Reproducible evidence · July 18, 2026
Retail payment fraud strategy: baseline vs. Titan v2.
We replayed the identical deterministic cohort of 27 synthetic retail-app and tap-to-pay attempts through both policies via /v1/sentinel/evaluate: six labeled fraud attempts and 21 legitimate attempts. This is proof of the shared runtime's test behavior, not a claim of live fraud-loss reduction.
A/B results
| Metric | Baseline v1 | Titan v2 | Delta |
|---|---|---|---|
| Fraud recall | 33.33% | 83.33% | +50.00 pp |
| Simulated fraud value prevented | $2,150 | $3,090 | +$940 |
| Legitimate friction rate | 0.00% | 4.76% | +4.76 pp |
| Flag precision | 100.00% | 83.33% | −16.67 pp |
What changed
Success and failure evidence
Success: Titan v2 stopped three additional labeled fraud patterns and increased prevented synthetic fraud value from $2,150 to $3,090.
False negative: one mature stolen wallet token with otherwise normal telemetry was allowed.
False positive/friction: one legitimate purchase shortly after account recovery received a phishing-resistant step-up challenge.
Mature-token takeover: the next control layer
A mature stolen wallet token can preserve normal device, velocity, merchant, and spending telemetry. That makes it a chain-of-custody problem, not a reason to indiscriminately tighten the existing thresholds.
Planned signals: token issuance and recovery provenance; ownership-continuity drift across device, IP, ASN, carrier, and app telemetry; explicit token→account→canonical-device binding; and issuer/chargeback feedback for delayed labels.
Planned policy: only mature tokens with provenance or continuity anomalies enter a stricter tier, with independent proof of control for high-risk purchases rather than blanket blocking.
Status: designed, not included in the A/B above. It requires wallet-provider/issuer data and a focused privacy-reviewed cohort before enforcement.
How to interpret this proof
Ledger boundary: SQL Server Ledger and similar products provide meaningful tamper evidence within a centrally controlled database. Titan adds portable signed receipts that can be verified outside the originating store, but independent multi-party key custody and external anchoring still require operational validation.
Decision boundary: the current fraud path is constrained, auditable policy over structured transaction, device, wallet, velocity, evidence-freshness, and runtime-health inputs. It is not presented as a high-parameter historical fraud model.
Efficacy boundary: cryptographic integrity proves that a decision record was signed and not altered; it does not prove that the fraud decision was correct. Production claims require representative labeled outcomes and a predeclared evaluation design.
Reproduce it
The public evidence artifact freezes the cohort size, labels, baseline, treatment, deltas, and limitations used by this page. The complete Titan reference implementation remains private, so BrainSignal does not claim that an outside reviewer can rebuild the proprietary policy engine from public source today.
Download the machine-readable evidence · Inspect the public receipt specification · Review current buyer-diligence boundaries
Evidence boundary: deterministic synthetic cohort; no production payment rails, issuer decisions, processor disputes, wallet-provider telemetry, or chargeback labels were used. Thresholds require privacy-reviewed production calibration before enforcement.