The thinking behind fingerprint ID is straightforward but the means of implementing it is more complex. The system relies on the unique identifiable imprint left by human touch which is unmatched by machine-to-machine interfaces.

"Computer-generated codes – no matter how elaborately designed – can be replicated. A fingerprint, however, is a unique signature that is only replicated when the person touches something," says Patrick Banas, Siemens Automotive’s director of Body Electronics, North America.

The potential for the technology is enormous as it combines ease and convenience with high levels of security. It will no longer be possible to attempt to guess or crack passwords but the process of logging on for a legitimate user can become much quicker.

Siemens have applied this thinking to a number of products including computers, cars and mobile phones. A mobile phone containing operator identification hardware contains a fingertip sensor, memory and a processor with computing power capable of running fingerprint recognition algorithms. "As many as 60 fingerprints can be stored by the new unit and private telephone books can be individually assigned to various callers as can the call units used," says Banas.

Applying maths to biology in this way is known as "Biometric Technology". Siemens believe the obvious next step for this technology is within the automotive industry. Siemens Automotive engineers expect fingerprint recognition for engine ignition to reach the production-ready stage within two years.

"With the touch of a person’s live fingertip to a center console mounted switch, a high-performance computer identification system authorises and completes the engine ignition sequence in a matter of milliseconds. The process is much faster than pushing a key in the ignition lock, then turning that key to start the engine," says Banas.

The engine start identification process utilises 65,000 electrodes to measure within one hundredth of a millimetre the distance between the sensor and the skin surface; by lightly touching the capacitive sensor, a digitised fingerprint image is created. Image processing software then searches and stores as many as 24 specific fingerprint characteristics. The system-stored fingerprint and the live fingerprint touching the sensor are algorithm-compared by a digital signal processor. Only when both fingerprints match does a silicon chip release a signal to activate authorisation and engine start functions. About the size of a penny, the 160 square millimetre silicon chip contains a sensing field, analogue-digital converter, sequencing control, clock generator and parallel interface.

By combining the unique identifying process of fingerprint ID with an onboard computer, Siemens believe it would be easy to activate personal settings for the vehicle. The system would simply determine who you were and adjust seating, mirror positions, climate, stereo and other devices to the user's personal preferences.

Fingertip sensors – produced from the same Complimentary Metal Oxide Semiconductor (CMOS) technology used for conventional memory chips – is just one of many technologies Siemens are currently developing. They stress that their high level of investment in research and development is key to their ability to bring such technologies to production.