Security seal

Security seals are mechanisms used to seal shipping containers in a way that provides tamper evidence and some level of security. Such seals can help to detect theft or contamination, either accidental or deliberate. Security seals are commonly used to secure truck trailers, vessel containers, chemical drums, airline duty-free trolleys and utility meters. Typically they are considered an inexpensive way of providing tamper evidence of intrusion into sensitive spaces.

Vulnerabilities

Security seals are not designed to resolve all security problems:

The same organization demonstrated that a trained individual was able, using low-tech methods, to defeat 90% of the 244 seals they studied in less than 3 minutes, and all of them in less than 44 minutes. They offer ideas on countermeasures, and are exploring the promising option of "anti-evidence" seals.

Operation

Security seals can be split into two main groups: single use and reusable. Single use seals are typically made of plastic or metal, and the used material and production technology is the key to their security level. Reusable seals are usually electronic or mechanical rather than just made from plastic, and if purely plastic, only one part is reusable. Electronic and mechanical seals are generally used for the transportation industry, with seal fixed to the back of trucks, trailers and shipping containers. A reusable mechanical or electronic seal can be fitted to the rear or loading doors, extending a cable from itself through fixing points on the doors, and when sealed generating a unique number which is logged. When the door is next opened this number changes, so it provides tamper evidence for the load.