Security & testing

Leontief holds user funds, so the bar is: every row in the threat model maps to a named, passing test. Zero untested rows. The suite is 98+ tests across unit, property, integration, golden-vector, and fuzz layers.

Verification layers

• Unit — each contract's entry points, typed errors, auth.
• Property (proptest) — accounting fairness, round-trip ≤ deposited, inflation-attack bound, liquidation rounding and termination. Case counts scale from CI to nightly (Decision #4).
• Golden vectors — a Python decimal generator emits JSON expected values; a Rust loader asserts the contracts reproduce them byte-for-byte. The @leontief/sdk previews are asserted against the same file, so client math can't drift from chain math.
• Integration beats — the five beats run against the full contract graph with a real SEP-8 restricted asset.
• Fuzz — two cargo-fuzz targets (vault sequences, pool sequences) run in the nightly workflow.

Threat tie-out (excerpt)

Threat	Defense	Named test
First-depositor inflation	virtual offset VIRT, zero-share revert	inflation_attack_bounded (property)
Caller lies about amount sent	balance-diff around every transfer-in	deposit_measures_balance_diff
Stale / manipulated price	fail-closed staleness + deviation breaker	get_nav_rejects_stale, override_rearms_after_deviation_halt
Depositor loses value at NAV ≠ 1	value-consistent legs (Decision #3)	golden vault vectors, deposit_fair_at_nav
Unauthorized liquidation	whitelist gate	beat 5b, liquidate_requires_whitelist
Liquidation drains a healthy user	health < 1 guard + close factor	liquidate_only_unhealthy
User trapped during incident	exits never pausable	withdraw_works_while_paused, repay_needs_no_oracle
Rounding leaks value to users	floor → user, ceil → protocol	golden vectors across both legs

The full matrix lives in SECURITY-TESTING.md in the repo.

Golden vectors

The generator (tests/fixtures/golden_gen.py) computes every expected value in Python's arbitrary-precision decimal, writes golden.json, and both the Rust contracts and the TypeScript SDK assert against it. This is what guarantees the three surfaces — spec, contract, SDK — agree to the integer.

Gates & disclosure

• CI gate: just check must be green — fmt, clippy -D warnings, tests, and a coverage floor of ≥ 90% lines on the funds-holding contracts (currently ~95.8%). Red CI never merges.
• Toolchain pinned: soroban-sdk 27.0.0, rustc 1.97.1, wasm32v1-none; never bumped unasked.
• Disclosure: coordinated, 90-day, security@leontief.app. A loss-of-funds report goes straight to the pause playbook — deposits can be halted within the hour, and exits are never paused.