The receipt
✓ HOLDS
A permanent, tamper-evident record of a verification. The content hash IS the proof — re-fetch it and the bytes must match, or it is not this record.
Worked trail
CONFIRMED Luhn([CARD_1]) is valid
doc_validation.luhn: Luhn '4532015112830366' valid=True (matches claim)
CONFIRMED ISBN-13 978-0-306-40615-7 is valid
doc_validation.isbn13: ISBN-13 '9780306406157' valid=True (matches claim)
gates
RED:PASS
content hash (the seal)
c7afd6622e881c44def4bb5327d8928d81bba9c5199dcfa0f2ee5b6f728b9992
raw JSON ↗ · re-check: GET /seal?hash=c7afd6622e881c44…