In recent years automatic identification procedures (Auto-ID) have become very popular in many service industries, purchasing and distribution logistics, industry, manufacturing companies and material flow systems. Automatic identification procedures exist to provide information about people, animals, goods and products in transit.

The omnipresent barcode labels that triggered a revolution in identification systems some considerable time ago, are being found to be inadequate in an increasing number of cases. Barcodes may be extremely cheap, but their stumbling block is their low storage capacity and the fact that they cannot be reprogrammed.

The technically optimal solution would be the storage of data in a silicon chip. The most common form of electronic data-carrying devices in use in everyday life is the smart card based upon a contact field (telephone smart card, bank cards). However, the mechanical contact used in the smart card is often impractical. A contactless transfer of data between the data-carrying device and its reader is far more flexible. In the ideal case, the power required to operate the electronic data-carrying device would also be transferred from the reader using contactless technology. Because of the procedures used for the transfer of power and data, contactless ID systems are called RFID systems (radio frequency identification).

The number of companies actively involved in the development and sale of RFID systems indicates that this is a market that should be taken seriously. Whereas global sales of RFID systems were approximately 900 million $US in the year 2000 it is estimated that this figure will reach 2650 million $US in 2005 (Krebs, n.d.). The RFID market therefore belongs to the fastest growing sector of the radio technology industry, including mobile phones and cordless telephones.

Furthermore, in recent years contactless identification has been developing into an independent interdisciplinary field, which no longer fits into any of the conventional pigeonholes. It brings together elements from extremely varied fields: RF technology and EMC, semiconductor technology, data protection and cryptography, telecommunications, manufacturing technology and many related areas.

As an introduction, the following section gives a brief overview of different automatic ID systems that perform similar functions to RFID.

Automatic Identification Systems
Barcode Systems
Barcodes have successfully held their own against other identification systems over the past 20 years. According to experts, the turnover volume for barcode systems totalled around 3 billion DM in Western Europe at the beginning of the 1990s (Virnich and Posten, 1992).

 

The barcode is a binary code comprising a field of bars and gaps arranged in a parallel configuration. They are arranged according to a predetermined pattern and represent data elements that refer to an associated symbol. The sequence, made up of wide and narrow bars and gaps, can be interpreted numerically and alphanumerically. It is read by optical laser scanning, i.e. by the different reflection of a laser beam from the black bars and white gaps (ident, 1996). However, despite being identical in their physical design, there are considerable differences between the code layouts in the approximately ten different barcode types currently in use.

The most popular barcode by some margin is the EAN code (European Article Number), which was designed specifically to fulfil the requirements of the grocery industry in 1976. The EAN code represents a development of the UPC (Universal Product Code) from the USA, which was introduced in the USA as early as 1973. Today, the UPC represents a subset of the EAN code, and is therefore compatible with it (Virnich and Posten, 1992).

The EAN code is made up of 13 digits: the country identifier, the company identifier, the manufacturer’s item number and a check digit.

In addition to the EAN code, the barcodes shown in Table 1.1 are popular in other industrial fields.

Optical Character Recognition
Optical character recognition (OCR) was first used in the 1960s. Special fonts were developed for this application that stylised characters so that they could be read both in the normal way by people and automatically by machines. The most important advantage of OCR systems is the high density of information and the possibility of reading data visually in an emergency, or simply for checking (Virnich and Posten, 1992). Today, OCR is used in production, service and administrative fields, and also in banks for the registration of cheques (personal data, such as name and account number, is printed on the bottom line of a cheque in OCR type). However, OCR systems have failed to become universally applicable because of their high price and the complicated readers that they require in comparison with other ID procedures.

Biometric Procedures
Biometrics is defined as the science of counting and (body) measurement procedures involving living beings. In the context of identification systems, biometry is the general term for all procedures that identify people by comparing unmistakable and individual physical characteristics. In practice, these are fingerprinting and handprinting procedures, voice identification and, less commonly, retina (or iris) identification.

Voice Identification
Recently, specialised systems have become available to identify individuals using speaker verification (speaker recognition). In such systems, the user talks into a microphone linked to a computer. This equipment converts the spoken words into digital signals, which are evaluated by the identification software.

The objective of speaker verification is to check the supposed identity of the person based upon their voice. This is achieved by checking the speech characteristics of the speaker against an existing reference pattern. If they correspond, then a reaction can be initiated (e.g. ‘open door’).

Fingerprinting Procedures (Dactyloscopy)
Criminology has been using fingerprinting procedures for the identification of criminals since the early twentieth century. This process is based upon the comparison of papillae and dermal ridges of the fingertips, which can be obtained not only from the finger itself, but also from objects that the individual in question has touched.

When fingerprinting procedures are used for personal identification, usually for entrance procedures, the fingertip is placed upon a special reader. The system calculates a data record from the pattern it has read and compares this with a stored reference pattern. Modern fingerprint ID systems require less than half a second to recognise and check a fingerprint. In order to prevent violent frauds, fingerprint ID systems have even been developed that can detect whether the finger placed on the reader is that of a living person (Schmidh¨ausler, 1995).

Smart Cards
A smart card is an electronic data storage system, possibly with additional computing capacity (microprocessor card), which – for convenience – is incorporated into a plastic card the size of a credit card. The first smart cards in the form of prepaid telephone smart cards were launched in 1984. Smart cards are placed in a reader, which makes a galvanic connection to the contact surfaces of the smart card using contact springs. The smart card is supplied with energy and a clock pulse from the reader via the contact surfaces. Data transfer between the reader and the card takes place using a bidirectional serial interface (I/O port). It is possible to differentiate between two basic types of smart card based upon their internal functionality: the memory card and the microprocessor card.

One of the primary advantages of the smart card is the fact that the data stored on it can be protected against undesired (read) access and manipulation. Smart cards make all services that relate to information or financial transactions simpler, safer and cheaper. For this reason, 200 million smart cards were issued worldwide in 1992. In 1995 this figure had risen to 600 million, of which 500 million were memory cards and 100 million were microprocessor cards. The smart card market therefore represents one of the fastest growing subsectors of the microelectronics industry.

One disadvantage of contact-based smart cards is the vulnerability of the contacts to wear, corrosion and dirt. Readers that are used frequently are expensive to maintain due to their tendency to malfunction. In addition, readers that are accessible to the public (telephone boxes) cannot be protected against vandalism.

Memory Cards
In memory cards the memory – usually an EEPROM – is accessed using a sequential logic (state machine) (Figure 1.5). It is also possible to incorporate simple security algorithms, e.g. stream ciphering, using this system. The functionality of the memory card in question is usually optimised for a specific application. Flexibility of application is highly limited but, on the positive side, memory cards are very cost effective. For this reason, memory cards are predominantly used in price-sensitive, large-scale applications (Rankl and Effing, 1996). One example of this is the national insurance card used by the state pension system in Germany (Lemme, 1993).

Microprocessor Cards
As the name suggests, microprocessor cards contain a microprocessor, which is connected to a segmented memory (ROM, RAM and EEPROM segments).

The mask programmed ROM incorporates an operating system (higher program code) for the microprocessor and is inserted during chip manufacture. The contents of the ROM are determined during manufacturing, are identical for all microchips from the same production batch, and cannot be overwritten.

The chip’s EEPROM contains application data and application-related program code. Reading from or writing to this memory area is controlled by the operating system.

The RAM is the microprocessor’s temporary working memory. Data stored in the RAM are lost when the supply voltage is disconnected.

Microprocessor cards are very flexible. In modern smart card systems it is also possible to integrate different applications in a single card (multi-application). The application-specific parts of the program are not loaded into the EEPROM until after manufacture and can be initiated via the operating system.

Microprocessor cards are primarily used in security-sensitive applications. Examples are smart cards for GSM mobile phones and the new EC (electronic cash) cards. The option of programming the microprocessor cards also facilitates rapid adaptation to new applications.

Country identifier Company identifier Manufacturer’s item number CD
4 0 1 2 3 4 5 0 8 1 5 0 9
FRG Company Name 1 Road Name 80001 Munich Chocolate Rabbit 100 g

Figure 1.3 Example of the structure of a barcode in EAN coding