RFID
Introduction
RF-ID: Radio Frequency Identification
RF-ID solutions are generally perceived as the future of automated supply chain information technology, though they were already in use in the nineties. Essentially, an RF-ID system comprises of two main components: The transponder (RF-ID tag) is capable of storing information and is attached to the object that is supposed to be identified. An RF-ID reader on the other hand is designed to read and, depending on the technology used, write the information in the tag remotely by radio transmission. RF-ID tags (or Smart Labels) are the technological successor of the well-known bar codes and will gradually replace those.
In contrast to bar code stickers which are read optically, RF-ID tags do not have to be placed in front of a reader one by one sequentially but may instead be processed almost simultaneously within a certain range, thanks to an anti-collision mechanism. The maximum distances between tags and reader ranges from a few inches to several feet depending on equipment used. The information stored on the tags also varies greatly and may range from a single-bit signal (anti-theft device) to a product identification code to even larger data structures. There are different tag types for different purposes. Depending on the application at hand one may choose between read-only and read/write tags. Depending on the tag type the cost per tag can be surprisingly low.
The challenge in implementing am RF-ID system is the design of working tag concept with careful security considerations. Typical business cases for RF-ID solutions are supply chain and logistics.
RF-ID Modeling
Depending on the application suitable tag types should be chosen to precisely solve the task defined in an earlier design phase. With a large variety of tag types and tag manufactures it is essential to understand the criteria to distinguish and assess the available solutions.
1. Power supply
- Passive transponders do not have their own power supply and need to draw their energy from the electromagnetic field of the tag reader.
- Active transponders come with their own battery to power the chip as well as data transmission.
2. Operation mode
- Full- and half-duplex: The transponder sends its information when the HF field is powered by the reader. Specific strategies are required to handle weak transpinder signals and distinguish them from the reader’s own signal.
- Sequential transmission: The transponder submits its data during periodic power-down phases of the reader. In this operation mode power supply can be an issue and additional batteries or capacitors are required.
3. Data load
- A 1-bit-transponder is only capable of submitting to different states. This is sufficient for certain security tasks (surveillance) and advantageous because of relatively low costs.
- Other transponders are capable of storing several kilobytes of data.
4. Customizations
- Read-only tags are usually assigned a unique ID number by the tag manufacturer.
- Read/write tags may be over-written by the reader. These tag types are more expensive and require a reliable security concept.
5. Frequency
- Low frequency: 125KHz
Common frequency for low-cost passive transponder solutions.
- High frequency: 13,56MHz
Manly used for product labels.
- High frequency: 860-956MHz
For labels with read/write access up to a range of about 10 feet.
- Ultra high frequency: 2,4GHz
For tags with greater range.
6. Range
- Primarily, range is dependent on the application and tag frequency. 100-135kHz: 200cm, 13,56 MHz: up to 100cm, 868 (915) MHz passive: 2m, 868 (915) MHz active: 6-8m, 2,45 GHz: up to 12m
7. Costs
- Tag prices vary from cents for low-frequency passive tags to $100 for active high-frequency tags.
8. Physical design
Tags come in different forms and shapes. Among them are the frequently used coin-shape or plastic/glass chassis in different variations. Tags may be integrated directly into watches or key chains. Smart Labels are flexible enough to be integrated into credit-card size stickers. These can then be attached directly to individual products, palettes or containers.
Applications
RF-ID solutions can be used in many different areas, most prominently identification and accounting systems.
- Containers / product identification:
Tags can be attached to store general information about an item. Origin, destination and content can therefore be processed automatically.
- Retail:
Products in a store can be equipped with price tags. The customer simply carries the items through a sensor. The system recognizes the price and charges against a customer account or demands payment. Finally the tags are removed or deactivated.
- Anti-theft devices for cars:
The transponder is attached to the key and initialized with a special identification code. The owner of the vehicle has to be inside the car with his key to deactivate the protective device.
- Ticketing / access control:
Often consumers require access to designated areas. A chip card contains the identification technology and opens a door for example as soon as the card is in close proximity to the reader. Therefore ID cards do not need to be checked manually. Advantages are low costs and speed (think of an event in a sports stadium with 30,000 visitors).
- Automation:
When attaching transponders to objects on an assembly line there are advantages in supervising and adjusting production processes. By placing readers at key points in the assembly process, production flow and status may be monitored centrally.
- Decentralized control:
In addition it is possible to store additional information on the tag, e.g. color or other optional choices before production begins. This way it is possible to paint the object with the correct color during the production process without accessing a central database through a network.
Security concerns
A lack of security allows an attacker with a read/write device to launch several different attacks:
- Forge contents:
Writable un-protected tags can easily be modified. An attacker might change the price of a product.
- Forge identity:
By reading a tag an attacker might gain knowledge of important ID and security information. Using a duplicate transponder or a device simulating a transponder a reader can be tricked to grant access to a restricted area.
- Physical manipulation:
Transponder can be removed from one item and attached to another one. This way properties of the old object can be transferred to the new one, e.g. price.
- Eavesdropping:
By tapping into the radio transmissions confidential information can be exposed.
- Deactivation / destruction:
Signal strength can be influenced and weakened so that reliable transmissions become impossible. The transponder cannot be read and the system might end up in an undefined state. This situation could be exploited for further attacks.
More information can be found in a study by the BSI (Bundesamtes für Sicherheit in der Informationstechnik):
http://www.bsi.bund.de/fachthem/rfid/studie.htm
References
http://www.art-events.de/systeme/0404xx-rf-id.htm
http://www.rfdump.org
http://en.wikipedia.org/wiki/RFID
http://www.lfd.niedersachsen.de/master/C3346118_N3349657_L20_D0_I560.html
RF-ID: Radio Frequency Identification
RF-ID solutions are generally perceived as the future of automated supply chain information technology, though they were already in use in the nineties. Essentially, an RF-ID system comprises of two main components: The transponder (RF-ID tag) is capable of storing information and is attached to the object that is supposed to be identified. An RF-ID reader on the other hand is designed to read and, depending on the technology used, write the information in the tag remotely by radio transmission. RF-ID tags (or Smart Labels) are the technological successor of the well-known bar codes and will gradually replace those.
In contrast to bar code stickers which are read optically, RF-ID tags do not have to be placed in front of a reader one by one sequentially but may instead be processed almost simultaneously within a certain range, thanks to an anti-collision mechanism. The maximum distances between tags and reader ranges from a few inches to several feet depending on equipment used. The information stored on the tags also varies greatly and may range from a single-bit signal (anti-theft device) to a product identification code to even larger data structures. There are different tag types for different purposes. Depending on the application at hand one may choose between read-only and read/write tags. Depending on the tag type the cost per tag can be surprisingly low.
The challenge in implementing am RF-ID system is the design of working tag concept with careful security considerations. Typical business cases for RF-ID solutions are supply chain and logistics.
RF-ID Modeling
Depending on the application suitable tag types should be chosen to precisely solve the task defined in an earlier design phase. With a large variety of tag types and tag manufactures it is essential to understand the criteria to distinguish and assess the available solutions.
1. Power supply
- Passive transponders do not have their own power supply and need to draw their energy from the electromagnetic field of the tag reader.
- Active transponders come with their own battery to power the chip as well as data transmission.
2. Operation mode
- Full- and half-duplex: The transponder sends its information when the HF field is powered by the reader. Specific strategies are required to handle weak transpinder signals and distinguish them from the reader’s own signal.
- Sequential transmission: The transponder submits its data during periodic power-down phases of the reader. In this operation mode power supply can be an issue and additional batteries or capacitors are required.
3. Data load
- A 1-bit-transponder is only capable of submitting to different states. This is sufficient for certain security tasks (surveillance) and advantageous because of relatively low costs.
- Other transponders are capable of storing several kilobytes of data.
4. Customizations
- Read-only tags are usually assigned a unique ID number by the tag manufacturer.
- Read/write tags may be over-written by the reader. These tag types are more expensive and require a reliable security concept.
5. Frequency
- Low frequency: 125KHz
Common frequency for low-cost passive transponder solutions.
- High frequency: 13,56MHz
Manly used for product labels.
- High frequency: 860-956MHz
For labels with read/write access up to a range of about 10 feet.
- Ultra high frequency: 2,4GHz
For tags with greater range.
6. Range
- Primarily, range is dependent on the application and tag frequency. 100-135kHz: 200cm, 13,56 MHz: up to 100cm, 868 (915) MHz passive: 2m, 868 (915) MHz active: 6-8m, 2,45 GHz: up to 12m
7. Costs
- Tag prices vary from cents for low-frequency passive tags to $100 for active high-frequency tags.
8. Physical design
Tags come in different forms and shapes. Among them are the frequently used coin-shape or plastic/glass chassis in different variations. Tags may be integrated directly into watches or key chains. Smart Labels are flexible enough to be integrated into credit-card size stickers. These can then be attached directly to individual products, palettes or containers.
Applications
RF-ID solutions can be used in many different areas, most prominently identification and accounting systems.
- Containers / product identification:
Tags can be attached to store general information about an item. Origin, destination and content can therefore be processed automatically.
- Retail:
Products in a store can be equipped with price tags. The customer simply carries the items through a sensor. The system recognizes the price and charges against a customer account or demands payment. Finally the tags are removed or deactivated.
- Anti-theft devices for cars:
The transponder is attached to the key and initialized with a special identification code. The owner of the vehicle has to be inside the car with his key to deactivate the protective device.
- Ticketing / access control:
Often consumers require access to designated areas. A chip card contains the identification technology and opens a door for example as soon as the card is in close proximity to the reader. Therefore ID cards do not need to be checked manually. Advantages are low costs and speed (think of an event in a sports stadium with 30,000 visitors).
- Automation:
When attaching transponders to objects on an assembly line there are advantages in supervising and adjusting production processes. By placing readers at key points in the assembly process, production flow and status may be monitored centrally.
- Decentralized control:
In addition it is possible to store additional information on the tag, e.g. color or other optional choices before production begins. This way it is possible to paint the object with the correct color during the production process without accessing a central database through a network.
Security concerns
A lack of security allows an attacker with a read/write device to launch several different attacks:
- Forge contents:
Writable un-protected tags can easily be modified. An attacker might change the price of a product.
- Forge identity:
By reading a tag an attacker might gain knowledge of important ID and security information. Using a duplicate transponder or a device simulating a transponder a reader can be tricked to grant access to a restricted area.
- Physical manipulation:
Transponder can be removed from one item and attached to another one. This way properties of the old object can be transferred to the new one, e.g. price.
- Eavesdropping:
By tapping into the radio transmissions confidential information can be exposed.
- Deactivation / destruction:
Signal strength can be influenced and weakened so that reliable transmissions become impossible. The transponder cannot be read and the system might end up in an undefined state. This situation could be exploited for further attacks.
More information can be found in a study by the BSI (Bundesamtes für Sicherheit in der Informationstechnik):
http://www.bsi.bund.de/fachthem/rfid/studie.htm
References
http://www.art-events.de/systeme/0404xx-rf-id.htm
http://www.rfdump.org
http://en.wikipedia.org/wiki/RFID
http://www.lfd.niedersachsen.de/master/C3346118_N3349657_L20_D0_I560.html
Last modified 2005-09-01 06:30 PM
DN-Systems at LinuxTag 2007
