Electrical computers and digital processing systems: support – Multiple computer communication using cryptography – Particular communication authentication technique
Reexamination Certificate
1999-07-26
2004-05-25
Hua, Ly V. (Department: 2135)
Electrical computers and digital processing systems: support
Multiple computer communication using cryptography
Particular communication authentication technique
C713S159000, C713S187000, C713S152000, C235S375000, C235S492000, C235S454000, C703S023000
Reexamination Certificate
active
06742117
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an IC card and a method of using an IC card. Particularly, the present invention relates to an IC card and an IC card usage method improved in security.
BACKGROUND ART
A communication system using a non-contact type IC card is employed in the automatic examination for lifts in skiing grounds and railroads, automatic sorting of parcels, and the like. An example of a conventional non-contact type IC card is shown in FIG.
16
. An IC card
2
shown in
FIG. 16
is a one-coil type IC card, including a coil
4
functioning as an antenna, capacitors C
1
and C
2
, and an IC chip
8
.
Capacitors C
1
, C
2
and IC chip
8
are mounted on a film-like synthetic resin substrate. The substrate mounted with capacitors C
1
, C
2
and IC chip
8
is referred to as a tab (tape automated bonding)
10
.
FIG. 17A
is a sectional view of IC card
2
taken along S
1
—S
1
of
FIG. 16. A
core member
12
formed of synthetic resin is sandwiched by a pair of surface layer members
14
and
16
. Tab
10
mounted with capacitors C
1
, C
2
and IC chip
8
is fixed at surface layer member
14
exposed within a cavity
18
provided in core member
12
. The junction portion of tab
10
and IC chip
8
is covered with an encapsulant
9
such as of epoxy resin.
Coil
4
is located between surface layer member
14
and core member
12
. Coil
4
and tab
10
are connected by a wire
20
.
FIG. 17B
shows a circuit diagram of IC card
2
. IC card
2
receives an electromagnetic wave sent from a reader/writer (an interrogator not shown) by a resonant circuit
22
formed by coil
4
and capacitor C
1
as the power source. Capacitor C
2
is the capacitor for smoothing power.
The information sent in an overlapping manner with the electromagnetic wave is decoded by a control unit (not shown) provided in IC chip
8
, whereby the contents of a nonvolatile memory (not shown) provided in IC chip
8
is rewritten, and a response is sent back to the reader/writer. This response is effected by altering the impedance of resonant circuit
22
. The reader/writer identifies the contents of the response by detecting change in impedance (impedance reflectance) of its own resonant circuit (not shown) corresponding to the impedance change of resonant circuit
22
of IC card
2
.
By using such an IC card
2
, data can be transmitted/received without requiring a power source in the card and in an non-contact manner.
A communication system using the above-described conventional IC card has problems set forth in the following. In a communication system using a conventional IC card, security is sought by encrypting the communication data between the reader/writer and the IC card. However, the data can be decoded and rewritten if the encryption is decoded. It is therefore difficult to ensure the security of the system by means of only the encryption.
There is an approach of preventing improper reproduction of an IC card of no further use by completely disabling data rewriting of the IC card of no further use. However, this will prevent recycling of the IC card, resulting in increase in the cost of IC cards.
An object of the present invention is to provide an IC card of high security and low cost, and a method of using an IC card, solving the above problems.
DISCLOSURE OF THE INVENTION
To achieve the above object, an IC card according to an aspect of the present invention includes a data communication unit for data communication with an interrogator, a data storage unit storing data, and an access control unit controlling access of the data storage unit according to the data obtained from the data communication unit. The access control unit includes a data initialization unit initializing the data storage unit according to a predetermined data initialization instruction obtained from the data communication unit, and a particular data write control unit providing control to allow predetermined particular data of card application to be written only once into the data storage unit that is initialized by the data initialization unit.
The IC card of the present invention is characterized in that the data storage unit is initialized according to a predetermined data initialization instruction to allow predetermined particular data of card application to be written only once onto the initialized data storage unit.
Therefore, the particular data once written into the data storage unit cannot be rewritten unless the data storage unit is initialized. Furthermore, the data storage unit can be initialized by only the person who knows the predetermined data initialization instruction. Therefore, unauthorized rewriting of particular data can be substantially prevented by distinguishing the person who can write in the particular data and the person who can initialize the data storage unit. Thus, the security of the card can be improved.
Since the card can be initialized in addition to prevent improper rewriting, recycling of the card is allowed. Therefore, the cost of the card can be reduced.
Preferably, the IC card further includes a private key storage unit to store a private key to access the particular data stored in the data storage unit. The access control unit further includes a particular data read out control unit to provide control to allow particular data to be read out only when the private key is input.
The IC card of the present invention is characterized by including a private key storage unit storing a private key to access particular data stored in the data storage unit to allow the particular data to be read out only when the private key is input.
The particular data can be read out only by the person who knows the private key for that particular data. By keeping this private key confidential, leakage of the particular data can be prevented. In other words, the security of the card is further improved.
Further preferably, a particular data write control unit provides control to allow particular data to be written only once into the data storage unit that is initialized by the data initialization unit only when the private key is input.
The IC card of the present invention is characterized in that the particular data can be written only once into the initialized data storage unit only when the private key is input.
Particular data can be written only by the person who has knowledge of the private key for the particular data. Therefore, writing of particular data other than an authorized person can be prevented by keeping the private key confidential.
Further preferably, the access control unit further includes a private key initialization unit initializing the private key storage unit according to a predetermined private key initialization instruction obtained from the data communication unit, and a private key write control unit providing control to allow the private key to be written only once into the private key storage unit that is initialized by the private key initialization unit.
The IC card of the present invention is characterized in that the private key can be written only once into the initialized private key storage unit according to a predetermined private key initialization instruction.
Therefore, the private key once written into the private key storage unit cannot be rewritten unless the private key storage unit is initialized. Only the person who has knowledge of the predetermined private key initialization instruction can initialize the private key storage unit. Unauthorized rewriting of the private key can be substantially prevented by distinguishing the person who can write in a private key and the person who can initialize the private key storage unit. Thus, the security of the card is further improved.
Since the card can be initialized in addition to preventing improper rewriting, recycling of the card is allowed. Therefore, the cost of the card can be further reduced.
Further preferably, the IC card is configured to allow the private key to be written only once into the private key storage unit.
According to the present invention, a private key once written can
Hikita Junichi
Ikefuji Yoshihiro
Komuro Toyokazu
Arent Fox Kintner Plotkin & Kahn
Hua Ly V.
Rohm & Co., Ltd.
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