JP3564673B2 - Personal authentication system, personal authentication card and center device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention prevents unauthorized access to a center device such as a service center when using an advanced and important service using communication, such as a bank cash service, and reduces the legitimacy of each user. It is related to the authentication technology to be confirmed.
[0002]
[Prior art]
When an individual is authenticated by a magnetic card, an IC card, or the like in a bank cash service or the like, the first conventional method is to provide a personal identification number to a user in order to prove that the card has been used by the owner. Is entered. In this case, the card owner needs to store a predetermined password, and there is a trouble that the card holder must store the password.
[0003]
[Problems to be solved by the invention]
In other words, in the first conventional method, since personal authentication is performed using secret information such as a password stored only by the authorized owner, it is necessary for the personal authentication card owner to secretly store the personal identification number. There's a problem.
[0004]
As a method of avoiding this complexity, a second conventional method of authenticating an individual using a fingerprint instead of using a password has been proposed.
[0005]
In the second conventional example, a means for reading a fingerprint such as a scanner, a means for storing a fingerprint of a user to be authenticated in advance, and a means for determining whether the read fingerprint matches the stored fingerprint are provided. Is provided.
[0006]
However, since these means are provided independently of the center device, there is a problem that fingerprint information stored in each card may be stolen. In addition, it is necessary to exchange the fingerprint information between the terminal device using the card and the center device via a cable or the like, and secret information relating to the fingerprint information leaks outside via the cable. There is a problem of danger.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a personal authentication system, a personal authentication card, and a center device that can eliminate the trouble of secretly storing a personal identification number and that can prevent fingerprint information from being stolen from a card or a cable. It is assumed that.
[0008]
[Means for Solving the Problems]
The present invention provides a fingerprint reading means for reading a fingerprint, and an encryption key for generating an encryption key consisting of an encryption key and a decryption key in a public key cryptosystem according to a combination of the fingerprint read information and an attribute of a personal authentication card. The personal authentication card has a generating means and an encrypting means for encrypting predetermined information with an encryption key of the generated encryption key, and the encrypted predetermined information and the non-encrypted The terminal device has signal transmitting means for transmitting the predetermined information and the user ID corresponding to the read fingerprint, and decrypts the encrypted predetermined information corresponding to each user. A public key management means for preparing a decryption key to be used in advance and storing the decryption key in advance as a public key; and a public key management means corresponding to the user ID transmitted from the communication network. Read from A decryption means for decrypting the encrypted predetermined information transmitted through the communication network by using the public key, a predetermined information decrypted by the decryption means, and a transmission through the communication network; The center authentication apparatus has a comparison unit that compares the encrypted predetermined information and the comparison unit that determines that the personal authentication has been performed when the two match.
[0009]
Embodiments and Examples of the Invention
FIG. 1 is a block diagram showing a personal authentication system RS1 according to one embodiment of the present invention.
[0010]
The personal authentication system RS1 includes a personal authentication card 10, a terminal device 20, a communication network 30, and a center device 40.
[0011]
The personal authentication card 10 includes a fingerprint reading unit 11, an encryption key generation unit 12, an information storage unit 13, an encryption unit 14, and a communication control unit 15.
[0012]
The fingerprint reading unit 11 detects pressure or the like minutely when a user's finger is pressed, and reads image information (fingerprint information) of a fingerprint.
[0013]
The encryption key generation unit 12 has an attribute of the personal authentication card 10 and generates an encryption key corresponding to a combination of the fingerprint information read by the fingerprint reading unit 11 and the attribute of the personal authentication card 10. The “encryption key” includes an “encryption key” and a “decryption key”. In the above embodiment, the attribute of the personal authentication card 10 is a prime number extracted by the fingerprint feature amount conversion unit 50 and the prime number table T as shown in FIG.
[0014]
The information storage unit 13 stores predetermined information as the message M (the message M includes the ID number of the user).
[0015]
The encryption unit 14 encrypts predetermined information using an encryption key among the encryption keys generated by the encryption key generation unit 12.
[0016]
The communication control unit 15 is a communication control unit that transmits the ID of the user of the personal authentication card 10, the encrypted predetermined information, and the non-encrypted predetermined information.
[0017]
The terminal device 20 includes a communication unit 21 that communicates with the center device 40 via the communication network 30. The communication unit 21 sends the encrypted predetermined information, the non-encrypted predetermined information, and the user ID corresponding to the read fingerprint to the center device 40. Although FIG. 1 shows only the communication unit 21 as the terminal device 20, the terminal device 20 has other functions, and these are omitted from the illustration.
[0018]
The center device 40 includes a public key management unit 41, a decryption unit 42, and a comparison unit 43.
[0019]
The public key management unit 41 is means for storing a public key corresponding to each user. The decrypting unit 42 is encrypted by the encrypting unit 14 by using the public key read from the public key managing unit 41 corresponding to the user ID transmitted from the communication network 30, and Is a means for decoding the predetermined information transmitted via the.
Steps;
The comparing unit 43 compares the predetermined information decrypted by the decrypting unit 42 with the predetermined information transmitted via the communication network 30 and not encrypted, and determines that the personal authentication has been performed when the two match. Means.
[0020]
FIG. 2 is a diagram illustrating the encryption key generation unit 12 in the personal authentication system RS1.
[0021]
The encryption key generation unit 12 converts the read fingerprint information into a fingerprint characteristic amount by a function F into a fingerprint characteristic amount conversion unit 50 and a plurality of prime numbers p, q, u, v, w,. And a prime number table (prime number storing means) for outputting two prime numbers p and q corresponding to the fingerprint feature amounts output by the fingerprint feature amount converting means from the plurality of prime numbers. .
[0022]
In the above embodiment, the RSA encryption method, which is one of the public key encryption methods, is used as the encryption method.
[0023]
Next, the personal authentication operation in the above embodiment will be described.
[0024]
First, the user presses a finger on the fingerprint reading unit 11 on the personal authentication card 10 to read fingerprint information. The read fingerprint information is sent to the encryption key generation unit 12, and the fingerprint information is converted into a fingerprint feature by a function F. According to the converted fingerprint feature, two prime numbers p and q are obtained from the prime number table T. Is output. The prime number table T is printed with, for example, a 51-digit prime number, and the prime numbers stored in the prime number table T or the arrangement thereof are different for each personal authentication card 10. In addition, the function F is made so that when the finger is applied to the fingerprint reading unit 11, the function value does not fluctuate depending on the application method and the pressure.
[0025]
In the above case, since the fingerprint information differs for each user and the contents of the prime number table T in the encryption key generation unit 12 differ for each personal identification card 10, the two prime numbers p and q output by the encryption key generation unit 12 Is uniquely determined according to the combination of the user and the personal identification card 10 as a result. In other words, when another user uses the personal authentication card 10, another set of prime numbers (for example, r and s) is selected.
[0026]
Then, the prime numbers p and q output from the encryption key generation unit 12 are sent to the encryption unit 14. The encryption unit 14 generates the public keys e and N required for the RSA encryption method and the decryption key d according to the prime numbers p and q as follows.
[0027]
First,
N: product of prime numbers p and q,
L: least common multiple of p-1 and q-1,
e: a prime number with L,
d: a number that satisfies 1 = Lc + ed for L and e.
[0028]
That is, the least common multiple L of (p-1) and (q-1) is obtained, the public key e is obtained as a prime number with this least common multiple L, and the remaining public key N is obtained by p × q = N. Ask. Further, a decryption key d satisfying 1 = Lc + ed is obtained. This procedure is disclosed in, for example, "Ota, Kurosawa, Watanabe: Science of Information Security. 1995. Kodansha. Pp. 133".
[0029]
Note that the public keys e and N are stored in the public key management unit 41 corresponding to the user ID numbers.
[0030]
By the way, the information storage unit 13 stores communication messages M exchanged with the center device 40. This message M is stored in a predetermined format with the center device 40. For example, the serial number of the personal authentication card 10 (ID number), the personal ID number of the user, and the serial number of the card reader (ID) No.), use start time, and other information are included in the message M.
[0031]
The encryption unit 14 receives the encryption key from the encryption key generation unit 12 and converts the outgoing communication message M (plaintext) into the ciphertext X. in this case,
X = M ＾ d (mod N)
Use the formula Here, x ＾ y is x to the power of y, z (modw) is the remainder of dividing z by w, and d is the decryption key.
[0032]
Further, the communication control unit 15 uses the communication unit 21 of the terminal device 20 to center the cipher text X and the communication text M (including the plain text corresponding to the cipher text X and the user ID) using the optimum protocol. Transmit to the device 40.
[0033]
Next, a user authentication operation in the center device 40 will be described.
[0034]
First, the decryption unit 42 extracts a user ID, specifically, a user ID number h from the received message M, and a public key management unit corresponding to the extracted user ID number h. The public keys e and N stored in 41 are read from the public key management unit 41. Then, the ciphertext X received by the center device 40 is decrypted into a plaintext M ′ according to the equation of M ′ = X ＾ e (modN).
[0035]
The comparing unit 43 checks whether or not the plaintext M ′ decrypted in this way matches the message M received without encryption, and the decrypted plaintext M ′ and the message received without encryption are compared. If the sentence M matches, the center device 40 authenticates that the sender of the cipher text X is an authorized user.
[0036]
Here, it is assumed that a third party illegally steals the public keys e and N from the center device 40 and further attempts to perform personal authentication. However, in the RSA cryptosystem, it is practically almost impossible to derive the prime numbers p and q based on the public keys e and N, and with the current computational capability, based on the public keys e and N, It is said that it takes more than several hundred years to derive the prime numbers p and q. In the above embodiment, the ciphertext X required for personal authentication cannot be created because the ciphertext X cannot be derived from the plaintext M without the information of the prime numbers such as the prime numbers p, q, and d. In addition, the ciphertext X to be decrypted by the decryption unit 42 of the center device 40 cannot be sent to the decryption unit 42, and personal authentication cannot be illegally performed.
[0037]
In the above embodiment, the message M sent from the terminal device 20 to the center device 40 includes information on the time at which personal authentication is started by the personal authentication card 10, that is, information on the use start time. In the device 40, the difference between the use start time and the actual time is calculated, and if the time of this difference exceeds a predetermined time, personal authentication is not performed. That is, even if a third party illegally steals the encryption key, the message M, etc. while the authorized user is performing personal authentication using the personal authentication card 10, the third party thereafter If the user attempts to perform personal authentication, the time is later, and therefore personal authentication is not performed, and the security is high.
[0038]
Further, in the above embodiment, when an unauthorized third party illegally obtains the personal authentication card 10 and tries to start communication by impersonating an authorized user, the fingerprint information output by the fingerprint reading unit 11 is: Since the fingerprint information is different from the fingerprint information of a regular user, the combination of prime numbers selected by the function F is something other than p and q, and the encryption encrypted with such prime numbers cannot be decrypted in the center device 40. There is no personal authentication.
[0039]
By the way, in the above embodiment, since the fingerprint information of the user does not go out of the personal authentication card 10 and is not stored anywhere in the personal authentication card 10, the fingerprint information of the legitimate user is stored in the third card. Will not be stolen. In addition, since the fingerprint information of the user is not stored in the center device 40, the fingerprint information of the authorized user is not stolen by a third party from this point.
[0040]
Furthermore, by obtaining the personal authentication card 10 itself, opening the case of the personal authentication card 10 and viewing the internal information, the contents of the prime numbers p and q, the function F, and the prime number table T may be found. The following can be considered as a countermeasure for this.
{Circle around (1)} A mechanism that does not allow the contents of the prime number table T to be read out of the card directly is added to the personal authentication card 10.
{Circle around (2)} When the personal authentication card 10 is opened, a configuration is adopted in which all information stored in the personal authentication card 10 is lost.
{Circle around (3)} By increasing the number of entries of the prime numbers on the prime number table T, the probability of finding the correct set of prime numbers p and q is reduced, and this confirms that the correct set of prime numbers p and q are found. Effectively make it difficult.
[0041]
In the above embodiment, the information output by the encryption key generation unit 12 is an appropriate prime number assigned by the fingerprint information and the personal authentication card 10, and is merely information for encryption. Therefore, even if the prime number is eavesdropped and decrypted, the fingerprint information itself is not stolen by an unauthorized third party. In the above embodiment, the maintenance person of the center device 40 and the owner of the personal identification card 10 cannot actually know their own fingerprint information.
[0042]
In the above embodiment, the same operation as described above is performed even if the contents of the prime number table T in the encryption key generation unit 12 are the same in any personal identification card 10.
[0043]
【The invention's effect】
According to the present invention, fingerprint information itself, which is secret information necessary for personal authentication, does not go outside the personal authentication card and is not stored and stored anywhere in the personal authentication card, which can be a serious problem. There is an effect that there is no danger of leaking personal fingerprint information itself.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a personal authentication system RS1 according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an encryption key generation unit 12 in the personal authentication system RS1.
[Explanation of symbols]
10. Personal authentication card,
11 fingerprint reader,
12 ... an encryption key generation unit
13 Information storage unit
14 ... Encryption unit,
20 ... terminal device,
40 ... Center device,
50: fingerprint feature amount conversion unit
T: prime number table.

Claims (7)

Fingerprint reading means for reading a fingerprint;
Encryption key generation means for generating an encryption key composed of an encryption key and a decryption key in a public key cryptosystem according to a combination of the read information of the fingerprint and the attribute of the personal authentication card;
Encryption means for encrypting predetermined information with an encryption key among the generated encryption keys;
Has a personal authentication card,
The terminal device has signal transmitting means for transmitting the encrypted predetermined information, the non-encrypted predetermined information, and a user ID corresponding to the read fingerprint,
Public key management means for preparing in advance a decryption key to be used for decrypting the encrypted predetermined information corresponding to each user, and storing this in advance as a public key;
By using the public key read from the public key management means corresponding to the user ID transmitted from the communication network, the encrypted predetermined key transmitted through the communication network is used. Decoding means for decoding information;
Comparing means for comparing the predetermined information decrypted by the decryption means with the non-encrypted predetermined information transmitted via the communication network, and determining that personal authentication has been performed when the two information match;
The personal authentication system characterized in that the center device has the following. In claim 1,
The personal authentication system, wherein the attribute of the personal authentication card is different for each personal authentication card. In claim 1,
The encryption key generation means includes:
Fingerprint feature amount conversion means for converting the read information of the fingerprint into a fingerprint feature amount by a predetermined function;
Prime number storage means for storing a plurality of prime numbers and outputting a prime number corresponding to the fingerprint feature quantity output by the fingerprint feature quantity conversion means from the plurality of prime numbers;
Personal authentication system characterized by having. In claim 1,
The personal authentication card sends the time at which the fingerprint was read to the center device, and the center device determines that the difference between the time sent from the personal authentication card and the time to be compared by the comparing means is predetermined. The personal authentication system is characterized in that it is not determined that the individual has been authenticated if the time difference is exceeded. Fingerprint reading means for reading a fingerprint;
Encryption key generation means for generating an encryption key composed of an encryption key and a decryption key in a public key cryptosystem according to a combination of the read information of the fingerprint and the attribute of the personal authentication card;
Encryption means for encrypting predetermined information with an encryption key among the generated encryption keys;
A communication control unit for transmitting the ID of the user of the personal authentication card, the encrypted predetermined information, and the non-encrypted predetermined information;
Personal authentication card characterized by having. In claim 5,
When the personal identification card is opened, the attribute of the personal authentication card is lost. Public key management means for creating in advance a decryption key to be used when decrypting the encrypted predetermined information corresponding to each user, and storing this in advance as a public key ;
Corresponding to the ID of the user transmitted from the communication network, by using the public key read out from the public key management means, decoding predetermined information encrypted transmitted via the communication network Decoding means to perform;
Comparing means for comparing the predetermined information decrypted by the decrypting means with the non-encrypted predetermined information transmitted through the communication network, and determining that the personal authentication has been performed when the two information match;
A center device comprising:

Images