EP0956541A1

EP0956541A1 - Method and device for processing biometric data

Info

Publication number: EP0956541A1
Application number: EP98962199A
Authority: EP
Inventors: Frank Sellbach; Heiko Sochart
Original assignee: Orga Consult GmbH
Current assignee: Idemia Germany GmbH
Priority date: 1997-11-19
Filing date: 1998-11-03
Publication date: 1999-11-17
Also published as: DE19751172A1; DE19751172C2; BR9806780A; US6345761B1; WO1999027500A1

Abstract

The invention relates to a device for processing biometric data, especially finger print data, comprising a processing unit which has a sensor to detect a biometric input signal and means for processing said input signal in order to generate individual personalized identification data. The processing unit can be connected to a portable identification element which contains an evaluation unit enabling the personal reference data stored in a semiconductor module of said identification element to be checked against the identification data for conformity. The evaluation process consists of a similarity comparison to determine whether the identification data and the reference data coincide on the basis of a given threshold value.

Description

Description :

Device and method for processing biometric data

The invention relates to a device and a method for processing biometric data according to the preamble of patent claim 1 and patent claim 12.

A method for processing biometric data is known from EP 0 372 762 B1, in which a number of characteristic points (Mmutiae) assigned to the respective fingerprint images are compared in order to identify a fingerprint. Several fingerprint images are detected by a fingerprint sensor and the mutiae are determined as digitized data. This procedure is used for two successive fingerprints. To determine whether the fingerprints match, the mutae of the first fingerprint on the one hand and the second fingerprint on the other hand are compared. If the number of matching mmutiae is greater than a predetermined threshold value, a match of the fingerprints is assumed. A disadvantage of this method is that the fingerprints used as reference are stored unsecured in a processing unit of the device, so that manipulation of the fingerprint data is possible.

DE 44 39 593 C2 discloses a device for processing biometric data which provides for an evaluation or comparison of biometric data on the chip card. This reduces the risk of manipulation or data misuse because the data used as a reference does not leave the chip card.

A device for processing biometric data is known from DE 196 18 144 C1, biometric data associated with a person being stored as reference data on a portable identification element. These reference data are checked for agreement using identification data provided by means of a sensor. The identification data are determined from the biometric input signals of the sensor. A disadvantage of the known device is that the sensor is integrated in the portable identification element. This involves a complex card structure, which significantly increases the production costs for these cards. Because the sensor is integrally connected to the card, it is not possible to replace a defective sensor or to replace the sensor with a further developed sensor.

The object of the invention is therefore to provide a device and method for processing biometric data, so that data security is ensured in a simple manner when evaluating biometric data.

To achieve this object, the invention has the features of claims 1 and 12.

The advantage of the invention consists in particular in that a segmentation or division of a comparison program for verification purposes between the processing unit on the one hand and the portable identification element on the other hand simplifies the construction of the device. ben is. To use the biometric method, the sensor can be coupled as an additional part to existing processing units, while the physical identification element of the portable identification element remains unchanged. New security techniques, in particular on the sensor, can be easily implemented, the portable identification element only having to be configured using new software. In addition, it is inexpensive because only one sensor per processing unit is required, which is used in connection with several identification elements.

According to a further development of the invention, a parameter-dependent threshold value is specified, and if it is exceeded by the number of identified identification and reference data, a confirmation signal is sent to the processing unit. The threshold value is preferably stored in a secured memory area in the semiconductor component of the chip card, so that manipulation of the threshold value and thus avoiding the access security provided by the device according to the invention is ruled out. This ensures a high level of security in the identity check.

According to a development of the invention, security is increased in that the threshold value can only be read after an authorization program has run. In this way, only authorized persons or machines can change the threshold value. Such a change is useful in order to be able to set the level of identity control depending on the application. By designing the device according to the invention as an identification element with a single semiconductor module, the security against counterfeiting can be further increased, since the binary data or the comparison of the identification and reference data are arranged in a single chip.

Further advantages of the invention result from the further subclaims.

Two embodiments of the invention are explained in more detail below with reference to the drawings.

Show it:

FIG. 1 shows a schematic illustration of the device according to the invention according to a first exemplary embodiment,

FIG. 2 shows a schematic illustration of the device according to the invention according to a second exemplary embodiment,

FIG. 3 shows a flow diagram of the method according to the invention,

Figure 4 is a schematic representation of the device according to the invention according to a second embodiment and

FIG. 5 shows a block diagram of the structure of an algorithm running in the comparison program.

The device according to the invention can be used to check the identity of people. As can be seen from FIG. 1, the device according to the invention consists of a processing unit 1 which has an optical sensor 2 for detecting a fingerprint. Alternatively, the sensor 2 can also be designed as a thermal or electronic sensor. The input signal of sensor 2 is fed in digitized form to a computing unit 4, in which characteristic points of the fingerprint (minutiae) are derived from the image data and stored in a storage unit 5 for intermediate storage or buffering. The minutiae are stored in the storage unit 5 as identification data with information about the coordinates thereof and the orientation (angle) and the type of the same in binary form.

Minutiae of the person to be identified are stored in binary form in a semiconductor component 6 of a chip card 7 as reference data. Furthermore, a comparison program is stored in the semiconductor module 6, by means of which a comparison of the detected identification data and the reference data takes place on the chip card 7.

FIG. 3 shows how the comparison program is embedded in the comparison method according to the invention. First, the chip card 7 is inserted into the card slot provided for this purpose in the processing unit 1, wherein contacts of a card reader 8 integrated in the processing unit 1 press on the contact field of the chip card 7. After a fingerprint has been carried out by sensor 2, a grayscale image S1 is created using graphic and mathematical methods. In a further step S2, the characteristic points (minutiae) are obtained, they being in binary form and being processed directly or can be stored in the storage unit 5 for temporary storage.

In the subsequent steps S3 and S4, the detected minutiae are matched to one another or aligned with one another as identification data with the reference data to be compared stored on the chip card 7. For this purpose, a scaling of the identification data based on the reference data is carried out in step S3 and a rotation of the identification data is carried out in step S4. These operations are carried out in the computing unit 4 of the processing unit 1. As

Identification data are read out by the chip card 7 selected but not individualizing reference data required for the alignment. For example, a "delta point" on the thumb is selected as a reference for scaling, which occurs in the same place in most people.

After the identification data has been aligned with the reference data, the identification data are written into the semiconductor module 6 of the chip card 7 which has a microprocessor. The comparison process in the chip card 7 is started, the number of locally matching identification and reference data being determined, S5. The coordinates, the angle, the offset of the corresponding minutiae of the identification data on the one hand and the reference data on the other hand are compared as comparison criteria. The number of lines or finger grooves arranged between corresponding minutiae can also be used as a comparison criterion. Each of these comparison criteria is weighted with a coefficient between 0 and 1. Based on the type of fuzzy logic, a resultant comparison value is determined from the sum of the weighted decision criteria, which has a predetermined decision threshold value, which also depends on the predetermined degree of data security can be weighted, is compared. Only in the event that the comparison value is greater than the decision threshold value, a confirmation signal confirming the identification is sent to the processing unit. In the other case, a non-confirmation signal is emitted, so that a new comparison process may have to be started.

To determine the identification data, a plurality of fingerprint images are preferably checked for identity with one another in the processing unit 1. This takes place in the manner described above, equivalent to the comparison program running on the chip card 7. Only when a predetermined number ensures that several identification data of different fingerprint images match in the course of a preselection that complete identification data is available, are the relevant identification data evaluated with the reference data on the chip card 7 by comparison on the chip card 7.

The semiconductor module 6 is designed in such a way that comparison programs that may have been changed or matched to another sensor can be stored in the latter. It is provided that only part of the evaluation or verification takes place on the chip card 7. However, the part of such a comparison program that takes place in processing unit 1 may only process a limited number of individualizing reference data.

According to a further exemplary embodiment of the invention according to FIG. 2, a sensor field 11 is arranged on the chip card 10 on a chip card 10 in addition to the semiconductor module 6 which is to be used for the evaluation shown above. An electrical connection closes flush with the top of the chip card 10. trostatic sensor, below which is directly connected a processing unit (not shown) which carries out the operations preparing for the evaluation. The actual evaluation for identity then takes place in the semiconductor module 7. When the match is established, a confirmation signal is sent to an external terminal by means of a coil 12 integrated in the chip card 7, which, for example, causes the door to open. The chip card 10 receives the energy for evaluation and data transfer from a corresponding coil of the terminal, so that the identification can only be carried out in the vicinity of the terminal. A time recording program is integrated in the program running on the chip card 10 and records the point in time at which the fingerprint is detected in the sensor. If the evaluation takes place later than a preset period of time, the confirmation signal is not sent. In this way it is ensured that only the fingerprints detected in the area of the terminal are evaluated and access by third parties is prevented as a result of the fingerprint of the authorized person being stored beforehand.

According to a further exemplary embodiment according to FIG. 4, the device consists of a sensor unit 15, in which a sensor 16 and a signal and data processing unit 17 are integrated. The input signal can already be digitized in the sensor 16. The signal and data preparation 17 of the data extracts the minutiae as identification data from the signal supplied by the sensor 16 and, when requested by a control unit 18, takes this into account, taking into account individual data relevant to the control unit 18 provided by a chip card 19, to the data on a semiconductor module 20 Chip card 19 stored reference data. The identifier now available for the comparison process Data are encrypted in an encryption unit 21 and then fed to the semiconductor module 20 of the chip card 19. The identification data is decrypted in this and then subjected to the comparison process described above. The key for the encryption taking place in the encryption unit 21 is transmitted from the semiconductor module 20 to the encryption unit 21. The control unit 18 controls the communication between the sensor unit 15 and the chip card 19. After the end of the comparison process, the confirmation signal with an electronic signature and possibly further data about the INSI number of the chip card 19 or the evaluation results is then transmitted to the control unit 18 . The control unit 18 will pass on a corresponding control signal for opening a door. Furthermore, data about the content of the chip card 19 or the communication thereof with the sensor unit 15 can be stored in a log book of the control unit and kept for documentation.

According to a variant of the exemplary embodiment according to FIG. 3 or FIG. 4, the sensor unit 15 with the signal / data processing 17 can be integrated together with the evaluation unit on a single semiconductor module 20 (chip), only the sensor 16 being flush with an upper side of one Completes the chip card and the semiconductor module 20 is embedded in the card body. This further increases the security against counterfeiting. In addition to identifying a person, the device can also be used to identify animals or objects as identifiers.

According to a special embodiment of an algorithm 30 performing the similarity comparison according to FIG. 5, it is divided into a main part 31 and a secondary part 32. is divided, the sensitive data (sensitive reference data and / or sensitive identification data) being processed in the secondary part 32. The secondary part 32 runs in a secured part of the device, preferably in the semiconductor component 6 of the chip card. The sequence of the algorithm 30 can be provided as follows. In a first main part 31 of the algorithm 30 running in the computing unit 4, such input data 33 and reference data 34 are processed as input variables, which are sufficient for a comparison or a coordination of the identification data and reference data.

In the adjoining part 32 which follows thereupon, the similarity comparison takes place with sensitive reference data 35 or individualized to a high degree with the person, which are stored on the chip card 7, and the corresponding supplied identification data 36. The algorithm 30 is then continued in the main part 31, output data 37 of the secondary part 32 being supplied as encrypted data. Further processing takes place there with the indication to the processing unit as to whether a match between the identification and reference data has been determined.

Alternatively, the main part 31 can also comprise a first part of the verification steps, subsequent intermediate steps of the comparison program running in the semiconductor module 6 in the secondary part 32. The intermediate result obtained in this way is transmitted to the computing unit 4 of the processing unit 1, further steps for verification being carried out there subsequently. This segmentation of the processing steps in the processing unit 1 on the one hand and the chip card 7 on the other hand can continue several times. It is essential here that the last processing step in the semiconductor module 6 of the card 7 takes place. follows and that a final confirmation signal is then sent to the processing unit 1 for activation. This segmentation can advantageously achieve that, if the first steps carried out in the processing unit lead to a negative result, communication between processing unit 1 and chip card 6 can be terminated without completely sensitive data being read out of chip card 6 had to.

Claims

claims

1. Device for processing biometric data, in particular fingerprint data,

with a processing unit which has a sensor for detecting a biometric input signal and means for processing the input signal for generating identification data individualizing a person,

with a portable identification element with a semiconductor module in which reference data assigned to a person are stored, and

- With a means so that the reference data stored in the portable identification element can be checked for correspondence with the identification data, characterized in that a comparison program checking the correspondence, on the one hand, runs in a first in a computing unit (4) of the processing unit (1) Part (31) and the other in one in the semiconductor device

(6) the further part (32) of the identification element (7) is divided,

2. Device according to claim 1, characterized in that the particularly sensitive identification data and reference data in the on the semiconductor chip of the identification element

(7) located part (32) can be processed.

3. Apparatus according to claim 1 or 2, characterized in that the parts (31, 32) each consist of verification steps or verification processes.

4. Device according to one of claims 1 to 3, characterized in that the last verification step of the comparison program takes place in the semiconductor module and that a confirmation signal from the semiconductor module can then be emitted to the processing unit if the result is positive.

5. Device according to one of claims 1 to 4, characterized in that the comparison program comprises a similarity comparison in which parameter-dependent comparison values are compared with a predetermined decision threshold value, so that, depending on the comparison, the correspondence between the identification data and the reference data can be determined.

6. Device according to one of claims 1 to 5, characterized in that weighted comparison values are formed within the parts (31, 32) and that when the sum of the comparison values above the decision threshold value is exceeded, the confirmation signal from the semiconductor module (6) to the processing unit ( 1) is transferable.

7. Device according to one of claims 1 to 6, characterized in that the decision threshold is stored in a secure memory area of the portable identification element (7, 10) and / or the processing unit (1).

8. Device according to one of claims 1 to 7, characterized in that in the processing unit (1) before the similarity comparison (S5) there is an adaptation between the data set of the identification data and the reference data, only a number of non-individualizing reference data from the semiconductor module (6) is transferred to the processing unit (1).

9. Device according to one of claims 1 to 8, characterized in that the sensor is designed as an optical, thermal or electronic sensor.

10. Device according to one of claims 1 to 9, characterized in that the portable identification element (7, 10) is designed as a chip card with a microprocessor which has the semiconductor module (6) and a contact surface which is flush with the top of a card body, and that a card reader (8) is integrated in the processing unit (1) for reading and writing to the semiconductor module (6).

11. Device according to one of claims 1 to 10, characterized in that the confirmation signal generated by the semiconductor chip (6) is provided with an electronic signature.

12. A method for processing biometric data, in particular fingerprint data, wherein a plurality of biometric input signals are detected in a sensor that identification data are formed from the input signal, characterized in that the identification data are transmitted into a semiconductor component (6) of a portable identification element (7) and that the identification data in the semiconductor device (6) are compared with the reference data stored in the same and that, depending on the parameter-dependent comparison, a confirmation signal is emitted by the semiconductor module (6).

13. The method according to claim 12, characterized in that the identification data in the semiconductor module (6) are compared by a similarity comparison with the reference data.

14. The method according to claim 12 or 13, characterized in that a coordination between the identification data and the reference data takes place in the processing unit (1) before the similarity comparison.