The Technology behind High-Speed Processing

A key advantage of FeliCa is its significantly faster authentication speed comparred to other IC card systems. This advantage is especially important in Japan, where transportation systems must cope with high passenger volumes. The high-speed processing capacity of the FeliCa system is based on two key technologies. One is an encoding system that can cope with distance-related fluctuations. The other is a unique mutual authentication method.

The FeliCa card sends and receives encoded data produced by the card and the reader/writer. Unlike conventional serial communication, the FeliCa system operates without direct contact. Sony adopted technology to support communication in this special environment. The FeliCa system uses a highly efficient packet communication method. Command data produced by the FeliCa OS and response data to inquiries from the reader/writer are authenticated and recorded between the card and reader/writer. These tasks are carried out using Manchester encoding, which is highly tolerant of distance-related fluctuations.

Manchester Encoding

The card and the reader/writer communicate digitally using 0s and 1s. In the Manchester encoding system, 0s and 1s are transmitted as transitions between high and low signals. A 0 is sent as a waveform that rises from a low level in the middle of the bit period, while for a 1 the waveform starts at a high level and falls. Because there is no direct current component in one -bit duration, it is easy to establish a threshold when the signals are turned back into data. This characteristic allows ensures effective transmission even when there is a big jump in a signal level caused by tapping the FeliCa card on the reader writer.

Figure 3 Another encoding method used with contactless IC cards is the non-return to zero (NRZ) system. With this method, a 0 is represented as a low level and a 1 as a high level. A weakness of this method is the tendency of the average value to deviate when certain types of data (such as a continuous stream of the same bits) are transmitted. If distance causes fluctuation, it can become difficult to distinguish between 0s and 1s. With Manchester encoding, it is easy to determine the signal cycle, since signals are transmitted fluidly. Manchester encoding is also noise-tolerant.

Unique Mutual Authentication System-Simultaneous Authentication of Multiple Cards

Figure 4: Multi-Application

The FeliCa system employs a unique mutual authentication method between the card and the reader/writer during transaction processing, which involves the processing of multiple tasks in a secure environment. Normally, when authentication is carried out for multiple processes, it is necessary to access and authenticate each function requiring authentication. Because the time required increases with the number of functions, the efficiency of payment and authentication services is reduced.
With the FeliCa system it is not necessary to authenticate individual functions separately and instead generates a composite key is generated. This is a combined key made from multiple access keys. This allows mutual authentication of multiple functions simultaneously. Up to 16 services can be supported at the same time using this abbreviated key. For example, personal authentication, payment, balance, points and other functions can all be carried out instantaneously.

Excellent Security

The FeliCa card was the first IC card in the world to be certified under ISO/IEC 15408 EAL4, which is an extremely rigorous international standard for security evaluation. Before FeliCa, it was believed that no contactless IC card would be able to meet this standard including the hardware and operating system. The FeliCa card's security technology is based on mutual authentication between the card and the reader/writer, and on the encryption of transmitted data. Encryption is carried out using an open-standard security algorithm. The encryption key for transmitted data is generated dynamically for each transaction, and random numbers are used during mutual authentication. These measures guard against impersonation and other fraudulent actions.

The Future of the Technology

Sony perfected the FeliCa system by bringing together its accumulated knowledge in various fields of technology, including semiconductor design and fabrication, communications and security. The result is a system that combines robust security with high-speed authentication and the versatility to support applications on a wide range of equipment, including mobile phone "wallets" and PCs. FeliCa technology is already used in Japan and Asia, and there are plans for its adoption in North America and Europe.

By adding Near Field Communication (NFC) capabilities incorporating FeliCa communication technology to consumer electronic equipment, it will be possible to transmit data and make payments using contactless IC cards simply and intuitively. Simple touch controls will provide easy access to an even wider variety of content.