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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates to electronic shopping, electronic check
books, credit cards and the like, and particularly to an IC card which is
adapted to preventing data alteration, forgery and the like among the
traders.
The IC card which consists of a plastic card in which an IC (integrated
circuit) is embedded has functions for identifying the individual person
and for making forgery difficult, and has a large memory capacity. Such a
card finds application in electronic settlement, personal information
files, security control and the like.
When a person goes shopping in supermarkets and department stores using an
IC card, it is desirable from the standpoint of privacy that a list of
purchases made in one store not be readable in other stores in which the
person makes another purchase. For this purpose, the IC card should be
provided with transaction areas that are different depending upon the
store, so that one store is not allowed to make reference to the
transactions of other stores.
A first problem in the conventional art is that, there had been proposed
neither a method of protecting a plurality of transaction areas in the
same IC card by different encipher keys nor a key control method suited
for this purpose.
Among the public key cipher systems, on the other hand, a master key exists
in the RSA method and in the Rabin method. Using the master key, the
above-mentioned key control can be effectively carried out.
A second problem in the conventional art is that consideration has not been
given in regard to forgery of the IC card, and alteration or forgery of
data in the card.
A third problem is that the conventional IC card has been fabricated based
on a prerequisite that it be used by an individual person (see Nikkei
Computer, "Will the Age of IC Card Come?", July 8, 1985). Health
management data, property management data and like data may be input to
the IC card to utilize them. In addition to the situation where the user
himself keys in the personal identification number to obtain the desired
data, however, it may often happen that a medical doctor or a bank
employee keys in another personal identification number to take out all or
part of the desired data, such as in an emergency.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide an IC card which is
capable of protecting the data in different transaction areas in the IC
card.
A second object of the present invention is to provide an IC card which
makes it possible to detect forgery of the card, or alteration or forgery
of data in the card such as a cashless shopping credit card.
A third object of the present invention is to provide an IC card which
permits the user of the card to take out the data and which also permits
only a limited number of persons to take out the data in case of an
emergency.
In order to achieve the above first object, the present invention carries
out the below-mentioned processing in writing data onto, or in reading
data from, the transaction areas of the IC card.
(i) The IC card administrator prepares in advance sets of encipher keys and
decipher keys for a number of the transaction areas that are to be kept
secret, and prepares a master decipher key for all of the decipher keys.
(ii) The IC card administrator assigns an encipher key code and a decipher
key code for each of the transaction areas, writes an available
upper-limit amount of money and the encipher key code or the decipher key
code on a portion of the corresponding transaction area, and encrypts the
transaction area using the encipher key.
(iii) The IC card administrator hands the IC card over to the user. The IC
card administrator further hands the encipher keys and the decipher keys
to the respective individual stores so that they can encrypt and decipher
the transaction areas.
Owing to the above-mentioned procedures (i) to (iii), different encipher
keys and decipher keys are held by the different stores. Therefore, a
given store is permitted to process only the transaction areas that
correspond to the encipher key and the decipher key held by that store
from among the plurality of transaction areas contained in the IC card.
This makes it possible to protect the privacy of the user. The IC card
administrator holds the master decipher key which is capable of
deciphering all of the transaction areas in the IC card. Therefore, the
master decipher key can be used should the individual decipher keys be
lost. Furthermore, the master decipher key need not be used for the
transactions, and can be safely administered.
In order to achieve the above second object, furthermore, the data in the
card are detected by checking the balance and by checking a data
alteration detection code to detect the alteration or forgery of data.
Further, data alteration or forgery in the store transaction file or in
the bank transaction file, is checked by collating the data alteration
detection code and the IC card data.
A data alteration detection circuit in principle resembles the algorithm of
a code error detection circuit, and can be implemented by using a
crytograph apparatus and feeding the output thereof back to the input
thereof.
To achieve the above third object, furthermore, a microprocessor for the IC
card determines the permitted access relying upon the personal
identification number (codes are also acceptable in addition to numerals)
that is input, and an accessible data region is determined to output the
permitted data.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are block diagrams showing the structure of an IC card
according to a first embodiment of the present invention;
FIG. 2 is a flow chart of an operation when a user makes a purchase in a
store using the IC card;
FIG. 3 is a block diagram showing the structure of an IC card according to
a second embodiment of the present invention;
FIG. 4 is a block diagram showing the structure of the data alteration
detection circuit in the IC card;
FIG. 5 is a block diagram showing the structure of an IC card according to
a third embodiment of the present invention in an IC card system for
health management data;
FIG. 6 is a diagram illustrating the data structure in a ROM; and
FIG. 7 is a diagram illustrating the data structure in an EEROM.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1A and 1B show the manner of structuring an IC card and FIG. 2 shows
the structure of the IC card, according to a first embodiment of the
present invention.
First, preparation is carried out as described below.
An IC card administrator 101 prepares sets (102, 103), . . . , (106, 107)
of encipher keys and decipher keys, prepares a master key 108 for the
decipher keys 103, . . . , 107, and retains the master key 108 in a secure
place. Thereafter, the IC card administrator 101 hands the sets (102,
103), . . . , (106, 107) of encipher keys and decipher keys over to the
stores 109, . . . , 111. The IC card administrator, further, writes an
available upper-limit amount of money onto the transaction areas 122, . .
. , 124 of the IC card 125. The IC card administrator then encrypts the
sets (102, 103), . . . , (106, 107) of encipher keys and decipher keys
with an encipher key code that corresponds to each of the cards, and
writes each of the sets onto each of the key memories 113, . . . , 115 of
the IC card 125, and then encrypts authentication codes corresponding to
data written on each of the transaction areas with an encipher key code
that corresponds to each of the cards and writes them down. The IC card
administrator then hands the IC card 125 over to a user 116.
Here, the authentication code refers to data written on the transaction
areas, that are compressed. For instance, use is made of a MAC (message
authentication code) of U.S. ANSI Bank Association Message Authentication
Standards (FIMAS).
The data are written into a memory 119 and are read out from the memory 119
by driving a processor 117 under the control of software 120 contained in
a ROM (read-only memory) 118 via an I/O part (input and output part) 112.
FIG. 2 is a flow chart for processing the IC card when the user 116 makes a
purchase in a store 109.
201: The user inputs his personal identification number into the processor
117 via I/O part.
202: The processor 117 draws the personal identification number from a
secret area 121 under the control of software 120.
203: The processor 117 produces, via I/O part, a signal "OK" when the
personal identification number applied by the user 116 is in agreement
with the personal identification number contained in the secret area, and
produces a signal "NO" when they are not in agreement.
204: When the signal "NO" is produced, the processor 117 does not write
data or does not read data until the signal "OK" is next produced.
205: When the signal "OK" is produced, the store 109 updates the contents
of the transaction area 122, using the encipher key 102 and decipher key
103, depending upon the items which the user 116 has purchased.
Updating of the contents of the transaction area will now be described. The
code of decipher key 103 is applied to the IC card via I/O part 112 by the
store 109, and the data in the key memory 113 is deciphered. Then, it is
confirmed whether an authentication code contained in the deciphered data
is in agreement with an authentication code that is calculated from the
data of the transaction area 122. After they are confirmed to be in
agreement, the transaction area 122 and the authentication code are
updated depending upon the purchase and, then, the key memory 113 is
encrypted with the above encipher key code.
When it is found that the authentication codes are not in agreement, the IC
card produces a signal to inform the store 109 of this fact so that the
store 109 may follow the necessary procedure to inhibit the purchase.
Next, described below is an example of shopping using an IC card according
to a second embodiment of the present invention.
In this example of shopping, illegal acts may be done by altering the data
in the card, such as altering the data of cash receipts from a bank and
altering the data of sales and purchases.
FIG. 3 is a block diagram of the IC card for preventing this sort of
illegal activity.
The IC card process is not allowed to proceed to the next operation unless
the user of the IC card is confirmed by a collation circuit 1 relying upon
a password or the like. A security code 2 has been written on a read-only
memory which cannot be directly read from the external side. An account
number 3 has also been written in the read-only memory. A data alteration
detection circuit 4 forms an encrypted authentication code by feeding the
output of a cryptograph apparatus back to the input side thereof as shown
in FIG. 4. That is, if the data 61, . . . , 64 to be authenticated are
altered and are input as data 6 of FIG. 4, effects of bits of the altered
data are successively propagated forward, and a code 65 is formed that is
different from the original code. Therefore, the fact of alteration is
detected.
An input/output control circuit 5 is an interface circuit between the IC
card and the terminals 30, 31 for the card. A data file 6 is concerned
with input times, terminal numbers, cash receipts and payments, balance,
data alteration detection code and the like.
First, to write the cash receipt onto the card, the card is set to a
banking terminal 30, and a password is input from the keyboard. The
password is input through the input control circuit 5 and is collated with
the code in the circuit by the collation circuit 1, to make sure that the
user is a person who is authorized to possess the card. If the collated
result is acceptable, the account number is sent to the input/output
control circuit 5 in response to a signal from the collation circuit 1. An
account file is then opened at the banking terminal. As the cash receipt
data is input to the card from the keyboard, a security code at the
terminal is input to the card together with the cash receipt, time,
balance, and terminal number. In the card, the data that has passed
through the input control circuit is sent to the data alteration detection
circuit 4 which obtains a data alteration detection code by giving the
time, terminal number and cash receipt as inputs to the cryptograph
apparatus with the security code of the card and security code of the
terminal as keys. These data are written into file 6 and are, at the same
time, written into the account file. The security code of the terminal is
recorded on the security code area 2 of the card. Here, the security code
area is a memory region equipped with means to protect the data, using
hardware and software manners so that the data will not be available to an
outsider or the data may not be written by an outsider.
To do shopping in a store, the card is connected to a shopping terminal 31,
and a password is input through the keyboard at the shopping terminal 31.
If a proper password is applied, the shopping terminal reads the balance
from the card. After the balance is checked, therefore, prices of the
purchased merchandise are input through the keyboard at the terminal 31.
As the cash payment, time, balance, shopping terminal number and security
code at the terminal are input as described earlier, the data alteration
detection circuit 4 in the card receives time 61, terminal number 62, cash
receipts and payment 63 and balance 64 as inputs to obtain a data
alteration detection code 65 with the security codes of the card and
terminal as keys. These data are written on the file 6 and are, at the
same time, written on the store transaction file 32 together with the
account number recorded in the bank account number via the shopping
terminal 31.
The store transaction file 32 is transferred to the bank, sorted by account
numbers, and is written onto the account file 33.
As the balance becomes small and the user writes cash receipts onto the
card again, the user sets the card to the banking terminal 30 and inputs
the password. If the password is acceptable, file of the card can be read
out from the banking terminal 30. The banking terminal reads the account
number from the card and opens an account file in which have already been
written the data from the store. Therefore, permissible or impermissible
use of the card is discriminated by collating the file of the card with
the account file and by checking the balance.
If both records are correct, the records are erased from the card file.
If the records are all acceptable, the bank transfers the amount of money
which the customer has spent to the store. The balance is calculated in
the bank.
To check the balance, cash payments 63 due to each purchase are subtracted
from the initial balance of the card file, and the subtracted result is
collated with the balance 64.
When the records are not in agreement, the security code at the terminal is
read out for each of the records from the bank file relying upon the
terminal number 62 of the records. The security code and the record are
then input to the card to obtain a data alteration detection code from the
card. The collating of this code with the data alteration detection code
of the previous record of the card or of the bank file is referred to as
the checking of detection code.
It is now presumed that a record is not in agreement, the content of the
record that is not in agreement being the time. In this case, the record
of a time that is in agreement with any one of the records is found from
the card file and the bank file.
(a) The IC card contains no corresponding record, and the detection code
check of the bank record and the balance check are correct. In this case,
the card does not contain a record, and it is assumed that the record is
erased from the IC card.
(b) The IC card contains no corresponding record, and the detection code
checking of the bank record is not acceptable. In this case, the record
was added on the side of the bank, and it is considered that the record
was unfairly added to the bank file.
The same determination can also be rendered even when the record on the
side of the bank contains no corresponding record.
Next, when the record is not in agreement, the content of the record that
is not in agreement being the terminal number and the cash receipts and
payments, proper use or improper use is determined by checking each of the
detection codes.
Further, when the record is not in agreement, the content thereof being the
balance, proper or improper use is determined by checking each of the
balances.
It is also possible to use numbers such as serial numbers instead of the
time data.
According to the above-mentioned embodiment of the present invention, it is
possible to detect the alteration of data in the IC card and in the bank
file.
The IC card according to a third embodiment of the present invention will
now be described in conjunction with FIGS. 5 to 7.
FIG. 5 is a diagram which schematically illustrates the structure of an IC
card system for health management data, wherein the IC card 100 is
connected to a terminal 200 for the IC card via an interface 290, to
exhibit the functions of the IC card.
The IC card 100 consists of a microprocessor 120, an ROM (read-only memory)
110, a PROM (programmable read-only memory) 130, and an EEPROM
(electrically erasable programmable read-only memory) 140, which are
connected together via signal lines 150. As the IC card 100 is connected
via a signal line 160 to the terminal 200 for IC card, a program in the
PROM 130 is loaded in the microprocessor 120 so that it can be used.
The terminal 200 for the IC card consists of a microcomputer 240, a
keyboard 210 and a display 220, that are connected together through signal
lines 170. The microcomputer 240 is further connected to a data management
center 400 via a signal line 180, a MODEM 310, a public telephone line 320
and another MODEM 330. The data management center 400 consists of a
computer 410 and a data base 420.
A possessor of the IC card 100 may visit a doctor who is not his family
physician, and properly inputs his personal identification number through
the keyboard 210. The signal is then sent to the microprocessor 120 in the
IC card via the microcomputer 240 on the side of the terminal 200. The
microprocessor 120 searches through the ROM 110.
Here, the ROM 110 has a data structure as shown in FIG. 6. That is, the
data structure consists of a personal identification number 111 of the
possessor of the IC card 100, a permission level 112 of information
reference of the possessor, license codes 113 of the medical practice of
the registered doctors, their personal identification numbers 114, their
permission levels 115 of information reference, authentication codes 117
of the data of the registered doctors, and a permission level 116 of
information reference for non-registered doctors.
If the microprocessor 120 which searches through the ROM 110 indicates that
the personal identification number that is input is in agreement with the
personal identification number 111 of the possessor, the permission level
112 of information reference is read out. It is presumed that there exists
only one level 1. Based upon this level, the microprocessor 120 reads the
data file in the EEPROM 140.
FIG. 7 illustrates a data structure in the EEPROM 140. Here, it is presumed
that the data A (accessible with level 1 and level 2) 141 and the data B
(accessible with level 1 only) 142 are contained in the EEROM 140. For
instance, the data A 141 contains data necessary for the diagnosis and
therapy, such as blood type, diagnosis result of medical examination,
medical history, and the like. The data B 142 contains such data as family
structure and the like, that have no direct relation to the diagnosis or
therapy, as well as those data which the possessor of the card may not
wish to have known to other persons without his permission.
In this case, the level 1 is given by the microprocessor 120 to make access
to the data A 141 and the data B 142. The data are sent from the
microprocessor 120 to the microcomputer 240 for terminal, 200 subjected to
processing for display, and are displayed on the display unit 220. The
data are also displayed for the doctor to be utilized for the diagnosis
and therapy. Part of the results is also input through the keyboard 210,
and is written onto the data A 141 or the data B 142 in the EEPROM 140 via
microcomputer 240, microprocessor 120 and the like.
Here, it may happen that the possessor of the IC card 100 needs emergency
therapy due to, for example, a traffic accident, the possessor not being
able to input his personal identification number by himself. In this case,
the doctor inputs the code of his license code of practice medicine and
his personal identification number through the keyboard 210. The input
results are sent to the microprocessor 120 in the IC card 100 via the
microcomputer 240. The microprocessor 120 prepares an authentication code
with the personal identification number 114 as a key and with the file
data of the registered doctor as an input data, determines whether the
thus prepared authentication code is in agreement with the authentication
code 117 that is written in the file data, compares the license code 113
for the practice of medicine and the personal identification number 114 of
the registered doctor in the ROM 110 with the license code for the
practice medicine and the personal identification number that are input.
When they are in agreement, the microprocessor 120 reads the permission
level 115 of information reference and reads the data that meets the
permission level from the EEPROM 140. The result is displayed on the
display unit 220 via microprocessor 120 and microcomputer.
When the license code for the practice of medicine is found on the
corresponding ROM 110 but when the personal identification number is not
in agreement, this fact is displayed on the display unit 220, and the
processing is completed.
When even the license code for the practice medicine is not found on the
ROM 110, the license code for the practice of medicine and the personal
identification number input by the doctor are sent to the data management
center 400 where the computer 410 performs the collation with regard to
whether the data base contains data that are in agreement with the license
code for the practice of medicine and the personal identification number.
If the two are in agreement, a secret code which indicates the agreement
is sent to the IC card 100 via microcomputer 240 and the like. The IC card
100 takes out the data depending upon the permission level 116 of
information reference for non-registered doctors, and displays the data on
the display unit 220.
When the license code of for the practice of medicine or the personal
identification number of the doctor that is input is not in agreement,
this fact is displayed on the display unit 220, and the processing is
completed.
To avoid accidental agreement that might occur when the data are input many
times, it is allowable to provide such a countermeasure that repeated
access is not permitted in case an incorrect personal identification
number is input more than M times (M is a predetermined number). When
access is made to the data management center, furthermore, it can be
contrived to leave the license code for the practice of medicine, the data
and time, and the possessor of the card in the data base of the data
management center as a data log.
In the foregoing were described the cases where separate contents were
stored in the ROM 110 and EEPROM 140. The contents, how | | |
