2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95829Sealing information means making it publicly available, but with the possibility of knowing if it has been read. Commenting on [1], we will show that perfect quantum sealing is not possible for perfectly retrievable information, due to the possibility of performing a perfect measurement without disturbance, even on unknown states. The measurement is a collective one, and this makes the protocol of quantum sealing very interesting as the only example of the power of collective measurements in breaking security.6 pages, accepted for publication in International Journal of Quantum InformationQuantum Physicstext