Pilote · revue C2PA · Corée mars 2027 · Japon juin 2027 · droit coréen

Numbers appear only with their measurement conditions, and these rows are never merged into one score. Ledger: Closed (permissioned) ledger. No public blockchain is used.

We manage this record ourselves; no outside party monitors it.

Records are anchored to a closed ledger operated by XenLook.

Crystal is an internal virtual currency and cannot be exchanged for cash. Nothing is written to public chains such as Bitcoin.

1. Rotating or cropping a photo breaks fingerprint matching

Rotate 5° · TPR at Hamming ≤ 5: 0% (2000 pairs) Evidence
Center crop 80% · TPR at Hamming ≤ 5: 0% (2000 pairs) Evidence
JPEG q70 · TPR at Hamming ≤ 5: 99.850% (2001 pairs) Evidence
Resize 0.5 · TPR at Hamming ≤ 5: 38.731% (2001 pairs) — 99.85% at Hamming 40 Evidence

2. Negative-set false-positive rate reached its operating point

100k negative-set FPR check: done (100000 pairs) · FPR 0.006% / target 0.01% Evidence
Legacy agentId folder labels · Hamming 40: 0.293% (100000 pairs) · FPR 0.293% / target 0.01% — Pairs where copies of the same portrait were counted as different people Evidence

3. Collusion guarantee covers a single colluder only (c ≥ 2 not guaranteed)

Collusion bound c0 (32 users · 256 bits · η=0.01): 1.7927 Evidence
Collusion bound c0 (64 users · 256 bits · η=0.01): 1.7204 Evidence
False-accusation example with 2+ colluders (plain-language case, n=32, mean of 10 users): 33% Evidence
Product guarantee: c=1 only — VideoSeal is fixed at 256 bits; c=2 would need 319 bits.

4. Adversarial transforms (rotation combos, re-encoding chains)

Attacker-designed transforms; existing benchmarks not overwritten: Fingerprint rotation/combination TPR 0% (40 images). JPEG chain TPR 100%. Watermark rotate_5 bit_match 0.8359375 (S2-aligned detection; the disclosed T6 value 0.496 is a different row) — Original art31 and pdq-roc results are not overwritten; differing values are recorded only in this file Evidence

5. Formats other than photos

Past measurement rows for non-photo formats: 0 — The 2026-08-21 MP4 snapshot is row 6; watermark not applicable
Reader API without login (POST /api/reader/axes): Open (returns verdict evidence) · home upload screen is members-only

6. No external verification yet

WebTrust: Readiness partly complete · internal readiness 75% · no external audit started Evidence
HSM: Intermediate CA key held in Cloud KMS HSM · root key not in an HSM (internal score 50%) Evidence
Key ceremony: Internal record only · no external witness

Claims we do not make: Passed WebTrust · Trust List–listed CA · Externally witnessed key ceremony completed · External VC issuance

7. Not on the C2PA Trust List

C2PA Trust List status: not listed

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