes.
• Alerting on anomalous transition and close behavior.
• Regular tabletop exercises for incident response readiness.