U.S. patent application number 09/341676 was filed with the patent office on 2002-11-07 for non-contact ic card.
Invention is credited to CHIMURA, SHIGEMI, HIKITA, JUNICHI, IKEFUJI, YOSHIHIRO, TAGUCHI, HARUO.
Application Number | 20020162893 09/341676 |
Document ID | / |
Family ID | 11704704 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020162893 |
Kind Code |
A1 |
HIKITA, JUNICHI ; et
al. |
November 7, 2002 |
NON-CONTACT IC CARD
Abstract
A memory (1) in a non contact type IC card (100) includes a data
protection region (B2) storing data requiring security and an
region (B1) storing other data. A main control circuit (2)
generates data to be stored and designates a location for data
storage in the region (B1) or the data protection region (B2)
according to a content of the data. An address non selecting
circuit (4) selects whether the generated data is to be written
into the location in the data protection region (B2) designated by
the main control circuit (2) according to a state of a state
setting circuit (3).
Inventors: |
HIKITA, JUNICHI; (KYOTO,
JP) ; IKEFUJI, YOSHIHIRO; (KYOTO, JP) ;
CHIMURA, SHIGEMI; (KYOTO, JP) ; TAGUCHI, HARUO;
(KYOTO, JP) |
Correspondence
Address: |
GEORGE E. ORAM, JR.
ARENT FOX KINTNER PLOTKIN & KAHN, PLLC
1050 CONNECTICUT AVENIE, NW
SUITE 400
WASHINGTON
DC
20036-5339
US
|
Family ID: |
11704704 |
Appl. No.: |
09/341676 |
Filed: |
July 20, 1999 |
PCT Filed: |
January 9, 1998 |
PCT NO: |
PCT/JP98/00060 |
Current U.S.
Class: |
235/492 |
Current CPC
Class: |
G06Q 20/357 20130101;
G06Q 20/341 20130101; G06K 19/073 20130101; G07F 7/1008 20130101;
G06Q 20/105 20130101 |
Class at
Publication: |
235/492 |
International
Class: |
G06K 019/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 1997 |
JP |
9-8869 |
Claims
1. (Canceled)
2. (Canceled)
3. (Amended) A non contact type IC card performing a data
communication based on an externally applied radio wave signal,
comprising: receiving means (20) receiving said radio wave signal;
a rectifying circuit (21) connected to said receiving means (20);
first storing means (B2) storing said data requiring security;
second storing means (B1) storing data other than said data to be
stored in said first storing means (B2); control means (2)
generating said data based on the radio wave signal received at
said receiving means (20) and controlling for writing said data
into a location in one of said first storing means (B2) and said
second storing means (B1) according to a content of said generated
data; detection means (7) detecting a frequency of the radio wave
signal received by said receiving means (20); and selection means
(8) selecting whether said data is to be written into said location
in said first storing means (B2) designated by said control means
(2) based on a result of the detection by said detection means (7);
wherein when said receiving means (20) receives said radio wave
signal and the frequency of said radio wave signal is detected to
be a first frequency by said detection means (7), said data is
written into said location in said first storing means (B2)
designated by said control means (2), whereas when the frequency of
said radio wave signal is detected to be a second frequency other
than said first frequency by said detection means (7), said data is
not written into said location in said first storing means (B2)
designated by said control means (2).
4. (Canceled)
5. (Amended) A non contact type IC card responsive to externally
applied data for performing data communication, comprising: first
storing means (B2) storing said data requiring security; second
storing means (B1) storing data other than said data to be stored
in said first storing means (B2); control means (2) controlling for
writing said data into a location in one of said first storing
means (B2) and said second storing means (B1) according to a
content of said data; and data fixing means (9) receiving said data
to be written into said location in said first storing means (B2)
designated by said control means (2) and supplying a particular
data; wherein only said particular data supplied from said data
fixing means (9) is written into said location in said first
storing means (B2) designated by said control means (2), and
wherein a value of said particular data supplied from said data
fixing means (9) is a value determined by an initial state of said
first storing means (B2).
6. A non contact type IC card responsive to externally applied data
for performing data communication, comprising: first storing means
(B2) storing said data requiring security; second storing means
(B1) storing data other than said data to be stored in said first
storing means (B2); control means (2) controlling for writing said
data into a location in one of said first storing means (B2) and
said second storing means (B1) according to a content of said data;
selection means (11) selecting whether said data is to be written
into said location in said first storing means (B2) designated by
said control means (2); and state setting means (10) controlling
the selection by said selection means (4); wherein said data is
written into said location in said first storing means (32)
designated by said control means (2) when said state setting means
(10) is in a first state, whereas, said data is written into a
location other than said location in said first storing means (B2)
designated by said control means (2) when said state setting means
(10) is in a second state other than the first state.
7. (Canceled)
8. The non contact type IC card according to claim 6, wherein said
state setting means (3, 10) includes a fuse, said fuse is in an
electrically conductive state in said first state and said fuse is
in an electrically non conductive state in said second state.
9. (Canceled)
10. (Canceled)
11. (Amended) A non contact type IC card responsive to externally
applied data for performing data communication, comprising: first
storing means (16) storing said data requiring security; second
storing means (15) storing data other than said data to be stored
in said first storing means (16); control means (2) controlling for
writing said data into a location in one of said first storing
means (16) and said second storing means (15) according to a
content of said data; wherein said first storing means (16)
includes an EPROM, and wherein said second storing means (15)
includes an EEPROM.
12. (Amended) A non contact type IC card responsive to externally
applied data for performing data communication, comprising: first
storing means (16) storing said data requiring security; second
storing means (15) storing data other than said data to be stored
in said first storing means (16); control means (2) controlling for
writing said data into a location in one of said first storing
means (16) and said second storing means (15) according to a
content of said data; wherein said first storing means (16)
includes an EPROM, and wherein said second storing means (15)
includes a flash memory.
Description
TECHNICAL FIELD
[0001] The present invention relates to a non contact type IC card,
and more particularly to a non contact type IC card allowing the
protection of data stored in the card and the prevention of data
falsification.
BACKGROUND ART
[0002] A non contact type IC card performing data communication
with an interrogator installed outside has been used
conventionally. The examples include a ticket for ski lift, a
seasonal ticket for the transportation and a prepaid card.
[0003] FIG. 7 is a block diagram schematically showing a basic
structure of a conventional non contact type IC card 900.
Conventional non contact type IC card 900 shown herein, which is an
IC card performing data communication in a signal superposing
manner, supplies power and transmits/receives information using a
signal(s) having one or more frequencies received from the
interrogator not shown.
[0004] Conventional non contact type IC card 900 as shown in FIG. 7
is an example of non contact type IC cards utilizing a single
frequency and includes a tuning circuit 20, a rectifying circuit
21, an amplifying/demodulating circuit 22, a modulating/amplifying
circuit 23 and an SP/PS conversion circuit 24.
[0005] Tuning circuit 20 includes a coil L functioning as an
antenna and a capacitor C0. Rectifying circuit 21 rectifies a
signal received at tuning circuit 20, thereby generates and
supplies the power to each part of non contact type IC card
900.
[0006] Amplifying/demodulating circuit 22 amplifies and demodulates
data Q from an interrogator received at tuning circuit 20. A signal
output from amplifying/demodulating circuit 22 is SP-converted by
SP/PS conversion circuit 24 and then is output to a main control
circuit 2 described below.
[0007] With reference to FIG. 7, conventional non contact type IC
card 900 further includes main control circuit 2 and a memory
1.
[0008] Main control circuit 2 processes a signal output from SP/PS
conversion circuit 24. Main control circuit 2 generates data DA to
be stored in memory 1 described below and designates a location
(address) of memory 1 to which data DA is to be written.
[0009] Memory 1 includes normal data storage region B1 and data
protection region B2. Memory 1 receives data DA via a data line L2
as well as an address signal AD via an address line L1 indicating
an address (a location to which data is to be written) to which
data DA is to be written. Here, data stored in data protection
region B2 particularly requires security in order to guarantee a
normal data communication and whose rewriting is inhibited. An
example of such data is an ID number of an ID card holding the
personal information.
[0010] In addition, main control circuit 2 reads data from
designated region B1 or data protection region B2 of memory 1
according to the contents of data Q received from the interrogator
and generates a response data A based on the read data. Response
data A is PS-converted at SP/PS conversion circuit 24, processed at
modulating/amplifying circuit 23 and then transmitted to the
interrogator via coil L forming the antenna.
[0011] In conventional non contact type IC card 900, however, the
rewriting (falsification) of stored data in memory 1 can be easily
performed from a device other than the interrogator once the
protocol of the data communication with the interrogator is
decoded, therefore the security cannot be guaranteed.
[0012] Hence an object of the present invention is to provide a non
contact type IC card allowing the prevention of rewriting of a
storage region in which data requiring security is stored.
[0013] Another object of the present invention is to provide a
highly reliable non contact type IC card through the control of
rewriting of the storage region in which data requiring security is
stored.
DISCLOSURE OF THE INVENTION
[0014] A non contact type IC card according to the present
invention is responsive to externally applied data for performing
data communication, and includes: a first storing circuit storing
data requiring security; a second storing circuit storing data
other than the data to be stored in the first storing circuit; a
control circuit controlling for writing the data into a location in
one of the first storing circuit and the second storing circuit
according to a content of the data; a selection circuit selecting
whether the data is to be written into the location in the first
storing circuit designated by the control circuit; and a state
setting circuit controlling the selection by the selection circuit,
the data is written into the location in the first storing circuit
designated by the control circuit when the state setting circuit is
in a first state, whereas, the data is inhibited from being written
into the first storing circuit designated by the control circuit
when the state setting circuit is in a second state other than the
first state.
[0015] In another aspect of the present invention, a non contact
type IC card is responsive to externally applied data for
performing data communication, and includes: a first storing
circuit storing the data requiring security; a second storing
circuit storing data other than the data to be stored in the first
storing circuit; a control circuit controlling for writing the data
into a location in one of the first storing circuit and the second
storing circuit according to a content of the data; a detection
circuit receiving a control signal from the control circuit and
giving instruction for controlling a state of the first storing
circuit; and a selection circuit receiving the instruction of the
detection circuit and selecting whether the data is to be written
into the location of the first storing circuit designated by the
control circuit; and the control signal output from the control
circuit indicates whether the first storing circuit is in a data
rewriting permitted state or a data rewriting inhibited state; and
the data is written into the location in the first storing circuit
designated by the control circuit when the detection circuit
detects that the first storing circuit is in the data rewriting
permitted state, whereas the data is not written into the location
in the first storing circuit designated by the control circuit when
the detection circuit detects that the first storing circuit is in
the data rewriting inhibited state.
[0016] In still another aspect of the present invention, a non
contact type IC card performs a data communication based on an
externally applied radio wave signal, and includes: a receiving
circuit receiving the radio wave signal; a first storing circuit
storing the data requiring security; a second storing circuit
storing data other than the data to be stored in the first storing
circuit; a control circuit generating the data based on the radio
wave signal received at the receiving circuit and controlling for
writing the data into a location in one of the first storing
circuit and the second storing circuit according to a content of
the generated data; a detection circuit detecting a frequency of
the radio wave signal received by the receiving circuit; and a
selection circuit selecting whether the data is to be written into
the location in the first storing circuit designated by the control
circuit based on a result of the detection by the detection
circuit; and wherein the data is written into the location in the
first storing circuit designated by the control circuit, when the
receiving circuit receives the radio wave signal and the frequency
of the radio wave signal is detected to be a first frequency by the
detection circuit, whereas the data is not written into the
location in the first storing circuit designated by the control
circuit when the frequency of the radio wave signal is detected to
be a second frequency other than the first frequency by the
detection circuit.
[0017] In still another aspect of the present invention, a non
contact type IC card is responsive to externally applied data for
performing data communication, and includes: a first storing
circuit storing the data requiring security; a second storing
circuit storing data other than the data to be stored in the first
storing circuit; a control circuit controlling for writing the data
into a location in one of the first storing circuit and the second
storing circuit according to a content of the data; and a data
fixing circuit receiving the data to be written into the location
in the first storing circuit designated by the control circuit and
supplying a particular data; and wherein a value of the
predetermined data supplied from the data fixing circuit is a value
determined by an initial state of the first storing circuit, and
wherein only the particular data supplied from the data fixing
circuit is written into the location in the first storing circuit
designated by the control circuit.
[0018] In still another aspect of the present invention, a non
contact type IC card is responsive to externally applied data for
performing data communication, and includes: a first storing
circuit storing said data requiring security; a second storing
circuit storing data other than the data to be stored in the first
storing circuit; a control circuit controlling for writing the data
into a location in one of the first storing circuit and the second
storing circuit according to a content of the data; a selection
circuit selecting whether the data is to be written into the
location in the first storing circuit designated by the control
circuit; and a state setting circuit controlling the selection by
the selection circuit; and wherein the data is written into the
location in the first storing circuit designated by the control
circuit when the state setting circuit is in a first state,
whereas, the data is written into a location other than the
location in the first storing circuit designated by the control
circuit when the state setting circuit is in a second state other
than the first state.
[0019] In still another aspect of the present invention, a non
contact type IC card is responsive to externally applied data for
performing data communication, and includes: a first storing
circuit storing the data requiring security; a second storing
circuit storing data other than the data to be stored in the first
storing circuit; and a control circuit controlling for writing the
data into a location in one of the first storing circuit and the
second storing circuit according to a content of the data; and
wherein the first storing circuit allows rewriting of a
predetermined times.
[0020] Therefore a main advantage of the present invention lies in
the prevention of falsification of storage contents through the
control of rewriting of data stored in a storage portion storing
data requiring security.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a structure of a main portion of a non contact
type IC card 100 according to a first embodiment of the present
invention.
[0022] FIG. 2 shows a structure of a main portion of a non contact
type IC card 200 according to a second embodiment of the present
invention.
[0023] FIG. 3 shows a structure of a main portion of a non contact
type IC card 300 according to a third embodiment of the present
invention.
[0024] FIG. 4 shows a structure of a main portion of a non contact
type IC card 400 according to a fourth embodiment of the present
invention.
[0025] FIG. 5 shows a structure of a main portion of a non contact
type IC card 500 according to a fifth embodiment of the present
invention.
[0026] FIG. 6 shows a structure of a main portion of a non contact
type IC card 600 according to a sixth embodiment of the present
invention.
[0027] FIG. 7 is a diagram schematically showing a structure of a
conventional non contact type IC card 900.
BEST MODES FOR CARRYING OUT THE INVENTION
[0028] First Embodiment
[0029] The first embodiment of the present invention allows the
prevention of rewriting of data previously stored in a data
protection region by controlling an address to which data is to be
written, at data writing for the data protection region of a memory
in a non contact type IC card.
[0030] FIG. 1 shows a structure of a main portion of a non contact
type IC card 100 according to the first embodiment of the present
invention. Components similar to those in conventional non contact
type IC card 900 shown in FIG. 7 are denoted by the same reference
numbers and same reference characters and the description thereof
will not be repeated. Here, data transmission of the non contact
type IC card adopting the present invention may be either in a
signal superposing method or in a signal separating method.
[0031] Non contact type IC card 100 shown in FIG. 1 differs from
conventional non contact type IC card 900 in that card 100 includes
a state setting circuit 3 and an address non selecting circuit 4
controlling a write address designated at data writing for data
protection region B2 of memory 1.
[0032] With reference to FIG. 1, the structure of non contact type
IC card 100 according to the first embodiment of the present
invention will be described.
[0033] Address non selecting circuit 4 receives a write enable
signal RE supplied from main control circuit 2 and an address
signal AD from an address line L1 as inputs. Here, address signal
AD designates a location in data protection region B2 to which data
DT on a data line L2 is to be written, and write enable signal RE
designates a data writing operation to data protection region B2.
Address non selecting circuit 4 being controlled by state setting
circuit 3 described below outputs an address selecting signal AC
according to address signal AD.
[0034] State setting circuit 3 controls address non selecting
circuit 4 described above.
[0035] Address selecting signal AC output from address non
selecting circuit 4 changes its state based on a state (active
state/inactive state) of state setting circuit 3. Specifically,
when state setting circuit 3 is in an active state, an output
address selecting signal AC selects a location designated by
address AD as a location to which data is to be written, whereas
when state setting circuit 3 is in an inactive state, an output
address selecting signal AC inhibits the writing to the location
designated by address signal AD (non select state).
[0036] Data DT will be written into a location in data protection
region B2 corresponding to and based on address selecting signal AC
output from address non selecting circuit 4.
[0037] Next, an operation of non contact type IC card 100 according
to the first embodiment of the present invention will be
described.
[0038] First, when state setting circuit 3 is in an active state,
address non selecting circuit 4 having received write enable signal
RE and address signal AD outputs address selecting signal AC
selecting a location designated by the address signal AD. In this
case data DT will be written into the corresponding location in
data protection region B2.
[0039] On the other hand, when stage setting circuit 3 is in an
inactive state, address non selecting circuit 4 having received
write enable signal RE and address signal AD outputs address
selecting signal AC turning the location designated by the address
signal AD to a non select state. In this case data DT is not
written into data protection region B2.
[0040] One example of such state setting circuit 3 uses a fuse. For
example, when a fuse is used, any numbers of data can be written
into data protection region B2 before the fuse blow, however, after
the fuse blow, data in data protection region B2 can not be
rewritten. The methods of blowing the fuse includes high voltage
application, laser cutting, induction heating or the like.
[0041] In other words, by controlling the state of state setting
circuit 3, non contact type IC card 100 can inhibit the access to
data protection region B2 for data rewriting after the data
requiring security is stored in data protection region B2 (for
simplicity this state is referred to as protection data storage
state).
[0042] Thus in non contact type IC card 100, as the address
selection for the data protection region can be controlled at the
data writing operation, the falsification of data previously stored
in the data protection region can be prevented.
[0043] Second Embodiment
[0044] Similar to the first embodiment of the present invention,
the non contact type IC card according to the second embodiment of
the present invention allows the prevention of rewriting of data
stored in the data protection region by controlling an address to
which the data is to be written at the time of data writing to the
data protection region in the memory.
[0045] FIG. 2 shows a structure of a main portion of a non contact
type IC card 200 according to the second embodiment of the present
invention and components similar to those in non contact type IC
card 100 shown in FIG. 1 are denoted by the same reference numbers
and same reference characters and the description thereof will not
be repeated.
[0046] Non contact type IC card 200 shown in FIG. 2 is different
from conventional non contact type IC card 900 in that it includes
a command detection circuit 5 and an address non selecting circuit
6 controlling a designated address to which data is to be written
at the time of data writing to the data protection region of the
memory, and controls these circuits by a command output from a main
control circuit 12.
[0047] With reference to FIG. 2, the structure of non contact type
IC card 200 according to the second embodiment of the present
invention will now be described.
[0048] Address non selecting circuit 6 receives an address signal
AD via an address line L1 as an input. Here, address signal AD
indicates a location in data protection region B2 to which data DT
on a data line L2 is to be written. Address non selecting circuit 6
controlled by command detection circuit 5 described below outputs
address selecting signal AC according to the address signal AD.
[0049] Command detection circuit 5 receives an address control
command COM output from main control circuit 12 and controls
address non selecting circuit 6. Here, address control command COM
is a command permitting or inhibiting a data writing operation to
data protection region B2 based on the address signal AD.
[0050] Address selecting signal AC output from address non
selecting circuit 6 changes its state according to a state of
command detection circuit 5. Specifically, when command detection
circuit 5 detects a writing permitted state of a data protection
region B2, an address selecting signal AC selecting a location
designated by address AD as a location to which data is to be
written is output. On the other hand, if data protection region B2
is detected to be in a writing inhibited state, address selecting
signal AC turning a location designated by address signal AD to a
non select state is output.
[0051] Based on the address selecting signal AC supplied from
address non selecting circuit 6, data DT is written into a
corresponding location in data protection region B2.
[0052] Next an operation of non contact type IC card 200 according
to the second embodiment of the present invention will be
described.
[0053] When an address control command COM permitting the data
writing is supplied from main control circuit 12, and is detected
by command detection circuit 5, address non selecting circuit 6
outputs an address selecting signal AC selecting a location
designated by the address signal AD. In this case data DT is
written into a corresponding location in data protection region
B2.
[0054] On the other hand, when an address control command COM
inhibiting the data writing is supplied from main control circuit
12, and is detected by command detection circuit 5, address non
selecting circuit 6 outputs an address selecting signal AC turning
the location designated by the address signal AD to a non select
state. In this case data DT is not written into data protection
region B2.
[0055] Thus, non contact type IC card 200 allows the adjustment of
storage of data requiring security in data protection region B2
(turning data protection region B2 to the protection data storage
state) and inhibiting the access to data protection region B2 for
the data rewriting, through the control of command detection
circuit 5 based on a command output from main control circuit
12.
[0056] As non contact type IC card 200 allows the control of
selection of address of the data protection region at the data
writing operation, the falsification of data previously stored in
the data protection region can be prevented.
[0057] Third Embodiment
[0058] The third embodiment of the present invention allows the
prevention of rewriting of data once stored in the data protection
region in the non contact type IC card through the access control
for the data protection region according to the frequency for data
communication.
[0059] FIG. 3 shows a structure of a main portion of a non contact
type IC card 300 according to the third embodiment of the present
invention, wherein components similar to those in non contact type
IC card 100 shown in FIG. 1 are denoted by the same reference
numbers and same reference characters, and the description thereof
will not be repeated.
[0060] Non contact type IC card 300 shown in FIG. 3 is different
from conventional non contact type IC card 900 in that it includes
a frequency detection circuit 7 and an address non selecting
circuit 8.
[0061] With reference to FIG. 3, the structure of non contact type
IC card 300 according to the third embodiment of the present
invention will now be described.
[0062] Frequency detection circuit 7 detects a frequency of a radio
wave received by tuning circuit 20 and includes a band pass filter
and a switching circuit inside not shown. When a carrier frequency
of a received radio wave is a predetermined frequency F1, frequency
detection circuit 7 detects the reception of an intended radio
wave.
[0063] Address non selecting circuit 8 receives address signal AD
via address line L1 and a write enable signal RE from main control
circuit 2 as inputs. Here, address signal AD designates a location
in data protection region B2 to which data DT on data line L2 is to
be written.
[0064] Address non selecting circuit 8 controlled by frequency
detection circuit 7 outputs address selecting signal AC according
to address signal AD. More specifically, when frequency detection
circuit 7 detects the reception of an intended radio wave (with
predetermined frequency F1), an address selecting signal AC
selecting a location designated by address signal AD as a location
to which data is to be written is output, and otherwise (when
received radio wave has a frequency other than the predetermined
frequency F1), an address selecting signal AC turning the location
designated by the address signal AD to a non select state is
output.
[0065] Based on the address selecting signal AC, data DT is written
into the corresponding location in data protection region B2.
[0066] With reference to FIG. 3, an operation of non contact type
IC card 300 will be described specifically.
[0067] As described above, when a radio wave with a carrier
frequency F1 is received, address non selecting circuit 8 outputs
an address selecting signal AC selecting a location designated by
address signal AD. In this case data DT is written into the
corresponding location in data protection region B2.
[0068] On the other hand, when a radio wave with a carrier
frequency being an original frequency F0 different from F1 is
received, address non selecting circuit 8 outputs an address
selecting signal AC turning the location designated by address
signal AD to a non select state. In this case data DT is not
written into data protection region B2.
[0069] In other words, non contact type IC card 300 allows the
adjustment of the storage of data requiring security in data
protection region B2 (turning data protection region B2 to the
protection data storage state) and inhibiting the access to data
protection region B2 for the data rewriting, through the use of
different frequencies.
[0070] Thus, as a non contact type IC card 300 allows the access
control for the data protection region according to the frequency
of radio wave for the data communication, the falsification of data
previously stored in the data protection region can be
prevented.
[0071] Fourth Embodiment
[0072] The fourth embodiment of the present invention allows the
prevention of data falsification, which is the object of the
present invention, in the non contact type IC card by controlling
the data to be written at the data writing to the data protection
region in the memory.
[0073] FIG. 4 shows a structure of a main portion of a non contact
type IC card 400 according to the fourth embodiment of the present
invention, wherein components similar to those in non contact type
IC card 100 shown in FIG. 1 are denoted by the same reference
numbers and same reference characters, and the description thereof
will not be repeated.
[0074] Non contact type IC card 400 shown in FIG. 4 is different
from conventional non contact type IC card 900 in that it includes
an input data fixing circuit 9 controlling data to be written into
data protection region B2 of memory 1.
[0075] With reference to FIG. 4, the structure of non contact type
IC card 400 according to the fourth embodiment of the present
invention will be described.
[0076] Input data fixing circuit 9 fixes a state of each location
in data protection region B2 of memory 1.
[0077] Input data fixing circuit 9 receives data DT1 via a data
line L2 as an input, converts data DT1 and outputs data DT2. Data
DT2 is data to be written into data protection region B2.
[0078] A value of data DT2 output from input data fixing circuit 9
is determined based on an initial state of data protection region
B2. When states of all bits in data protection region B2 are "1",
for example, data DT2 always takes a value of the reverse polarity,
in this case "0". Hence, when main control circuit 2 outputs data
DT1 corresponding to the value "1", the data writing to data
protection region B2 will not be performed.
[0079] With reference to FIG. 4, an operation of non contact type
IC card 400 will be described specifically.
[0080] Assume that an initial state of each bit in data protection
region B2 in memory 1 is set to "1" (the state of bit to "1111").
In this case, input data fixing circuit 9 receiving data DT1
outputs only the data DT2 of "0" for each bit.
[0081] First, data requiring security will be written into data
protection region B2 (protection data storage state). Here, assume
that the protection data storage state is "1100". As described
above, data DT2 output from input data fixing circuit 9 takes the
value "0". Therefore, the bit once takes the state "0" cannot be
returned to the state "1". As a result, thereafter, the state of
data protection region B2 ("1100") cannot be rewritten to "1101",
for example.
[0082] Thus, data protection region B2 of non contact type IC card
400 functions as an OTP ROM (a non volatile memory allowing only
one rewriting) and once data is stored in the data protection
region, trial of the data rewriting is highly likely to result in a
failure of an intended data setting.
[0083] Thus, as described above, as non contact type IC card 400
allows the control of data to be written into the data protection
region at the data writing operation, the rewriting of data once
stored in the data protection region can be prevented.
[0084] Fifth Embodiment
[0085] The fifth embodiment of the present invention allows the
prevention of data falsification, which is the object of the
present invention, in the non contact type IC card, by controlling
an address to which data is to be written at the data writing
operation to the data protection region of the memory.
[0086] FIG. 5 shows a structure of a main portion of a non contact
type IC card 500 according to the fifth embodiment of the present
invention, wherein components similar to those in non contact type
IC card 100 shown in FIG. 1 are denoted by the same reference
numbers and same reference characters, and the description thereof
will not be repeated.
[0087] Non contact type IC card 500 shown in FIG. 5, is different
from conventional non contact type IC card 900 in that it includes
a state setting circuit 10 and an address non selecting circuit 11
controlling a designated address to which data is to be written at
the writing to data protection region B2 of memory 1.
[0088] With reference to FIG. 5, the structure of non contact type
IC card 500 according to the fifth embodiment of the present
invention will be described.
[0089] Address non selecting circuit 11 receives a write enable
signal RE output from main control circuit 2 and address signal AD
via address line L1 as inputs. Here, address signal AD designates a
location in data protection region B2 to which data DT on data line
L2 is to be written. Address non selecting circuit 11 controlled by
state setting circuit 10 described below, outputs address selecting
signal AC according to address signal AD.
[0090] State setting circuit 10 controls address non selecting
circuit 11 described above.
[0091] Address selecting signal AC output from address non
selecting circuit 11 changes its state according to a state (active
state/inactive state) of state setting circuit 10. More
specifically, when state setting circuit 10 is in an active state,
address selecting signal AC selecting a location designated by
address signal AD as a location to which data is to be written is
output, and when state setting circuit 10 is in an inactive state,
address selecting signal AC selecting a location other than the
location designated by address signal AD (or selecting neither of
the location) is output.
[0092] Based on the address selecting signal AC output from address
non selecting circuit 11, data DT is written into the corresponding
location in data protection region B2.
[0093] Next, an operation of non contact type IC card 500 according
to the fifth embodiment of the present invention will be
described.
[0094] First, when state setting circuit 10 is in an active state,
address non selecting circuit 11 having received write enable
signal RE and address signal AD outputs an address selecting signal
AC selecting a location designated by address signal AD. In this
case, data DT is written into the corresponding location in data
protection region B2.
[0095] On the other hand, when state setting circuit 10 is in an
inactive state, address non selecting circuit 11 having received
write enable signal RE and address signal AD outputs an address
selecting signal AC selecting a location other than the location
designated by address signal AD (or selecting neither of the
locations). In this case, data DT is not written into the intended
location of data protection region B2.
[0096] As described above, an example of such state setting circuit
10 includes a fuse.
[0097] Thus even if the rewriting operation occurs, non contact
type IC card 500 can inhibit the rewriting of the intended data,
after the data requiring security is stored in data protection
region B2 (protection data storage state), by controlling the state
of state setting circuit 10.
[0098] Thus, as non contact type IC card 500 allows the control of
address selection in the data protection region at the data writing
operation, rewriting and use of the data previously stored in the
data protection region can be prevented.
[0099] Sixth Embodiment
[0100] According to the sixth embodiment of the present invention,
a non contact type IC card includes an OTP ROM (an non volatile
memory allowing only one rewriting) as a storage medium
corresponding to the data protection region.
[0101] FIG. 6 shows a structure of a main portion of a non contact
type IC card 600 according to the sixth embodiment of the present
invention, wherein components similar to those in non contact type
IC card 100 shown in FIG. 1 are denoted by the same reference
characters and the description thereof will not be repeated.
[0102] Non contact type IC card 600 shown in FIG. 6 is different
from conventional non contact type IC card 900 in that it includes
a memory 15 and a memory 16 instead of memory 1.
[0103] With reference to FIG. 6, the structure of non contact type
IC card 600 according to the sixth embodiment of the present
invention will be described.
[0104] Memory 15 is a storage medium storing rewritable data
whereas memory 16 is a storage medium storing data requiring the
security.
[0105] Specifically, memory 15 includes a non volatile memory
allowing rewriting as required such as an EEPROM and a flash
memory, whereas memory 16 includes a memory allowing only one
rewriting such as an EPROM.
[0106] Next, an operation of non contact type IC card 600 according
to the sixth embodiment of the present invention will be described.
For simplicity, in the description, memory 16 is assumed to be an
EPROM.
[0107] Data to be held that is output from main control circuit 2
is stored in memory 15 or memory 16.
[0108] In this case, as memory 16 is an EPROM, once electric charge
is stored in a memory cell not shown, the electric charge cannot be
discharged until it is exposed to ultraviolet light. Therefore,
assuming that the state of a memory cell with electric charge
stored is called state 1 and the discharged state of the memory
cell is called state 0, after the encapsulation of IC card 600, in
memory 16, a memory cell in the state 0 can be charged to be the
state 1, however, a memory cell in the state 1 cannot be rewritten
to be the state 0.
[0109] Therefore, it is highly unlikely that the trial of rewriting
of data once stored in memory 16 achieves the intended data
rewriting.
[0110] Thus, with the use of an OTPROM as a medium for storing data
to be protected, non contact type IC card 600 allows the
suppression of data falsification to an extremely low level.
[0111] As can be seen from the foregoing, according to the present
invention, the rewriting of storage region in which data requiring
the security is stored can be prevented through the control of data
rewriting.
[0112] In addition, according to the present invention, as the
rewriting can be controlled with respect to the storage region in
which data requiring the security is stored, the reliability of the
non contact type IC card can be dramatically improved.
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