Abstract:
An authentication system for authenticating a particular individual using a recording medium containing information for identifying the individual has a recording medium issuing apparatus including, a database for storing a feature value usable for identification of the individual to be authenticated with the recording medium, means for managing the database to store the feature value of the individual to be authenticated with the recording medium and for generating search information to retrieve the feature value of the individual from the database, means for generating cryptographic information by encrypting the thus generated search information using a private key based on public key cryptography, and means for recording the thus generated cryptographic information and certification information concerning the individual onto the recording medium; and a recording medium authenticating apparatus including, means for decrypting the cryptographic information recorded on the recording medium using a public key paired with the private key to decode the search information, and means for searching the database using the thus decoded search information to retrieve the feature value of the individual.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a recording medium containing information for authenticating a particular individual, and more particularly to a technique for preventing forgery of authenticating information. 
     As recording media containing information for authenticating the identity of particular individuals, such as individual persons, there are various identification cards, such as drivers&#39; licenses, passports, and employee identification cards, including a diversity of certificates of authenticity. These recording media are objects made of paper or the like on which character or photographic information for individual authentication is recorded by printing or handwriting so as to allow direct visual recognition. 
     In most cases, information for individual authentication comprises information identifying a particular individual and information certified therefor. For instance, in a passport, a photograph of the face of an individual person is attached as information identifying the individual person, and the name, address, date of birth, nationality, etc. of the individual person are entered as information certified therefor. 
     In authentication, an individual is identified by identification information recorded in a recording medium, and then certification information concerning the identified individual, which is also recorded in the recording medium, is confirmed for the identified individual. In the case of authentication of a passport, a certifying officer of an immigration/emigration bureau at an airport checks facial features of a holder of the passport against a photograph of the face attached in the passport, and if the holder of the passport is identified, the certifying officer confirms the name, address, date of birth, nationality, etc. recorded in the passport for the holder thereof. 
     Sometimes, various identification cards, such as drivers&#39; licenses, passports and employee identification cards, including a diversity of certificates of authenticity, may be counterfeited for an illegal purpose. A passport, for example, may be forged for the purpose of illegal immigration, smuggling, or passage of a criminal. Therefore, there is a social demand for ensuring prevention of forgery of these identification cards and certificates. 
     Although various methods for preventing forgery have been devised heretofore, no satisfactory countermeasure against forgery has been realized yet. It is rather difficult to detect a forged passport containing a replaced photograph of a person&#39;s face, for example, giving rise to considerable problems. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a recording medium containing information for authenticating an individual and an authentication system using the same for enabling effective prevention of forgery of information for individual identification, such as a photograph of a person&#39;s face in a passport. 
     In accomplishing this object of the present invention and according to one aspect thereof, there is provided an authentication system comprising: 
     a recording medium issuing apparatus including, 
     means for generating cryptographic information by encrypting a feature value usable for identification of each individual to be authenticated with a recording medium, using a private key based on public key cryptography, and 
     means for recording the thus generated cryptographic information and certification information concerning the individual onto the recording medium; and 
     a recording medium authenticating apparatus including, 
     means for decrypting the cryptographic information recorded on the recording medium using a public key paired with the private key to decode the feature value usable for identification of the individual to be authenticated with the recording medium. 
     In accordance with the authentication system mentioned above, as identification information of a particular individual to be authenticated with a recording medium, a feature value of the individual encrypted using a predetermined private key is recorded instead of a mere feature image of the individual represented by a photograph or the like. At the time of authentication, the feature value decoded using a public key paired with the predetermined private key employed for encryption, which is usable for identification of the particular individual to be authenticated with the recording medium, is compared with a feature value of each would-be certified individual. Unless the private key paired with the public key is known, it is extremely difficult to counterfeit feature value data of the individual, which is data encrypted using the private key and decrypted using the public key. Further, it is also very difficult to derive the private key from the public key or the feature value encrypted using the private key. Therefore, the present invention makes it possible to provide a recording medium for authentication which can effectively prevent forgery of information identifying an individual. 
     In the present invention, the individual may be a person and a feature of the individual to be used for identification thereof may be a physical feature of the person. In an application where a physical feature of a person is used for identification thereof, an image thereof to be authenticated with the recording medium may be applicable as a feature value thereof to be authenticated with the recording medium. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be more apparent from the following detailed description, when taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a block diagram showing the overall configuration of a card-issuing apparatus according to a first preferred embodiment of the present invention; 
     FIG. 2 is a block diagram showing an example of a hardware configuration of the card-issuing or the card-authenticating apparatus according to the present invention; 
     FIG. 3 is a block diagram showing an overall configuration of a card-authenticating apparatus according to the first preferred embodiment of the present invention; 
     FIG. 4 is a flowchart showing a processing procedure to be carried out by the card-issuing apparatus according to the first preferred embodiment of the present invention; 
     FIG. 5 is a diagrammatic illustration showing a transaction to be performed by the card-issuing apparatus according to the first preferred embodiment of the present invention; 
     FIG. 6 is a flowchart showing a processing procedure to be carried out by the card-authenticating apparatus according to the first preferred embodiment of the present invention; 
     FIG. 7 is a diagrammatic illustration showing a transaction to be performed by the card-authenticating apparatus according to the first preferred embodiment of the present invention; 
     FIG. 8 is a block diagram showing an overall configuration of a center apparatus according to a second preferred embodiment of the present invention; 
     FIG. 9 is a block diagram showing an overall configuration of a card-authenticating apparatus according to the second preferred embodiment of the present invention; 
     FIG. 10 is a flowchart showing a processing procedure to be carried out by the center apparatus according to the second preferred embodiment of the present invention; 
     FIG. 11 is a diagrammatic illustration showing a transaction to be performed by the center apparatus or the card-authenticating apparatus according to the second preferred embodiment of the present invention; and 
     FIG. 12 is a flowchart showing a processing procedure to be carried out by the card-authenticating apparatus according to the second preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described in detail in connection with an example in which a recording medium containing information for authenticating a individual is an identification information recording medium used for identifying an individual person. 
     In a first preferred embodiment of the present invention, an authentication system comprises at least one card-issuing apparatus for issuing an identification information recording medium and at least one card-authenticating apparatus for authenticating an individual person using the identification information recording medium issued by the card-issuing apparatus. The identification information recording medium used in the present preferred embodiment is a wearable electronic recording medium capable of recording electronic data, such as a memory card, IC card, magnetic card or any other type of electronic card. 
     Referring to FIG. 1, there is shown an overall configuration of a card-issuing apparatus  100 , which comprises an input/output part  101 , a control part  104 , a conversion part  102 , and an attaching part  103 . The input/output part  101  is used to input information from an identification information recording medium  500  into the card-issuing apparatus  100 . The contents of the identification information recording medium  500  are photograph data  110 , which is image data of the face of a person certified with the identification information received from the recording medium  500  (hereinafter referred to as a certified person), a private key  111  formed by a person or organization that assures the identity of the certified person with the identification information received from the recording medium  500  (hereinafter referred to as a certifier), and document data  113  containing the name, address, date of birth and other descriptions concerning the certified person assured with the identification information received from the recording medium  500 . The input/output part  101  is also used to record converted-value-attached document data  114  (to be described later) onto the identification information in the recording medium  500 . The conversion part  102  encrypts the photograph data  110  using the private key  111  to generate a converted value  112 . The attaching part  103  attaches the converted value  112  to the document data  113  to produce the converted-value-attached document data  114 . The control part  104  controls the above-mentioned operations of the input/output part  101 , the conversion part  102  and the attaching part  103 . 
     As shown in FIG. 2, in the practice of the present invention, the card-issuing apparatus  100  can be embodied in an electronic computer system comprising a CPU  301 , a main memory  302 , an external storage device  303   a , such as a hard disk unit, an additional external storage device  303   b , a communication control device  304 , an input device  305 , such as a keyboard or pointing device, an output device  306 , such as a display monitor, an image input device  308  for capturing image data, a card processing device  309  for processing a card  310 , which serves as an identification information recording medium, etc. In the card-issuing apparatus  100 , the card  310  corresponds to the identification information recording medium  500  which is also referred to as an electronic card  500 , and the card processing device  309  is an electronic card writer device for writing data onto the electronic card  500 . 
     As the image input device  308 , a device which inputs image data from a photograph of each certified person or a device which directly takes a photograph of each certified person and inputs image data thereof may be employed. 
     The input/output part  101 , the control part  104 , the conversion part  102  and the attaching part  103  shown in FIG. 1 are implemented as processes to be carried out on the electronic computer system by executing a program accessed by the CPU  301  from the main memory  302 . This program may be arranged as a program which is pre-stored in the external storage device  303   a  and loaded into the main memory  302  as required or a program which is pre-loaded in the main memory  302 . Alternatively, this program may be stored into the external storage device  303   a  or loaded into the main memory  302  through the external storage device  303   b  from a portable storage medium  307 , such as a CD-ROM, or through the communication control device  304  from a network connected therewith. 
     Referring to FIG. 3, there is shown an overall configuration of a card-authenticating apparatus  200 , which comprises a photographing part  201 , an input/output part  202 , a control part  203 , a conversion part  204 , and a comparison part  205 . 
     The input/output part  213  is used to input a public key  211  of the certifier, face image data  213  of a would-be certified person through the photographing part  201 , and converted-value-attached document data  210  recorded on the identification information recording medium  500 . The input/output part  213  is also used to display the result of comparison attained through the comparison part  205  (to be described later), an image represented by photograph data  212 , and document data contained in the converted-value-attached document data  210 . Using the public key  211  of the certifier, the conversion part  204  decrypts the photograph data  212  of the certified person, which has been encrypted using the private key  111  formed by the certifier and which has then been contained in the converted-value-attached document data  210 . Thus, the photograph data  212  of the certified person is restored to an original state thereof. The comparison part  205  compares the photograph data  212  with the face image data  213  by a pattern matching technique or the like, and produces the result of comparison indicating whether a degree of similarity higher than a predetermined level is found therebetween. The control part  203  controls the above-mentioned operations of the photographing part  201 , the input/output part  202 , the conversion part  204  and the comparison part  205 . 
     In the practice of the present invention, the card-authenticating apparatus  200  can also be embodied in an electronic computer system similar to that shown in FIG.  2 . In the card-authenticating apparatus  200 , the card processing device  309  is an electronic card reader device for reading data from the electronic card  500 . 
     As the image input device  308  arranged in the card-authenticating apparatus  200 , a device which inputs image data from a photograph of each would-be certified person or a device which directly takes a photograph of each would-be certified person and inputs image data thereof may be employed. 
     The respective parts shown in FIG. 3 are implemented as processes to be carried out on the electronic computer system by executing a program accessed by the CPU  301  from the main memory  302 . 
     FIG. 4 shows the processing procedure to be carried out by the control part  104  of the card-issuing apparatus  100 , and FIG. 5 shows how the identification information recording medium  500  is handled. Note, however, that FIG. 5 is a diagrammatic illustration showing a data structure scheme prepared for easy understanding of the processing procedure. 
     In the discussion given below, it is assumed that the private key  111  formed by the certifier has already been input and stored into the card-issuing apparatus  100  through the input/output part  101 . 
     As shown in FIGS. 4 and 5, for issuance of the identification information recording medium  500  for a certain person to be certified, the photograph data  110  of the person and the document data  113  containing the name, address, date of birth and other descriptions concerning the person are input through the input/output part  101  under direction of the control part  104  (step  601 ). 
     Then, through the conversion part  102 , the photograph data  110  is encrypted using the private key  111  based on known public key cryptography to generate a converted value  112  as shown in FIG. 5 (step  602 ). Finally, through the attaching part  103 , the converted value  112  is attached to the document data  113  to produce converted-value-attached document data  114 , which is then written onto the identification information recording medium  500  through the input/output part  101  (step  603 ). 
     The identification information recording medium  500 , on which the converted-value-attached document data  114  has thus been recorded, is given to and held by the person certified therewith. At a later time when authentication is required, the identification information recording medium  500  is presented by the thus certified person. 
     The following describes operations of the card-authenticating apparatus  200 . 
     FIG. 6 shows the processing procedure to be carried out by the control part  203  of the card-authenticating apparatus  200 , and FIG. 7 shows how the identification information recording medium  500  is handled. Note, however, that FIG. 7 is a diagrammatic illustration showing a data structure scheme prepared for easy understanding of the processing procedure. 
     In the discussion given below, it is assumed that the private key  111  formed by the certifier has already been input and stored into the card-authenticating apparatus  200  through the input/output part  202 . 
     As shown in FIGS. 6 and 7, when a would-be certified person presents the identification information recording medium  500  held by the would-be certified person, the converted-value-attached document data  210  is input from the identification information recording medium  500  through the input/output part  202  under direction of the control part  203  of the card-authenticating apparatus  200  (step  801 ). Then, the photograph data  212  of the would-be certified person, which has been encrypted using the private key  111  formed by the certifier and which has then been contained in the converted-value-attached document data  210 , is decrypted using the public key  211  of the certifier based on known public key cryptography through the conversion part  204 . Thus, the photograph data  212  of the would-be certified person is decoded (step  802 ). 
     Then, through the photographing part  201  and the input/output part  202 , a picture of the face of the would-be certified person is input as face image data  213  (step  803 ). Thereafter, through the comparison part  205 , the face image data  213  is compared with the decrypted photograph data  212  by a pattern matching technique or the like to produce a result of comparison indicating whether a degree of similarity higher than a predetermined level is found therebetween. Through the input/output part  202 , the result of comparison is displayed along with an image represented by the decrypted photograph data  212  and descriptions attained from document data contained in the converted-value-attached document data  210  (step  804 ). If the result of comparison indicates a degree of similarity higher than the predetermined level between the face image data  213  and the decrypted photograph data  212 , the result of comparison signifies that the would-be certified person is certainly a person certified with the identification information recording medium  500 , i.e., it is authenticated that the identification information recording medium  500  has been issued to the would-be certified person. 
     As mentioned above and according to the present preferred embodiment, photograph data of a certified person encrypted using a private key formed by a certifier is recorded onto an identification information recording medium as information identifying the certified person instead of mere photograph data of the certified person. In authentication of each would-be certified person, the encrypted photograph data is decrypted using a public key of the certifier, and the photograph data thus decrypted is compared with facial features of the would-be certified person. In such a case that the encrypted photograph data is decrypted using the public key of the certifier as stated above, it is extremely difficult to illegally forge the photograph data unless the corresponding private key formed by the certifier is known. Further, it is also very difficult to derive the private key formed by the certifier from the public key or the photograph data encrypted using the private key. Therefore, an identification information recording medium capable of effectively preventing forgery of information identifying each certified person can be provided according to the present preferred embodiment. 
     In a modified arrangement of the present invention, evaluation values of original data based on any one-way function may be used as data to be encrypted using the private key formed by the certifier. Where a one-way function such as a hash function is employed, though evaluation values calculated from data using the one-way function may be figured out, it is virtually impossible to figure out original data using the evaluation values. 
     In the present preferred embodiment mentioned above, only the photograph data of the certified person is encrypted using the private key formed by the certifier in the card-issuing apparatus  100 . In a modified embodiment of the present invention, the following arrangement may be made: The document data containing the name, address, date of birth and other descriptions concerning the certified person is also encrypted using the private key formed by the certifier and the document data thus encrypted is recorded onto the identification information recording medium. Then, in the card-authenticating apparatus  200 , the document data encrypted and recorded on the identification information recording medium is decrypted using the public key of the certifier at the time of authentication. In this manner, similar to the photograph data, the descriptions concerning the person certified with the identification information recording media can also be protected effectively against possible forgery. 
     As mentioned above, in the card-authenticating apparatus  200  in the present preferred embodiment, the face image data of the would-be certified person is compared with the image attained by decrypting the photograph data which has been encrypted by the private key of the certifier and recorded on the identification information recording medium, and the result of comparison is displayed. In a modified form of the present invention, the processing step of this comparison may be eliminated. More specifically, the image attained by decrypting the photograph data which has been encrypted by the private key of the certifier and recorded on the identification information recording medium and the document data recorded on the identification information recording medium are just displayed in the card-authenticating apparatus  200 . Then, the certifier using the card-authenticating apparatus  200  compares the thus displayed image with the actual face of the would-be certified person. The certifier can thus form a judgment as to whether the appearance of the would-be certified person is identical with the displayed image which has been attained through the decryption mentioned above. 
     Further, in a modification of the present preferred embodiment mentioned above, there may be provided an arrangement in which only the photograph data encrypted using the private key of the certifier is recorded onto the identification information recording medium and the name, address, date of birth and other descriptions concerning the certified person are indicated in a directly visible form which is non-separable from the identification information recording medium. For example, for indication of the descriptions concerning the certified person, counterfeit-resistant characters may be printed or etched on the surface of an electronic card used as the identification information recording medium. 
     Still further, while the conversion parts  102  and  204  in the present preferred embodiment mentioned above are implemented as processes to be carried out on an electronic computer system by executing programs accessed by the CPU from the main memory, it is to be understood that the present invention is not limited to such a form of implementation. For example, LSI encryption hardware and LSI decryption hardware may be used in lieu of the programs accessed by the CPU from the main memory. 
     The following describes a second preferred embodiment of the present invention. 
     In the second preferred embodiment of the present invention, an authentication system comprises at least one center apparatus and at least one card-authenticating apparatus which are mutually connected through a network. 
     As an identification information recording medium, the present preferred embodiment uses a recording medium which allows recording characters and graphics in a directly visible form by printing or the like. For example, a paper, plastic or metallic card is used as the identification information recording medium. 
     Referring to FIG. 8, there is shown an overall configuration of a center apparatus  1000 , which comprises an input/output part  1001 , a control part  1002 , a database management part  1003 , a conversion part  1004 , and an attaching part  1005 . The input/output part  1001  is used to input photograph data  1006  which is image data of a face of a person certified with an identification information recording medium  500 , a private key  1009  formed by a certifier, and document data  1111  containing the name, address, date of birth and other description concerning the certified person assured with the identification information recording medium  500 . The input/output part  1001  is also used to record converted-value-attached document data  1112  (to be described later) onto the identification information recording medium  500 . 
     The database management part  1003  manages a database  1007  containing photograph data. When each photograph data  1006  is input through the input/output part  1001 , the database management part  1003  assigns a registration number  1008  to the photograph data  1006 , which is then registered into the database  1007 . The registration number  1008  comprises a number for identifying the center apparatus  1000  used for registering the photograph data  1006 . 
     The conversion part  1004  encrypts the registration number  1008  of the photograph data  1006  using the private key  1009  to generate a converted value  1010 . The attaching part  1005  inserts the converted value  1010  (represented by a graphic barcode) into the document data  1111  to produce the converted-value-attached document data  1112 . 
     Through a network  6000 , the input/output part  1001  receives a query with a registration number from card-authenticating apparatus  2000 , and then the input/output part  1001  feeds the received query to the database management part  1003 . The database management part  1003  searches the database  1007  for photograph data corresponding to the registration number indicated in the query. When the photograph data of interest is found in the database  1007 , the database management part  1003  returns the photograph data of interest to the input/output part  1001 . Then, through the network  6000 , the input/output part  1001  sends the photograph data of interest to the card-authenticating apparatus  2000  which has issued the query. 
     The control part  1002  controls the above-mentioned operations of the input/output part  1001 , the database management part  1003 , the conversion part  1004  and the attaching part  1005 . 
     The center apparatus  1000  can also be embodied on an electronic computer system similar to that shown in FIG.  2 . In a center apparatus  1000  of this type, a card  500  equivalent to the card  310  is used as an identification information recording medium, and the card processing device  309  is a printing system for printing the cards  500 . As the image input device  308  arranged in the center apparatus  1000 , a device which inputs image data from a photograph of each certified person or a device which directly takes a photograph of each certified person and inputs image data thereof may be employed. 
     The respective parts shown in FIG. 8 are also implemented as processes to be carried out on the electronic computer system by executing a program accessed by the CPU  301  from the main memory  302 . 
     Referring to FIG. 9, there is shown an overall configuration of a card-authenticating apparatus  2000 , which comprises an input/output part  2001 , a control part  2002 , a conversion part  2003 , and a remote query part  2004 . 
     The input/output part  2001  is used to input a public key  2006  of the certifier and a converted value  2005  represented by a graphic barcode printed on the identification information recording medium  500 . The input/output part  2001  is also used to send a query issued by the remote query part  2004  to the center apparatus  1000  through the network  6000 . When the input/output part  2001  receives photograph data from the center apparatus  1000  as an answer to the query, the input/output part  2001  passes the photograph data to the remote query part  2004 . Further, the input/output part  2001  is used to display an image of the photograph data retrieved by the remote query part  2004 . 
     Using the public key  2006  of the certifier, the conversion part  2003  decrypts the converted value  2005  to attain a registration number  2007  of the photograph data. Through the input/output part  2001 , the remote query part  2004  issues a query with the decrypted registration number via network  6000  to the center apparatus  1000  which is identified by a number contained in the registration number. Thus, the photograph data corresponding to the registration number is retrieved from the database  1007  in the center apparatus  1000 , and the retrieved photograph data is supplied to the input/output part  2001  to display an image represented thereby. 
     The control part  2002  controls the above-mentioned operations of the input/output part  2001 , the conversion part  2003  and the remove query part  2004 . 
     The card-authenticating apparatus  2000  can also be embodied on an electronic computer system similar to that shown in FIG.  2 . It is not necessarily required to provide the image input device  308 . In the card-authenticating apparatus  2000 , the card processing device  309  is a barcode reader device for reading out a barcode printed on the card  500 . 
     The respective parts shown in FIG. 9 are also implemented as processes to be carried out on the electronic computer system by executing a program accessed by the CPU  301  from the main memory  302 . 
     Referring to FIGS. 10 and 11, the following describes the processing procedure to be carried out by the control part  1002  of the center apparatus  1000 . 
     In the discussion given below, it is assumed that the private key  1009  formed by the certifier has already been input and stored into the center apparatus  1000  through the input/output part  1001 . 
     As shown in FIGS. 10 and 11, for issuance of the identification information recording medium  500  for a certain person to be certified, the photograph data  1006  of the person and the document data  1011  containing the name, address, date of birth and other descriptions concerning the person are input through the input/output part  1001  under direction of the control part  1002  (step  1501 ). 
     Then, through the database management part  1003 , a registration number containing a number for identifying the center apparatus is assigned to the input photograph data  1006  as shown in FIG.  11 . The photograph data  1006  is registered into the database  1007  together with the registration number (step  1502 ). 
     Then, through the conversion part  1004 , the registration number of the photograph data  1006  registered in the database  1007  is encrypted using the private key  1009  based on known public key cryptography to generate a converted value  112  (step  1503 ). Finally, through the attaching part  1005 , the converted value  112  is attached to the document data  1011  to produce converted-value-attached document data  1112  which represents a document  1012  containing a graphic barcode. The document  1012  represented by the converted-value-attached document data  1112  is then printed onto the identification information recording medium  500  through the input/output part  1001  (step  1504 ). 
     The identification information recording medium  500 , on which the document  1012  represented by the converted-value-attached document data  1112  has thus been recorded, is given to and held by the person certified therewith. At a later time when authentication is required, the identification information recording medium  500  is presented by the thus certified person. 
     As aforementioned, when the input/output part  1001  receives a query with a registration number from the card-authenticating apparatus  2000  through the network  6000 , the control part  1002  controls the database management part  1003  to search the database  1007  for photograph data corresponding to the registration number indicated in the query. When the photograph data of interest is found in the database  1007 , the photograph data of interest is returned to the input/output part  1001 . Then, through the network  6000 , the input/output part  1001  sends the photograph data of interest to the card-authenticating apparatus  2000  which has issued the query. 
     Referring FIGS. 12 and 11, the following describes the processing procedure to be carried out by the control part  2002  of the card-authenticating apparatus  2000 . 
     In the discussion given below, it is assumed that the public key  2006  of the certifier has already been input and stored into the card-authenticating apparatus  2000  through the input/output part  2001 . 
     As shown in FIGS. 12 and 11, when a would-be certified person presents the identification information recording medium  500  held by the would-be certified person, a barcode printed on the identification information recording medium  500   20  is read out through the input/output part  2001  under direction of the control part  2002  of the card-authenticating apparatus  2000 . Then, the barcode thus read out is translated into a numeric value corresponding to a converted value  2005  (step  1007 ). 
     Through the conversion part  2003 , the converted value  2005  is decrypted using the public key  2006  of the certifier based on known public key cryptography to attain a registration number  2007  (step  1702 ). Then, through the input/output part  2001 , the remote query part  2004  issues a query with the decrypted registration number to the center apparatus  1000  which is identified by a number contained in the registration number  2007 . Thus, according to the registration number  2007 , the photograph data of interest is retrieved from the database  1007  in the center apparatus  1000  (step  1703 ). The photograph data thus retrieved is supplied to the input/output part  2001  to display an image represented thereby (step  1704 ). 
     Then, the certifier using the card-authenticating apparatus  2000  compares the thus displayed image with the actual face of the would-be certified person. The certifier can thus form a judgment whether the appearance of the would-be certified person is identical with the displayed image which has been attained through the decryption mentioned above. 
     According to the second preferred embodiment of the present invention described above, since the encrypted registration number of the photograph data is recorded onto the identification information recording medium in lieu of the encrypted photograph data, there is provided an advantage that the amount of information recorded on the identification information recording medium can be reduced substantially, in addition to the advantageous effects stated in the foregoing description of the first preferred embodiment of the present invention. Therefore, in accordance with the second preferred embodiment, information identifying the certified person can also be recorded onto a non-electronic recording medium such as a paper card by printing a barcode, for example. Further, since the center apparatus  1000  where photograph data corresponding to each registration number is registered can be identified by a number contained in the registration number received from the card-authenticating apparatus  2000 , it is possible to provide a plurality of center apparatuses  1000  as required in some applications. 
     Further, while a barcode representing each encrypted registration number of photograph data is recorded onto the identification information recording medium in the second preferred embodiment, a numeric value directly indicating each encrypted registration number of photograph data may also be recorded onto the identification information recording medium in lieu of the barcode. There may also be provided a modified arrangement in which each encrypted registration number of photograph data is electronically recorded onto an electronic recording medium used as the identification information recording medium. 
     Still further, while the conversion parts  1004  and  2003  in the second preferred embodiment are implemented as processes to be carried out on an electronic computer system by executing programs accessed by the CPU from the main memory, it is to be understood that the present invention is not limited to such a form of implementation. For example, LSI encryption hardware and LSI decryption hardware may be used in lieu of the programs loaded from the CPU into the main memory. 
     Still further, in a modification of the second preferred embodiment, the following arrangement may be made in the same fashion as in the first preferred embodiment. In the card-authenticating apparatus  200 , face image data of the would-be certified person is input and compared with the photograph data retrieved according to the registration number encrypted using the private key of the certifier which is recorded on the identification information recording medium, and the result of comparison is displayed. 
     Furthermore, while the photograph data of each certified person is used as information for identification of the certified person and an encrypted value of the photograph data or an encrypted value of the registration number of the photograph data is recorded onto the identification information recording medium in each preferred embodiment mentioned above, it is to be understood that the present invention is not limited to such a form of embodiment. 
     In a modified embodiment of the present invention, there may be provided an arrangement in which a finger print, voiceprint, iris pattern, retina pattern, height value, weight value, gene pattern, blood information or other feature information of each certified person is used individually or in combination for identification of the certified person in lieu of the photograph data or in combination therewith. 
     As set forth hereinabove, the present invention provides a recording medium containing information for authenticating a individual and an authentication system using the same for enabling effective prevention of forgery of information for individual identification such as a photograph of a person&#39;s face in a passport. 
     While the present invention has been described in detail and pictorially in the accompanying drawings, it is not limited to such details since many changes and modifications recognizable to those of ordinary skill in the art may be made to the invention without departing from the spirit and the scope thereof.