By Jennifer Zaino

Oct. 12, 2009—Whether you're a manufacturer, logistics provider or port operator involved with the transportation of cargo by ship, rail or truck, you're likely familiar with the practice of securing containers or vehicles with tamper-indicating seals. Today, thousands of available commercial seals—either mechanical or electronic—can indicate whether a door was opened without authorization. But that's where the similarity among these seals ends.


Mechanical seals employ simple bolt or cable-lock mechanisms to obstruct the opening of cargo containers or vehicle doors. While a broken seal makes it obvious that a breach has occurred, it's possible for the bolt or lock to be removed and replaced without the shipper's knowledge.

Electronic seals (e-seals) include physical protection, such as a bolt, as well as a sensor that can monitor for tampering, or some other electronic way to ensure goods are protected. For example, some e-seals can be opened only with a corresponding electronic key received over high-security data links at the destination site. Some can send data about potential tampering and where it might have occurred via a GPS (global positioning system) in combination with satellite or cellular networks, before cargo is loaded into a carrier, en route at sea, and after it arrives at its destination.