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RFID Technology
RFID Logistics Challenges and Opportunites
By Dr. Qinghan Xiao
Radio frequency identification (RFID) is an automated means of using radio waves to identify and track unique instances of objects or people. As the Electronic Privacy Information Center (EPIC) summarizes, the purpose of an RFID system is to enable data to be transmitted by a portable device (i.e. a tag) that is remotely detected by a reader and processed according to the needs of a particular application.
RFID has been called “the first important technology of the 21st century”1 and has become “one of the most talked-about technologies in business today.”2 RFID technology is not new, however, and was originally developed for improving warfare technologies.
The first application of RFID technology was developed by the British military to differentiate between friendly and hostile aircraft during the Second World War. This ‘Identify Friend or Foe’ (IFF) system marked the origin of active RFID that is used today.
The second era of RFID technology involved commercial activities in the 1960s. One of these early applications was electronic article surveillance (EAS) equipment to counter theft in retail stores. As a forerunner to passive RFID, EAS used a ‘1-bit’ signal to represent the presence or absence of a tag.
The third era of RFID technology began in 1999, when the Auto-ID Centre was established at the Massachusetts Institute of Technology (MIT) to investigate new ways to extend bar code technology.
The 1990s had already proven a significant decade for RFID with the wide-scale deployment of electronic toll collection (ETC) in the U.S. Looking back at the history of the technology, it becomes clear how real-world implementations have been key to pushing it forward.
With the development of RFID standards, decreases in prices and the introduction of broad mandates—from organizations as varied as Wal-Mart and the U.S. Department of Defense (DoD)—for the use of RFID tags by suppliers, the technology is expected to play an important role in a wider range of applications in different domains in the near future.
RFID technology has been implemented in various sectors, including transportation, retail, health care, defence and supply chain management. Among them, logistics is likely the field to which the technology has brought the clearest benefits.
The use of RFID systems within supply chains makes it possible to provide instant inventory management, increase asset visibility, prevent theft, track shipments, recall products and support interoperability in an end-to-end integrated environment.
In supply chains, RFID systems help provide instant inventory management, increase asset visibility, prevent theft, track shipments and support interoperability. Photo courtesy CONOSCOM
Systems
An RFID system usually consists of three major components: the tag, the reader and the back-end system. The system uses antennas and transceivers to transmit and receive RF signals using frequencies in the range of 30 kHz to 2.5 GHz, then transfers the information to the back-end system.
Tags
RFID tags, also known as transponders, are identification devices that can be attached to objects. Each tag typically consists of an antenna constructed of a small coil of wires and a microchip to electronically store information about the object. Unlike bar codes, RFID tags offer the capability to store a unique serial number and product information for each item, not just classes of items.
RFID tags can be categorized as passive, semi-passive or active, in relation to how they are powered, as well as read-only, write-once-read-many (WORM) or read/write, in terms of how their memory works.
Passive tags do not have an internal power source. Instead, they need to draw power from an RFID reader.
The reader emits electromagnetic waves that induce a current in the tag’s antenna, which powers the chip on the tag. When the power to the tag’s chip passes a minimum voltage threshold, the circuit turns on and the tag transmits its information to the reader. Due to the lack of a battery, a passive tag has a relatively short reading range of only a few metres.
A semi-passive RFID tag contains a battery to power its on-board circuitry or sensors to enable the monitoring of environmental conditions, whereas communication is accomplished by drawing power from the reader in a manner similar to that of passive tags.
Due to their use of batteries, semi-passive tags provide faster response times and greater memory capacity compared to passive tags.
An active RFID tag contains its own battery, which is used for both powering the chip and boosting the return signal. This setup enables these tags to continuously monitor high-value goods or a container’s seal status.
Photo courtesy CANOSCOM
Case Study: CANOSCOM
The Canadian Operational Support Command (CANOSCOM) has recently adopted radio-frequency identification (RFID) technology within the Canadian Forces (CF) supply chain to deal with challenges relating to the visibility, tracking and traceability of its logistics assets. CANOSCOM determined the technology would provide a means to significantly improve its supply chain efficiency and responsiveness.
Defence Research and Development Canada (DRDC), an agency of the Department of National Defence (DND), responded to CANOSCOM’s scientific and technological requirements for RFID systems. For example, a study was undertaken to address quantification and qualification of threats to the cargo and distribution system with the implementation of RFID technology.
CF transports many resources—ranging from consumables to tanks—to support its military operations. CANOSCOM’s purpose is to provide effective and efficient support to CF operations both at home and abroad, improving supply chain execution. One of its achievements in this respect has been to adopt RFID technology to track supplies.
DND representatives sought technical and programming assistance with RFID in August 2006 in support of the U.S. Operation Enduring Freedom (OEF) in Afghanistan. Specifically, DND wanted to track Canadian assets at multiple nodes using active RFID tags, write stations, fixed and handheld readers and early-entry deployment support kits.
Shipping hundreds of vehicles and cargo containers between Afghanistan and Canada is costly, so a temporary intermediate staging team (IST) was established, working in close co-ordination with Canada’s North Atlantic Treaty Organization (NATO) allies. The ad hoc IST established by CANOSCOM used RFID technology to manage the rotation of vehicles and equipment in and out of a theatre of operations.
“We have learned through our experiences in Afghanistan the most efficient way of bringing equipment into theatre is to take it by ship to a nearby allied country and cross-load it for the final flight,” said Major-General Daniel Benjamin, CANOSCOM commander.
Sponsored and funded by CANOSCOM, RFID technologies are currently being investigated further by DRDC in Ottawa. This investigation includes testing and evaluating different RFID systems, discovering and analyzing security threats and researching corresponding countermeasures.
To compare the performance among different products, DRDC has tested four types of UHF Generation 2 (Gen 2) Electronic Product Code (EPC) tags for readability, orientation sensitivity and operation, with the tags covered by different materials.
The results for the readability of these passive RFID tags in a parallel orientation (i.e. where each tag faces the reader) were positive, with all four satisfying an approved RF range of 860 to 960 MHz and minimum reading range of 3 m (9.8 ft). These approved ranges ensure compatibility with the logistics specifications of the U.S. Office of the Deputy Under Secretary of Defense.
Compared to passive and semi-passive tags, active tags have wider reading ranges of tens to hundreds of metres, larger memory capacities and faster processing times. However, battery life means the tags can only last up to five years.
As mentioned, depending on the memory type, tags can be further classified as read-only, WORM or read/write.
Read-only tags are typically passive and similar to bar codes because they only carry a serial number. Data stored on the tag cannot be modified or appended unless the microchip is reprogrammed electronically. Read-only tags are available in many versions, varying in range, data bits and operating temperature.
WORM memory allows users to encode tags once during production or distribution. After this initial encoding, the tag’s data becomes locked and cannot be changed.
Read/write tags function like computer disks, because the data stored can be edited, added to or completely rewritten an unlimited number of times. These tags are often implemented on reusable containers and other assets in logistic applications. When the contents of a container are changed, new information can be updated on its tag.
Readers
An RFID reader—sometimes referred to as an interrogator or scanner—is a powered device that communicates with RFID tags and facilitates data transfer between the tags and the back-end system. A typical reader consists of a transmitter, a receiver, an antenna, a microprocessor, memory, a controller and power. The basic functions include activating tags by sending querying signals, supplying power to passive tags, encoding data signals going to the tags and decoding the data received from tags.
Readers can either be wireless, portable handheld units or fixed devices. They can differ considerably in complexity, depending on the type of tags supported and the functions performed, such as sophisticated signal conditioning, parity error checking and correction.
Back-end system and software
A back-end system—essentially an online database—is needed to collect, filter, process and analyze information accurately and efficiently. It stores records of object data, tracking logs and/or other key management information associated with RFID tags.
RFID systems rely on software that can be categorized into three groups: the front-end tag-reading algorithms; middleware; and the back-end system interface.
The front-end algorithms carry out tasks related to signal processing. Middleware, as the name suggests, connects readers to back-end servers and databases; it filters the data acquired by the reader and handles different kinds of user interfaces.
The primary benefits of RFID technology in supply chain management come from its interface with the back-end system. This allows the system to filter information received from the reader, perform matching, tracking and storage functions and then route data to the correct application.
Frequency bands
Systems can also be distinguished by their specific radio frequency (RF). The four primary RF bands—ranging from 30 kHz to 5.8 GHz—include low-frequency (LF), high-frequency (HF), ultra-high-frequency (UHF) and microwave-frequency (MW).
The choice of RF will depend on the application, the size of the tag and the required reading range. In general, the higher the RF, the faster the data transfer or throughput rates, but the more expensive the system.
LF ranges from 30 to 300 KHz. RFID systems in this band commonly operate between 125 and 134 KHz.
In Ottawa, Defence Research and Development Canada (DRDC) has conducted tests to evaluate the readability and orientation sensitivity of different types of RFID tags.
They generally use passive tags with short reading ranges of up to 0.5 m (20 in.) and relatively low overall costs. These systems are most commonly used in security access control, animal identification, asset tracking and vehicle immobilization.
HF ranges from 3 to 30 MHz. HF RFID systems typically operate at 13.56 MHz and use passive tags with reading ranges up to 1 m (3.3 ft) and faster data rates than LF tags. Already, HF systems have been widely used in libraries, mass transit, product authentication and ‘smart identification’ security-related applications, such as electronic passports (e-passports).
UHF ranges from 300 to 1,000 MHz. Passive UHF RFID systems typically operate at 915 MHz in the U.S. and at 868 MHz in Europe, while active UHF RFID systems operate at 315 and 433 MHz, respectively. UHF systems—which are commonly used for logistics applications, including pallet tracking and baggage handling—can send information faster than LF and HF tags and offer the longest reading range of all tags, from 3 to 6 m (9.8 to 19.7 ft) for passive tags and more than 30 m (98 ft) for active tags.
A typical MW RFID system operates at either 2.45 GHz or 5.8 GHz. The lower frequency is traditionally used in long-range access control applications, with a reading range of up to 1 m (3.3 ft) with a passive tag or farther with an active tag. The higher frequency has been allocated in Europe for road traffic and automated toll collection systems.
Challenges
As with wireless hot spots and mobile telephony, RFID is a wireless networking technology for which data security is a critical issue. Like other information systems, it is vulnerable to attack.
Systems can be compromised at various stages. Attacks on an RFID system can generally be categorized into four major groups, based on target:
● Authenticity.
● Integrity.
● Confidentiality.
● Availability.
RFID technology is potentially vulnerable to common attacks, such as eavesdropping, man in the middle attacks (whereby an attacker intercepts and retransmits data) and denial of service (DoS) attacks. It is also, in particular, susceptible to reverse engineering, spoofing and power attacks (see Figure 2).
Reverse engineering is basically the process of taking something apart to figure out how it works. It may be possible for an attacker to extract an RFID tag’s chip and optically read the content of its memory. The ability to then reverse engineer a tag raises privacy concerns, especially when the tag contains personal or biometric information.
Eavesdropping involves an attacker intercepting the data communication between tag and reader, using a compliant reader. Since most RFID systems use clear-text communication, due to limiting tag memory capacity to lower costs, eavesdropping is a simple but efficient means for the attacker to obtain tag data.
DoS attacks can take different forms, including attacks on tags, the network or the back-end system. The purpose of these attacks is not to steal or modify information, but to disable the RFID system so that it cannot be used.
Tag cloning is a type of spoofing attack whereby an attacker captures data from a legitimate RFID tag, then creates an unauthorized copy of the captured sample with a blank tag. In January 2005, for example, researchers from Johns Hopkins University and RSA Labs published the results of cloning a cryptographically protected Texas Instruments digital signature transponder (DST) that was used to buy gasoline and activate a car’s ignition.
While RFID has been successfully implemented in many areas, it is still an emerging technology. As it evolves and its challenges are met, it will bring further change to both the public and private sectors.
Dr. Qinghan Xiao at Defence Research and Development Canada (DRDC) in Ottawa is manager of the RFID Security Project sponsored and funded by the Canadian Operational Support Command (CANOSCOM). For more information, visit www.drdc-rddc.gc.ca.
References
1Simson Garfinkel and Beth Rosenberg, RFID: Applications, Security, and Privacy, Addison-Wesley Professional (July 6, 2005).
2Charles C. Poirier and Duncan Mccollum, RFID Strategic Implementation and ROI: A Practical Roadmap to Success, J. Ross Publishing (March 8, 2006).
This article originally appeared in the September/October 2008 edition of Government Purchasing Guide www.gpgmag.ca
