JPH07105335A - Information card - Google Patents

Abstract

PURPOSE:To provide the inexpensive information card used again while rejecting illegal use by an unauthorized party. CONSTITUTION:The card is provided with a rewritable nonvolatile semiconductor memory that stores the number of times or the like and to rewrite the data. When the data are rewritten, whether or not the user is a legal user is judged through key collation. The rewrite of data is limited in one direction from '1' to '0' by a delete control logic 210 and rewrite is initialized from '0' to '1' for a predetermined number of times. The initializing available frequency is stored in a fuse memory 200 or the like. Data in the memory 200 are updated in the case of initializing to limit the initializing for a predetermined frequencies or over.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information card such as a prepaid card, and more particularly to a prepaid card which can be reused by using a rewritable nonvolatile semiconductor memory.

[0002]

2. Description of the Related Art Magnetic cards have been the mainstream of prepaid prepaid cards. A magnetic card is a plastic card in which a magnetic material is applied to a part of one side, and information is magnetically recorded on the magnetic material. However, although the magnetic card has a low manufacturing cost, it has a drawback that the cost for counterfeiting is low and the magnetic card is easily forged. Therefore, an IC memory card is used as a prepaid card because it has a high forgery cost and is therefore difficult to forge. In this IC memory card, a memory portion (memory cell) for recording information is composed of a non-rewritable fuse memory, and the number of times of use is counted and recorded by cutting the fuse.

[0003]

However, when such an IC memory card is used as a prepaid card, the card cannot be reused and is therefore disposable, which is not preferable in terms of resource protection and environmental pollution. In addition, since it is not reused, the manufacturing cost of the prepaid card itself is high.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a new type of information card which can be reused and which prevents unauthorized use.

[0005]

According to a first aspect of the present invention, there is provided a user memory formed of a non-volatile semiconductor memory capable of rewriting data stored in a plurality of memory cells,
When the rewriting means for rewriting the data in the plurality of memory cells of the user memory, the key storing means for storing the key indicating the authorized user, and the input key matches the key stored in the key storing means An information card including: a collating unit that allows rewriting of data by the rewriting unit.

According to a second aspect of the present invention, the rewriting means is an initialization means that enables initialization of the data in the user memory, and an initialization control means that limits the number of times initialization is possible by the initialization means. In addition to the above, the collating means is an information card which permits initialization by the initializing means when the input key matches the key stored in the key storing means.

The invention described in claim 3 is the information card according to claim 2, wherein the key storage means and the initialization control means are constituted by a wired logic.

[0008]

In the information card according to claims 1 to 3,
At the beginning of issuance, the user memory records service units (such as telephone frequency) corresponding to the prepaid fee, for example. When a service or the like is received using this information card, the data of the service unit corresponding to the received service is erased from the user memory. That is, the data in the memory cell of the user memory is rewritten, for example, from "1" to "0". Further, for example, when all the data recorded in advance is rewritten (erased), this user memory can be initialized. Initialization is to store "1" again for all memory cells. This initialization makes this user memory reusable.

In the above cases, this information card prevents unauthorized use by unauthorized persons. That is, when the information card is used, a key input is required, and only when the input key matches the stored key, rewriting of data, for example, initialization of data in the user memory is permitted. Further, even a legitimate authority limits the number of times of initialization to eliminate the cause of unauthorized use. In particular, if a circuit is formed by using a wired logic for a part of the circuit and the number of initializations is controlled, it is possible to completely eliminate the possibility of improper use of initialization and use without limitation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 4 are for explaining a prepaid card as an information card according to an embodiment. This prepaid card is constructed by mounting an IC chip on a plastic card substrate. As shown in FIG. 1, the IC chip includes a memory array (user memory) 100 including, for example, a flash memory, and a wired array for controlling writing, erasing, and the like for a plurality of memory cells of the memory array 100. The logic etc. are installed.

The clock generator 10 generates an internal clock fc based on a synchronizing clock input from the outside. The command decoder 20 takes in an external command (FIG. 4 shows a block structure of the command) using the internal clock fc. The command decoder 20 sends an erase (erase) signal, a read / write (read / write) signal, and a verify (verify) signal to the erase control logic 210, the read / write logic 110, and the collation control logic 150 according to this command. Are output respectively. Command decoder 20
The data is read, written, or erased from or to each memory cell of the memory array 100 in accordance with an output signal from the memory array 100. Further, the input key is collated with the key indicating the authorized user stored in the key storage memory 160 by the verify signal.

The memory array 100 is used as a data memory for a user, and is composed of, for example, a flash type non-volatile memory, and a predetermined number of memory cells are set to an initial value "1" ( The number of memory cells set to "1" corresponds to the number of telephone calls that can be used with this card, for example). The access to the memory array 100 is performed via the address decoder 120 that performs address control and the data register 130 that performs data control. Reference numeral 140 is an output buffer for outputting data, and the output buffer 140 is connected to the memory array 100 via the data register 130. For example, the data output to a card reader (telephone etc.) is temporarily buffered.

The read / write control logic 110 controls read / write of data for each memory cell of the memory array 100 according to an external command. That is, the read / write control logic 110 is a circuit that performs timing control of data read / write and Vpp control.

Hereinafter, the erase control logic 2 will be described with reference to FIG.
10 will be described. The erase control logic 210 is composed of (1) to (3) and controls the number of erasable times (initialization number) of the memory array 100.

The timing control circuit 212 is composed of a binary up counter, a comparator and the like.
The binary up counter counts the internal clock fc generated by the CR timer or the clock generator 10. The comparator compares the counter value of the binary up counter with a predetermined value and generates a predetermined timing. In addition, the signal line C0 of the timing control circuit 212,
OE and WE terminals of the EPROM 200 are connected to C1. The signal on the signal line C2 is EPROM
This is a control signal when the data of 200 is loaded into the shift register 211. Similarly, the output from the signal line C3 is a control signal for right-shifting the contents of the shift register 211 and doubling the stored value. The signals on the signal lines C2 and C3 are valid at the falling edge (see FIG. 3).

The shift register 211 is an EPROM 2
00 (which may be a fuse memory). The shift register 211 doubles the output value of the EPROM 200. The shift register 211 has an (n + 1) -bit configuration, and the EPROM 200 has an n-bit configuration.

This EPROM 200 is initialized (erased).
It functions as a counter that indicates the number of times, and the number of times all data in the memory array 100 can be erased (the number of times that initialization is possible)
Is stored. The initial value of each memory cell of the memory array 100 is “1”. The EPROM 200 is constructed so that it cannot be directly accessed from the outside.

The OR gate 213 is the EPROM 200.
Connected to all data bits of. That is, EPR
The input / output signal lines D1 to Dn of the OM200 are used as inputs for this O
It is connected to the R gate 213, and its output is input to the AND gate 214. Inputs / outputs D1 to Dn of the shift register 211 are added to outputs D1 to Dn of the EPROM 200, respectively.

The AND gate 214 is the OR gate 21.
3 and the output C0 from the timing control circuit 212
And the rewriting (erasing) permission signal EN from the collation control logic 150 are input. The output signal of the AND gate 214 is the control signal ERS input to the address decoder 120, and the control signal ERS =
In the case of "L", erasing of data in the memory array 100 is prohibited, and in the case of ERS = "H", erasing of data is permitted and instructed.

The collation control logic circuit 150 collates the key indicating the legitimate user with the input key according to the verify command, and if they match, the rewrite (erase) permission signal EN is output and the erase control logic circuit 210 ( This is a configuration for outputting to the AND gate 214). The key indicating the authorized user is stored in a part (key storage means) 160 of the memory of the chip. Therefore, the data (data of the memory array 100, data of the number of times of initialization of the EPROM 200) can be rewritten only when the rewrite permission signal EN is input.

Rewriting of data with a prepaid card will be described below. In this prepaid card, when an erasing command (initializing command of the memory array 100) is received from the outside (card writer, etc.), it is checked whether erasing is possible. If so, do not execute. Also, when erasing (initialization) is completed,
Updates the data indicating the number of erasable times (decrements in bit units). Note that the memory array 100 is initialized by rewriting all the specified number of memory cells to the initial value "1". That is, if the telephone card has a frequency of 50 degrees, it is possible to use the frequency of 50 degrees again by the initialization. In the rewriting check, the user inputs a key from the outside and collates the key with the stored key. If the keys match as a result of verification, initialization is possible.

Specifically, first, the command decoder 20 decodes the instruction code (FIG. 4). The command ($ 04, $ 08) requesting key verification waits for key input. If there is a key input, the input key is collated with the key stored in the key storage means 160 (collation control logic 150). Only when the keys match, the following processing becomes possible. If there is no key input, it will wait for this input.

If the user is an authorized user, the command decoder 20 decodes the input command, and if it is an erase command (initialization command), it is passed to the erase control logic 210. In response to this, the timing control circuit 212 causes the C0
= “L” and C1 = “H”, the data of the EPROM 200 (data indicating the number of times initialization is possible) is read. Figure 3 shows this point. Therefore, erasing of data in the memory array 100 is started.

Next, the timing control circuit 212 outputs a signal for fetching the data of the EPROM 200 to C2. This is the point. In addition, in parallel with this, EPR
The data of the OM 200 is input to the OR gate 213. That is, the erase control signal ERS is controlled as shown in the following table to erase the data in the memory array 100. Here, n (number of times initialization is possible) = 3.

After this, when the erasing of the data in the memory array 100 is completed, or when it is considered that the data has been erased (in FIG. 3), the timing control circuit 212 sets C0 to "H", and the data in the memory array 100 is erased. Finish erasing (). Next, a signal for data shift of the EPROM 200 is output to C3, and when the double output is given to the EPROM 200, C1 = "L" is set (), and the data (n) is updated.

[0026]

【table】

As is apparent from the above table, in the third and subsequent erase commands, the data b0 (D1), b of the EPROM 200 is erased.
Even if 1 (D2) and b2 (D3) are all "0", the OR gate 213 is "L", and EN is "1",
ERS = “L”. As a result, this erase command (initialization command) is not recognized and is not executed. That is, EP
If all the data (memory cells) in the ROM 200 is "0", the ERS is "L", and if even one of them is "1", the ERS can be "H". When EN is "0", the output (ERS) of the AND gate 214 is always "L", and erasing of data is prohibited.

[0028]

Industrial Applicability According to the present invention, an inexpensive information card which prevents forgery and has no risk of environmental pollution by enabling reuse and preventing reuse (unauthorized use) a certain number of times or more is obtained. be able to. In addition, data rewriting by an unauthorized person, for example, data initialization, is prohibited to completely prevent unauthorized use.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a prepaid card according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an erase control logic according to an embodiment of the present invention.

FIG. 3 is a timing chart for explaining a processing sequence in the prepaid card according to the embodiment of the present invention.

FIG. 4 is a diagram showing a data structure of a command according to an embodiment of the present invention.

[Explanation of symbols]

100 memory array (user memory) 110 read / write control logic (rewriting means, initialization means) 150 collation control logic (collation means) 160 key storage means 210 erase control logic (initialization means, initialization control means) 200 EPROM (Initialization control means)

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Claims (3)

[Claims] 1. A user memory formed of a non-volatile semiconductor memory capable of rewriting data stored in a plurality of memory cells, and a rewriting unit capable of rewriting data of a plurality of memory cells of the user memory. A key storage means for storing a key indicating an authorized user, and a collating means for permitting rewriting of data by the rewriting means when the input key matches the key stored in the key storing means. And an information card. 2. The rewriting means includes initialization means for enabling initialization of data in the user memory, and initialization control means for limiting the number of times initialization is possible by the initialization means, and the collation is performed. The information card according to claim 1, wherein the means permits initialization by the initialization means when the input key matches the key stored in the key storage means. 3. The information card according to claim 2, wherein the key storage means and the initialization control means are configured by a wired logic.