The most successful methods of attack on sealing systems are those exploiting the weaknesses of the sealing system rather than the tamper-indicating seal itself. A sealing system would fail at the seal if the seal could be opened and re-closed without leaving any marks to indicate tampering. A sealing system that depends on blank seals being unavailable to the adversary can fail if the supplier of the seals or one of his employees can be persuaded to provide replicates to a diverter. This type of failure presupposes a weakness in the identification of the seals. Therefore, all users of seals should require assurance from the manufacturer of the seals that the seals are unique, that the seals will not be supplied to other users, and that the masters will be controlled. Security seals also do not allow the information taken and recorded at the time of seal application is inadequately protected, enabling a diverter to forge documentation to support or cover the diversion.