JPH10105471A - Semiconductor memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit a security protecting function to be the higher one by waiting password code data for plural stages and recognizing that both of a semiconductor memory device and the device to which it is connected are normal. SOLUTION: The plural areas 4a, 4b,...4n of first, second,...n-th password code data are provided and data of the area 4a of password code data is compared with inputted data so as to be inquired. At the time of coincidence, succeeding data is inputted and compared with data of the area 4b of password code data so as to be inquired. This processing is repeated by the number of set stages and access to a storage area is made to be possible when the data comparison inquiry of whole password codes is coincided. A random number is generated by data of the respective password codes and inputted data so that both of the semiconductor memory device and the interface of the device to which it is connected are recognized to be normal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor memory device having a plurality of areas for security code data and areas for reproduction security code data in a divided storage area.

[0002]

2. Description of the Related Art A conventional semiconductor memory device of this type has a storage means composed of a plurality of continuous divided storage areas as shown in FIG. In FIG. 4, reference numeral 1 denotes an area of manufacturer code data for storing a card manufacturer code;
2 is an area of issuer code data for storing a code of a card issuer, 3a is a first spare area, 3b is a second spare area, 3c is a third spare area, 3d is a fourth spare area, and 4 is a password of the card. An area for security code data for storing codes, an error counter area for storing a count value of the number of times of incorrect input of a security code, an area for condition code data for determining permission / prohibition of writing to all areas of the storage area,
7a is a first application area, and 7b is a second application area.

In the above-described operation of reading and writing to each area of the divided storage area, in addition to a write permission command for permitting the writing, writing cannot be performed unless certain conditions are satisfied for each area. Similarly, conditions are set for reading as well, and the conditions will be described below.

The area 1 of the manufacturer code data is writable when the condition of the area 6 of the condition code data is matched, and is not writable when the condition of the area 6 of the condition code data is not matched. Further, reading is possible regardless of conditions.

The area 2 of the source code data becomes writable when the condition of the area 6 of the condition code data coincides, and becomes impossible when the condition of the area 6 of the condition code data does not coincide. Further, reading is possible regardless of conditions.

[0006] First, second, third and fourth spare areas 3a,
3b, 3c, and 3d become writable when the condition code and area code in area 6 of the condition code data match, and cannot be written when the condition or code in area 6 of the condition code data do not match. Further, reading is possible regardless of conditions.

The area 4 of the personal identification code data becomes writable when the personal identification codes match, and becomes impossible when the personal identification codes do not match. Reading is impossible under any conditions.

The error counter area 5 counts the number of erroneous inputs sequentially from the first bit when the passwords do not match. When the passwords match, the count value of the number of erroneous inputs stored in the error counter area 5 is: Automatically reset.

The condition code data area 6 becomes writable when the passwords match, and cannot be written when the passwords do not match. Similarly, reading is enabled when the passwords match, and impossible when the codes do not match.

[0010] The first and second application areas 7a,
7b allows writing and reading when the condition code of the area 6 of the condition code data and the password match, and enables reading only when the condition of the area 6 of the condition code data does not match. Further, when the passwords do not match, the reading becomes impossible.

Next, the operation of the semiconductor memory device constituted by the areas of the divided storage areas under the above conditions will be described.

First, in a read operation from a semiconductor memory device, when a read command and address data are sequentially input as input data, data in a stored storage area is output. This is because the state of the internal storage area does not change by matching the personal identification code before reading, so that each area other than the area 4 of the personal identification code data can be continuously read.

In the writing operation, writing is performed by sequentially inputting a write enable command, a write command, address data, and write data. However, in the write-protected state, when the passwords do not match, and when the condition of the condition code data area 6 is not satisfied, the data in the internal storage area is not rewritten, and Is temporarily reset.

The personal identification code compares and inquires the internal data in the personal identification code data area 4 with the data inputted from the outside, and permits access to the internal storage area when they match. When the comparison and inquiry result in a mismatch, the number of errors is stored in the error counter area 5. When the number of errors reaches a preset number, the operation of comparing and inquiring the personal identification code thereafter is not performed, and access to the internal storage area becomes permanently impossible. If the comparison inquiry between the personal identification code and the input data matches less than the set number of times, the count value of the error counter area 5 is reset.

[0015]

However, the semiconductor memory device having such a configuration is not sufficient in terms of security because the access permission is made only once by the comparison inquiry using the personal identification code. Also, the number of errors in the comparison inquiry between the personal identification code and the input data exceeds a certain number of times, and furthermore, the used semiconductor memory device cannot be reproduced, so that it is used up and the price becomes high. There was a problem that there is.

The present invention has been made to solve the above-mentioned problem of the prior art, and has a plurality of password code data, and confirms that both a semiconductor memory device and a device to which the semiconductor memory device is connected are authentic. It is an object of the present invention to provide a semiconductor memory device that is more cost-effective by making the security function of the semiconductor memory device more sophisticated and having a reproducible specification.

[0017]

In order to achieve this object, a semiconductor memory device according to the present invention comprises a storage area having at least two areas of manufacturer code data and an area of issuer code data. An area for password code data, an area for an error counter that counts the number of incorrect input of the password, an area for condition code data for determining whether to allow or prohibit writing to all areas of the storage area,
A storage means which is divided into an area of personal code data which is personal data and stores a plurality of continuous storage areas for storing each data in word units, and data written in an area of input data and personal identification code data And random number generating means for generating a random number according to the above, and input / output means for performing input / output processing of each data.

Further, the storage means is provided with an area for at least two pieces of password code for reproduction and an area for a reproduction counter for counting the number of times of reproduction.

According to the above-mentioned configuration, it is possible to have a plurality of personal identification code data, perform a comparison inquiry of the personal identification code in a plurality of stages, and make it possible to access the storage area only at the time of matching at all the stages. By the random number generating means for generating a random number based on the data in the area of the personal identification code data, it is possible to confirm that both the semiconductor memory device and the device connecting it are authentic.

Further, the semiconductor memory device has a plurality of reproduction security code data, performs comparison inquiry of the reproduction security code in a plurality of stages, and can reproduce and reuse the semiconductor memory device only when all the stages match.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of the semiconductor memory device according to the first embodiment of the present invention. 11 is a storage area (memory array) as storage means, 12 is a random number circuit which is a means for generating a random number based on input data and written secret code data, 13 is an I / O buffer for temporarily storing input / output data, 14 is I /
An address decoder 15 decodes address data from the O buffer 13, and 15 is a storage area (memory array) 11 and an I / O
The data register 16 for data exchanged between the buffers 13 decodes the mode from the input data,
Mode decoder logic for controlling the address and data input / output of the area of the divided storage area.

FIG. 2 shows the configuration of the divided storage area of the storage means of the semiconductor memory device according to the first embodiment. Here, components corresponding to the components described in FIG. 4 showing the conventional example are denoted by the same reference numerals, and the same applies to the following drawings. In FIG. 2, 1 is an area of manufacturer code data, 2 is an area of issuer code data, 4a, 4b,.
The area of the n-th secret code data, 5 is an error counter area, 6 is an area of condition code data, 7a is a first application area, 7b is a second application area, and 10 is an area of personal code data.

The configuration of the partitioned storage area in the first embodiment is such that the area 4 of the password code data having the configuration described in FIG. Password code data areas 4a, 4b,-4n
Are provided. As a result, the security code first performs a comparison inquiry between the data in the area 4a of the security code data and the input data. When they match, the next security code data is input, and the security code data area 4b is input.
Make a comparison query with the data in. This operation is repeated for the set number of steps, and the access to the storage area becomes possible when the data comparison inquiries of all the passwords match.

Further, both the semiconductor memory device and the interface of the device to which the semiconductor memory device is connected are authentic by the random number circuit 12 for generating a random number based on the data of each security code and the input data shown in FIG. Can be confirmed.

From the above, by repeating the predetermined number of steps of confirmation using the personal identification code, it is also possible that the random number circuit 12 ensures that the interface between the semiconductor memory device and the device to which the semiconductor memory device is connected is authentic. As a result, the security accuracy of the semiconductor memory device becomes higher.

Next, FIG. 3 shows the configuration of the divided storage area of the storage means of the semiconductor memory device according to the second embodiment of the present invention. In FIG. 3, 1 is an area for manufacturer code data, 2 is an area for issuer code data,
a, 4b, to 4n are areas for the first, second to n-th code data, 5 is an error counter area, 6 is an area for condition code data, 7a is a first application area,
7b is a second application area, 8a, 8b,..., 8n are first, second,.
Is a reproduction counter area, and 10 is an area for personal code data.

The configuration of the divided storage area in the second embodiment is different from the divided storage area described in the first embodiment in that areas 8a, 8b, 8b, 8b, 8n and the reproduction counter area 9 are added, and other configurations and operations are the same as those of the first embodiment of the present invention, and therefore description thereof is omitted.

The first, second, second to n-th reproduced code data areas 8a, 8b, to 8n and the reproduction counter area 9 are provided, and a reproduction function is added to the semiconductor memory device. To the area 8a of the n-th reproduced security code data,
A comparison inquiry is made between the data of the reproduction security code data stored in 8b and .about.8n and the input data, and when all of the predetermined number of stages match, the semiconductor memory device can be reproduced.

For example, in a semiconductor memory device in which the count value of the error counter area 5 exceeds a preset number of erroneous inputs and access to the internal storage area becomes impossible, the count value of the error counter area 5 is reset. And an area 4 of the first, second, and nth security code data.
The data of the new personal identification code is written, and the number of times of reproduction is stored in the reproduction counter area 9 so that the semiconductor memory device can be reused.
Further, the count value of the reproduction counter area 9 is also set in advance, and cannot be reused more than a certain number of times.

Further, as in the first embodiment, the semiconductor memory device and the interface of the device to which the semiconductor memory device is connected are reproduced by the random number circuit 12 for generating a random number based on the data of the input data and the reproduction code data. It can be confirmed that it is a regular one to be performed. Also, it is assumed that the reproduction security code has a greater number of steps than the security code as far as the storage area allows.

From the above, it is possible to increase the accuracy of security protection of a semiconductor memory device and enable reuse.

[0032]

As described above, according to the present invention,
A semiconductor memory having a plurality of levels of personal identification code data, performing a plurality of stages of comparing and inquiring each personal identification code data with input data, and having a random number circuit for generating a random number based on data of the personal identification code data and input data. The security of the device can be more accurate.

Also, by providing a plurality of stages of the area of the reproduction security code data, the comparison of the reproduction security code data with the input data is performed in a plurality of stages, thereby enabling the reproduction of the semiconductor memory device. This brings about the effect that the price can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a semiconductor memory device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a partitioned storage area of a storage unit of the semiconductor memory device according to the first embodiment.

FIG. 3 is a diagram showing a configuration of a partitioned storage area of storage means of a semiconductor memory device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a divided storage area of storage means in a conventional semiconductor memory device.

[Explanation of symbols]

1 ... area of manufacturer code data 2 ... area of issuer code data 3a, 3b, 3c, 3d ... first, second and second
3rd and 4th spare areas, 4 ... area of security code data, 4a, 4b,-4n ... areas of first, second, 2nd-nth security code data, 5 ... error counter area, 6
… Condition code data area 7a, 7b… first and second
Application area, 8a, 8b,-8n ... 1st, 1st
Areas of second to n-th reproduced security code data, 9: reproduction counter area, 10: personal code area, 11: storage area (memory array), 12: random number circuit, 13: I / O
Buffer, 14 ... address decoder, 16 ... mode decoder logic.

Claims (2)

[Claims] 1. An area of a manufacturer code data, an area of an issuer code data, an area of a security code data having at least two or more, and an error counter for counting the number of erroneous input of the security code in a storage area. A divided storage area for storing each data in word units by dividing into an area, an area for condition code data for determining permission / inhibition of writing to all areas of the storage area, and an area for personal code data as personal data. Storage means, a random number generation means for generating a random number based on input data and data written in the area of the password code data, and an input / output means for performing input / output processing of each data. A semiconductor memory device. 2. An area for a manufacturer code data, an area for an issuer code data, an area for a password code having at least two codes, and an error counter for counting the number of incorrect input of the password. An area, an area of condition code data for determining permission / inhibition of writing to all areas of the storage area, an area of personal code data which is personal data, an area of security code data for reproduction having at least two or more, It is divided into an area of a reproduction counter for counting the number of times of reproduction, and a storage means comprising a plurality of continuous divided storage areas for storing respective data in word units, and written in an area of input data and the above-mentioned password code data. A random number generating means for generating a random number based on data; and an input / output means for performing input / output processing of each data. A semiconductor memory device characterized by the above-mentioned.