The present invention relates to an identification card and a method of identifying a card holder using the card and in particular to an identification card using biometric characteristics for identification. The term card holder refers to a person who holds the card between their index finger and thumb under normal operating conditions. However, it will of course be appreciated that a physically compromised person may hold the card between any of their adjacent body parts, such as fingers, toes allowing operation of the invention.

Biometrics is well researched, and there seems to be virtually no limit to the body parts, personal characteristics and reading methods used for biometric identification: fingers, hands, feet, faces, eyes, ears, teeth, veins, voices, signatures, typing styles, Human DNA, gaits and odours. Biometrics tackles the weakest links in our systems, and works on improving the security of those elements to mitigate risk against security attacks, of which on average eighty percent are password-related.

A snapshot of where biometric applications are being used shows that physical access control i. e. protecting buildings and rooms from unauthorized entry is credited with roughly half of all sales of biometric devices in the year 2001. Logical access control i. e. protecting computers and networks represented forty percent of the market and time and attendance applications accounted for the remainder. There are many biometric technologies that are readily available for exploitation. The existing key biometric applications currently developed and available are summarised as follows : Hand Geometry-The hand is very robust and would require considerable physical damage to significantly alter the geometry. The hand is not very distinctive, with many people sharing common geometrical representation. The hand is accessible as it is easy to present The hand is acceptable as opinion is that it does not invade personal privacy.

The hand availability is low as typically only one hand geometry can be presented, as the left hand is often a near mirror image of the right.

Fingerprints-The fingerprint is not very robust and is susceptible to chemical and physical damage. The fingerprint is very distinctive with primary applications based on criminal identification within the Law Enforcement agencies. The fingerprint is accessible but often requires real-time feedback to the user regarding proper presentation and can be complicated by skin ailments. The fingerprint is acceptable as opinion is that it does not invade personal privacy. The fingerprint availability is high as typically a person can present at least six nearly independent fingerprints. The palm can also be included within this category but is rarely used.

State-of-the-art in this area is the result of an EU funded Cost-Sharing project (IST-2000-25168) which ended in June 2002, co-ordinated by lnfineon Technologies AG (DE), entitled"Biometric Matching and Authentication System on Card (Finger Card)".

Face-The face is robust being an area of the body that is well protected. The face is not very distinctive with primary applications based on criminal identification matching to known suspects. The face is accessible as systems can capture images from distance (several meters) using video equipment but orientation problems distort the data collection. The face is acceptable as opinion is that it does not invade personal privacy.

The face availability is high as typically a person can present several independent features but orientation may distort these. There is also the technical infrastructural cost associated with acquiring the source data from the face and other parts of the human body not to mention the need for the human to participate in the acquisition of such data by standing in the correct position or interacting with certain devices to source the data.

Eyes-The eye is very robust being an area of the body that is well protected. The eye is very distinctive with primary applications based on retinal scanning although iris scanning is also developed. The eye is accessible but can be complicated although retinal scanning reduces the orientation problems because the eye naturally aligns itself as it focuses on an illuminated target. Iris scanning does not require the person to interact

with a device but instead uses a video image of the eye which can be taken from one foot away. The eye is acceptable as opinion is that it does not invade personal privacy. The eye availability is complicated by the fact that multiple areas of the retina can be presented by moving the eye in various directions.

Voice-The voice is robust but there are a whole range of things that impact voice verification such as colds and flu, medication and stress. The voice is very distinctive demonstrating a 0.3% false acceptance rate (FAR). The voice is accessible but does vary due to the positional changes of the body, the physical well-being of the speaker and time.

The voice is acceptable and is clearly non-invasive but may not always be appropriate for some personal transactions or social environments. The voice availability is high as it is determined by many different factors: size of the vocal cavities (throat, oral, nasal) as well as the characteristics of the vocal chords themselves and is further modified by the way you speak-the way your mouth, lips, tongue, jaw and teeth move.

Skin Chemistry-The skin chemistry is not well documented with main references to fingerprinting and the authentication of a'real'finger. The main application being researched is through the IBM patent (referenced below) which is developing DNA sampling which is known to be robust, distinctive, accessible and available.

In the area of development of a biometric sensor on-card, US Patent No.

2002095587 in the name of IBM, entitled"Smart card with integrated biometric sensor" focuses on the sampling of a fingerprint, a palm print, a voice print, a retina and/or skin chemistry.

US Patent No. 6347040 in the name of Infineon Technologies AG (DE), entitled "Sensor device for sensing biometric characteristics, in particular finger minutiae" discloses a sensor device with a biometric sensor chip. The sensor chip is fastened on a flexibie printed circuit board that has a highiy flexible substrate layer and conductor tracks applied to the substrate layer. The conductor tracks are in electrical contact with the sensor chip and are led to a terminal region of the flexible printed circuit board. The

sensing area of the sensor chip is accessible through an opening in the flexible circuit board and the opening is at least partially surrounded by a grounding frame.

German Patent No. DE10126839 filed by Infineon Technologies AG (DE), entitled "Fingerprint sensor for personal identification incorporates electrostatic discharge protection and verification that applied finger is living tissue"focuses on the sampling of a finger to identify the presence of living tissue by diversion of a received electrostatic charge that is used for impedance measurement in association with a measuring circuit.

The surface resistance is determined mainly by conductivity of a liquid (sweat) covering the skin and this technology attempts to tackle the issue of fake generated prints.

The main problem associated with the implementation of newly developed biometric'smart cards'is a financial obstacle because of the requirement to install software and hardware at each reading facility. This provides no problem where newly developed card readers are being installed for the first time but for old ATM machines for example, the financial cost of installing hardware and software at all ATM's is prohibitive in the extreme. This problem arises in the first place because traditional biometric measurement can not be economically miniaturised sufficiently to fit on-card meaning additional external readers are required forcing the market to standardise on one biometric.

Clearly, there is a need for a new method of human identification using an identification card which is interoperable with existing systems thereby overcoming the infrastructural problem. Such a system should not require additional training on behalf of the user and should essentially provide a method of uniquely identifying the human.

Accordingly, the present invention provides an identification card having means for generating and transmitting signals into the body of a card holder and means for receiving and interpreting the signals from the card holder's body, the signals being attenuated by bioelectrical impedance of the card holder's body such that the interpretation of the attenuated signals by the interpretation means provides a bioelectrical impedance signature for uniquely identifying the card holder.

Bioelectrical impedance is measurable with simple technical instruments which facilitates the ability to miniaturise the biometric sensing technology to a degree suitable for on-card implementation.

Ideally, the means for generating and transmitting signals into the body of a card holder and the means for receiving and interpreting the signals from the card holder's <BR> <BR> body comprises a controller having a central processing unit (C. P. U. ) and an associated memory, two or more electrodes disposed on an external surface of the identification card and electronic control circuitry electrically coupling the electrodes to the controller.

Preferably, the two or more electrodes are provided on opposing main faces of the identification card.

Ideally, the two or more electrodes are located so that the forefinger and the thumb are naturally located thereon when the card is held between the forefinger and the thumb.

Preferably, the electronic control circuitry comprises means for generating a range of analogue signals of varying currents and frequency.

Ideally, the currents are in the range of 100pA to 900pA.

Preferably, the frequency of the signals is in the range of 1 KHZ to 1350 KHZ.

Ideally, the electronic control circuitry has means for filtering the attenuated signals, converting the analogue signals to digital signals and passing the signals to the C. P. U. for interpretation.

Preferably, the means for generating and interpreting signals comprises a software control module stored on the memory of the controller.

Ideally, the software control module compares a live bioelectrical impedance signature with a bioelectrical impedance signature recorded in the memory of the controller. Live biometric data describes information obtained by the card from the person currently holding the card as opposed to information from the person whose biometric data was originally recorded by the card issuing authority. Such comparison is performed under the control of a neural network module that will observe, team and verify the thresholds of the biometric data within acceptable tolerance limits.

Preferably, the software control module has means for identifying bioelectrical impedance characteristics representative of fat mass, body cell mass, extra cellular water and skeletal mass.

Ideally, the software control module is capable of generating, transmitting, receiving and interpreting signals in a time interval in the range of a few seconds to provide a card holder identified or card holder not identified output to allow or prohibit a transaction to proceed respectively.

Ideally, the time interval is approximately one second.

Preferably, the software control module has means for generating a unique bioelectrical impedance signature for a specific card holder from a full set of data including thumb-forefinger only loop, skin resistivity, sweat, geographical regionality, weight, age, gender, current, voltage measurement and frequency range.

Ideally, the identification card has means for transmitting live biometric data to an authorisation unit via freespace communications protocols.

Preferably, the identification card has means for transmitting an authorisation signal generated in response to successful identification of a cardholder to an authorisation unit via freespace communications protocols.

Ideally, an authorised card user's bioelectrical impedance signature is stored on the identification card in a read only memory (ROM).

Preferably, means for encrypting bioelectrical impedance signatures is stored on the memory of the controller.

Ideally, the identification card has an embedded radiation emitter for allowing the spatial location of the identification card to be defined at any given time.

Preferably, the controller is powered by a card reader power source. Advantageously, this removes the need for a power source on the aiready busy identification card. This type of card is suitable for use with ATMs (Automatic Teller Machines), swipe-card readers and similar card reading devices.

Ideally, the software control module executes in response to the identification card being at least partially inserted into a card reader.

In an alternative embodiment, the identification card has its own on board power source capable of providing sufficient power for independent operation of the identification card. This embodiment of card is suitable for use when the card is to be used for identification purposes without interaction with an ATM, swipe-card reader or similar reading device.

Ideally, the software control module executes in response to the electrodes of the identification card being held between a card holder's finger and thumb for a predetermined period of time.

Preferably, a card holder's bioelectrical impedance signature is stored on the card in a read only memory, this signature being recorded during initial cardholder enrolment and primary data calibration in a secure environment.

Advantageously, the card does not require the information to be disclosed to or verified by any external comparative databases or reading applications, protecting the citizen's rights and removing the interoperability and infrastructural data protection issues.

Advantageously, the card reader does not require any additional sensing equipment.

Ideally, the software control module has error identifying means for identifying minor differences in biometric, sensor, presentation or transmission information which occur even though the person enrolled and the person currently operating the card are the same.

Advantageously, these error identifying means allow a transaction to proceed in event of minor differences.

Ideally, the error identifying means comprises robustly designed algorithms taking into account thumb-forefinger only loop, skin resistivity, sweat, geographical regionality, weight, age, gender, current, voltage measurement and frequency range.

Preferably, the card has means for indicating when a cardholder has been positively identified and when a cardholder has not been identified.

Ideally, the indicating means comprises a green and red L. E. D although the method of conveying the result of the verification phase can vary to accommodate the architecture and GUI on the card reader.

Advantageously, this alerts the cardholder to the fact that they have been successful identified or not as the case may be and that they no longer need to hold the card between their forefinger and thumb allowing them to push the card fully into the slot in the card reader or to remove the card and try again.

Ideally, the identification cards are manufactured using injection moulding.

Preferably, the injection moulding techniques comprise double in mould labelled injection moulding using through-hole printing of conductive ink on thin film substrate layers and providing inter-connectivity across layers.

Preferably, the software control module has algorithms with means for generating a unique bioelectrical impedance signature for a specific card holder from a full set of data including thumb-forefinger only loop, skin resistivity, sweat, geographical regionality, weight, age, gender, current, voltage measurement and frequency range. The algorithms may combine the impedance with other biometric data as may be required (e. g. since the user is presenting finger and thumb on the card, those fingerprints may be captured and collated as part of a biometric signature).

Ideally, the algorithms are capable of reducing the time required to identify a live cardholder by utilising a subset of data selected from any combination of the above variables.

Preferably, the card is dimensioned to meet DIN EN 150 9002 namely 85.72 mm x 54. 03 mm.

The present invention also provides a card-reader for use with the above described identification card, the card-reader having means for transmitting electrical power onto electronic circuitry of the identification card to initiate the identification process

at a predetermined position of travel of the card into a card reader slot or along a swipe of the card reader.

Preferably, the card reader also comprises means for confirming that the person inserting the card has been successfully identified before allowing a transaction to proceed.

Accordingly, the present invention also provides a method of identifying a cardholder comprising the steps of an identification card generating and transmitting signals into the hand or other adjacent body parts of a person who is holding the identification card, receiving signals from the person/card holder's hand or other adjacent body parts after the signals have been attenuated by the bioelectrical impedance of the card holder's body and interpreting the attenuated signals to produce a bioelectrical impedance signature for uniquely identifying the card holder.

Preferably, the method further comprising the steps of comparing a bioelectrical impedance signature of a cardholder recorded during secure enrolment with a live bioelectrical impedance signature recorded from the current card holder's body in order to confirm that the two bioelectrical impedance signatures correlate.

Ideally, the method further comprising generating and transmitting an electrical current over a range of frequencies into the card holder's hand or other adjacent body parts and receiving the attenuated signal, reading the resulting voltage drop for each frequency of the signal, filtering the attenuated signal, converting the signal from analogue to digital and passing the digital signal for interpretation.

Preferably, the method also comprises the steps of generating and transmitting the signals in response to a card holder at least partially inserting the card into a slot in a card reader. The distance of the insertion will be under the control of the respective card reader.

Alternatively, the method also comprises the step of generating and transmitting the signals in response to a card holder holding the card between the thumb and forefinger for a predetermined period of time.

The invention will now be described with reference to the accompanying drawing which shows by way of example only one embodiment of an identification card in accordance with the invention.

Referring to the drawing there is shown a bioelectrical impedance identification card indicated generally by the reference numeral 1. The card 1 comprises a cover 2 of a thin film substrate layer 3 encapsulating a polymer layer 10. A C. P. U. 4 is located within the card 1 and has an externally contactable electrode 5. Electronic control circuitry 7 is in electrical communication with C. P. U. 4 via electrical connections 6 and is also in electrical communication with a pair of externally contactable electrodes 8,9. The electrodes 8,9 are disposed on opposed main surfaces of the cover 2 of thin film substrate layer 3. One electrode 8 is formed for receiving the thumb and the other electrode 9 is formed for receiving the forefinger. Of course, the electrodes 8,9 can be formed identically so as to be suitable for receiving both the finger and the thumb.

In use, a card holder lifts the card 1 with their thumb on one electrode 8 and their forefinger on the other electrode 9. The cardholder inserts the end of the card 1 with the externally contactable electrode 5 into the slot of a card reader (not shown) and power is transmitted onto the C. P. U. 4 via electrode 5 from the card reader power source. In an alternative embodiment, the card's own power source is initiated when the card holder holds the electrodes 8,9 between their finger and thumb for a predetermined period of time. An operating system on the C. P. U. 4 boots up and a software control module is executed on the C. P. U. 4 generating and transmitting digital signals to the electronic control circuitry 7 which converts the digital signals to analogue current and frequency variable electrical signals and transmits these signals to the card holder's hand via electrodes 8,9. The bioelectrical impedance of the card holder's body attenuates the signals as they pass around the closed loop formed by the thumb and forefinger located on the opposed electrodes 8,9. When the electrodes 8,9 receive the attenuated signals the signals are passed to the electronic control circuitry 7. The electronic control circuitry 7 reads voltage values for each frequency of the attenuated signals, filters the attenuated

signals and converts them from analogue to digital and presents the signals to the software module running on the C. P. U. 4.

The software control module generates a bioelectrical impedance signature for the cardholder currently holding the card 1 from the information received from the electronic control circuitry 7. This bioelectrical impedance signature is then compared by the software control module with a bioelectrical impedance signature which has been recorded during a secure enrolment procedure for the entitled cardholder. If the signatures correlate to a degree determined to be sufficient by versatile comparison algorithms underlying a software comparison routine (intelligent agent) then an indicator on the card is powered and the card holder can proceed as normal with the transaction they wish to execute by inserting the card fully into the card reader slot or by transmitting the authorisation signal to a remote transaction unit. If the signatures do not correlate the cardholder can try again. If the identification process is unsuccessful after a number of attempts the cardholder is attempting to use a card which they are not authorised to use and a potentially fraudulent transaction has been prevented.

Variations and modifications can be made without departing from the scope of the invention as defined in the appended claims.