Sealing the Box

The seal is an obvious target in the challenge to secure the supply chain and the Federal Highway Administration’s Office of Freight Management and Operations, all part of the US Department of Transport (DOT), has published some useful material on the subject as part of its Intermodal Freight Technology programme.

Its report stresses that electronic seals can only be part of a layered approach to security since they are not sufficient on their own.

It is essential to precede the sealing process with business practices and tools that assure the integrity of the container loading and sealing process, says the introduction. In addition, it is helpful – especially for efficiency and productivity – if electronic seals are part of a harmonized and standard international process. From a productivity perspective, electronic seals should be viewed as part of a management visibility and control system, not simply as a security tool.

Electronic seals tend to combine physical seals and RFID components. Most of the electronics include passive or active RFID technologies. Passive seals are short range, low cost, and disposable.

They have no inherent electric power such as a battery. The RFID reader or interrogator provides energy when it illuminates or scans the seal.

The passive seal uses the absorbed energy to reflect its information back to the reader. The lack of on-board power limits the functionality.

For example, since passive seals cannot provide continuous power to measure the condition of the seal cable, they cannot detect and record tampering at the time of the event-they simply report whether they are intact or not when interrogated by a reader.

Active seals are more sophisticated, have higher initial costs, and – until prices drop significantly – demand reuse. Active seals carry batteries and the power permits longer range and greater functionality.

To extend the previous example, they can detect tampering when it occurs and add it to a time log of events. If equipped or interfaced with GPS, an active seal can also log the location. Further, some seals can provide live “mayday” tampering reports as the events happen, mostly within specially equipped terminals.

Because of their low unit cost and operational simplicity, passive seals were generally the preferred solution for “pre-September 11” security requirements aimed against theft. The greater functionality of active seals enhances their appeal for “post-September 11” security against terrorist tampering.

NO GLOBAL FREQUENCIES Although several initiatives pursue it, today there are no global frequencies and technical specifications (for power levels and duty cycles) for electronic seals or other RFID logistics applications. Since there appear to be valid requirements for both active and passive technologies, and since active and passive tags cannot operate at the same frequency at the same place and time, global use demands a coordinated set of frequencies.

Reusable seals pose an operational challenge for shippers and carriers. However, if that challenge is mastered, then reusable seals also offer an opportunity to lower the per-use cost of high security seals. Two points may mitigate the operational challenges. First, it appears that a significant portion of commercial containers operate in repetitive service that is more suited to recycling seals. Second, if empty container movements were sealed for security reasons, that should simplify the recycling process.

Electronic seals are relatively new to the market and in limited use. It makes sense to conduct a vigorous pilot and demonstration programme to accelerate the processes of accumulating field experience, fine-tuning products, and developing customer confidence – all important to support regulatory requirements for electronic seals.

Examples of electronic seals given in the report include both active and passive types from Transcore Passive Seal Technology, TydenTek Active Data Seal, Savi EchoPoint SmartSeal and Crown Agents Electronic Seal. Prices vary, according to the sophistication of the product, from US$1.50 to US$250.

The Federal Highway Administration’s full report can be found at www. fhwa. dot. gov