JPH03147193A - Magnetic card processing system - Google Patents

Abstract

PURPOSE:To prevent a magnetic card from being copied even when ciphered data are taken from a communication line by making ciphered data, which are transmitted from a host to a card reader/writer terminal, different from ciphered data to be transmitted from the card reader / writer terminal to the host. CONSTITUTION:When data are written from a host 2 to a magnetic card 7, source data X0 to be written are ciphered by ciphering means 5a and 5b. When data X2 written to the magnetic card 7 are read into the host 2, the ciphered data written into a magnetic card 3 are restored to the source data X0 by deciphering means 6b and 6a. In such a case, ciphering and deciphering are executed so that ciphered data X1 obtained by the ciphering means 5a can be different from ciphered data X3 obtained by the deciphering means 6b. Thus, even when the ciphered data are taken from the communication line, the copy of the magnetic card can not be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic card processing system used for prepaid cards and the like.

[Prior Art] As shown in FIG. 6, in a conventional magnetic card processing system, a communication line 106 is wired between a host 102 and a card reader terminal 104. Data is transmitted and received between the terminals 104. The host 102 is provided with an encryption means 108, a decryption means 110, and a transmission circuit 112. The card reader/writer terminal 104 is provided with a transmission circuit 114 and a card reader/writer 116 .

When writing data from the host 102 to the magnetic card 118, the encryption means 108 of the host 102
The original data X0 is encrypted using a certain algorithm (for example, an algorithm that adds "8" to the original data X to be transmitted).

+8) is encrypted. This encrypted data X1 is transmitted from the transmission circuit 112 to the communication line 106. The card reader/writer terminal receives the encrypted data X1 transmitted to the communication line 106 via the transmission circuit 114. The received encrypted data X is written to the magnetic card 118 by the card reader/writer 116.

The data written on the magnetic card 118 is transferred to the host 102.
104 on the card reader/writer terminal.
, the encrypted data X written on the magnetic card 118 is read by the card writer 116. The read encrypted data X is sent to the transmission circuit 114
, and is transmitted to the communication line 106 . The host 102 receives the encrypted data X transmitted to the communication line 106 via the transmission circuit 112. The received encrypted data It is decoded and returned to the original data X0.

[Problems to be Solved by the Invention] In the conventional magnetic card processing system as described above, only the host is provided with an encryption means and a decryption means. Therefore, the data transmitted to the communication line when data is written from the host to the magnetic card is the same as the data transmitted to the communication line when the host reads data written on the magnetic card. Furthermore, these data also match the data written on the magnetic card. As a result, if another communication device (for example, a microcomputer) is connected to the communication line, when writing data from the host to the magnetic card, or when reading data written on the magnetic card to the host, Encrypted data X is acquired from the communication device. Therefore, the encrypted data X can be written to another magnetic card using a card writer connected to a communication device or a card reader/writer terminal used in a magnetic card processing system. This made it possible to illegally make copies of magnetic cards.

An object of the present invention is to solve the above-mentioned technical problems and provide a magnetic card system in which a copy of a magnetic card cannot be created even if encrypted data is taken from a communication line.

[Means for Solving the Problems] In order to solve the above-mentioned technical problems, the present invention has the following configuration.

That is, the magnetic card processing according to claim (1) encrypts the original data to be written by an encryption means when writing data from the host to the magnetic card, and when reading the data written on the magnetic card to the host. is a device that restores encrypted data written on a magnetic card to the original data by a decryption means and sends and receives data between a host and a card reader/writer terminal via a communication line, wherein the encryption means and The decryption means is distributed between the host and the card reader/writer terminal, and decrypts encrypted data on the communication line transmitted from the host to the card reader/writer terminal and encrypted data on the communication line transmitted from the card reader/writer terminal to the host. It is characterized by different things.

The magnetic card processing system according to claim (2) encrypts the original data to be written using an encryption means when writing data from the host to the magnetic card, and when reading data written on the magnetic card to the host. Encryption of the encryption means in a device that restores encrypted data written on a magnetic card to the original data using a decryption means and sends and receives data between the host and the card reader/writer terminal via a communication line. The data is encrypted by successively increasing the encryption level by sequentially performing multiple steps of encryption processing on the original data. The encryption level is gradually lowered, and the encryption level on the communication line when writing data from the host to the magnetic card is different from the encryption level on the communication line when reading data written on the magnetic card to the host. The encryption level written on the magnetic card is different from the encryption level on the communication line.

[Operation] In the magnetic card processing system according to claim (1), the encryption means and the decryption means are distributed in the host and the card reader/writer terminal, respectively. The encrypted data on the communication line transmitted from the host to the card reader/writer terminal is different from the encrypted data on the communication line transmitted from the card reader/writer terminal to the host.

Therefore, even if the encrypted data is taken from the communication line, a copy of the magnetic card cannot be made.

In the magnetic card processing system of claim (2),
The encryption performed by the encryption means is such that the original data is sequentially subjected to a plurality of steps of encryption processing to successively increase the encryption level. The decryption performed by the decryption means sequentially performs decryption processing that reverses the encryption processing in a plurality of steps to sequentially lower the encryption level. The encryption level on the communication line when data is written from the host to the magnetic card is different from the encryption level on the communication line when data written on the magnetic card is read into the host.

Furthermore, the encryption level on these communication lines is also different from the encryption level written on the magnetic card.

Therefore, even if the encrypted data is taken from the communication line, a copy of the magnetic card cannot be made. Further, the encryption means and the decryption means can be easily configured, and furthermore, the encryption means and the decryption means can be easily divided. Furthermore, it becomes easy to distribute the encryption means and the decryption means to the host and the card reader/writer terminal.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram of a magnetic card processing system showing an embodiment of the present invention.

In this magnetic card processing system, a communication line 4 is wired between the host 2 and the card reader/writer terminal 3, and data is transmitted and received between the host 2 and the card reader/writer terminal 3 via the communication line 4. Encryption means 5a and 5b are distributed in the host 2 and the card reader/writer terminal 3, respectively. Furthermore, decoding means 6a and 6b are distributed in the host 2 and the card reader/writer terminal 3, respectively. When writing data from the host 2 to the magnetic card 7, the original data x0 to be written is encrypted by the encryption means 5a, 5b. When data X2 written on the magnetic card 7 is read into the host 2, the encrypted data written on the magnetic card 3 is returned to the original data X0 by the decryption means 6b and 6a.

Here, encrypted data X1 obtained by the encryption means 5a and encrypted data x obtained by the decryption means 6b
Encryption and decryption are performed in a manner different from 3.

In this magnetic card processing system, the encryption means 5a and 5b encrypt the original data X. The encryption level is increased sequentially by sequentially applying multiple steps of encryption processing to the data. The decryption by the decryption means 6b and 6a is performed by sequentially performing a decryption process that reverses the encryption process in a plurality of steps to sequentially lower the encryption level. The encryption level on the communication line when data is written from the host to the magnetic card is different from the encryption level on the communication line when data written on the magnetic card is read into the host. Furthermore, the encryption level on these communication lines is also different from the encryption level written on the magnetic card.

FIG. 2 is an example of a detailed circuit diagram.

This magnetic card processing system 21 includes a host 22, a card reader/writer terminal 24, and a communication line 26 wired between the host 22 and the card reader/writer terminal 24. Data is transmitted and received between the host 22 and the card reader/writer terminal 24 via the communication line 26 .

The host 22 has CPtJ32, R connected to the bus 31.
It includes an OM 33, a RAM 34, a transmission circuit 35, a CRT 36, a keyboard 37, a card reader 38, a floppy disk device 39, a printer 40, and the like. Transmission circuit 35
A communication line 26 is connected to. The card reader/writer terminal 24 includes a CPU 52 and a ROM connected to the bus 51.
53, a RAM 54, a transmission circuit 55, a card reader/writer 56, and the like. The transmission circuit 55 includes a communication line 26
or connected.

In the ROM 33 of the host 22, there are programs shown in step m to step m4 of the card writing process shown in (1) in FIG. 3, and programs shown in step n to step n of the card reading process shown in (2) in FIG. The programs shown in are stored. In addition, R of the card reader/writer terminal 24
The OM33 includes programs shown in step m to step ms of the card writing process shown in (1) of FIG. 3, and step n of the card reading process shown in (2) of FIG.
- Programs shown in steps n4 and the like are stored.

Encryption process Z1 of step m2 of card writing process,
Step m! The encryption process Z2 in step m6 and the encryption process Zj in step m6 constitute an encryption means.

Algorithm A I A ! performed in each encryption process Zll z,, Zs. + A s (for example,
Addition of rlJ, addition of "2", addition of "5") constitute one certain algorithm (addition of "8"). These three encryption processes Z, to Z are performed sequentially, the encryption level is increased one after another, and one encryption process is completed.

Decoding process Yls in step n2 of card reading process
The decoding process Y3 in step m and the decoding process Y in step n6 constitute a decoding means.

Decoding process Y1. Algorithm B1. is performed in Y t and Y a respectively. Bt and Bs constitute one algorithm. Algorithm B+ performed in the decryption process Y1 is a reverse version of the algorithm A performed in the encryption process Z1 (subtraction of "1"). Algorithm B performed in decoding process Y1.

is a reverse version of the algorithm At used in the encryption process Z (subtraction of "2"). The algorithm Bs performed in the decryption process Y is the inverse of the algorithm Δ performed in the encryption process 2 ("subtraction of 5J").These three decryption processes Y, ~Y1 are sequentially traced back. The encryption level is sequentially lowered, and one decryption process is completed.This situation is shown in the data flow in Figure 4.The relationship between the encryption process and the algorithm used, and 1. Table 1 summarizes the relationship between the summerization process and the algorithms used.

In the first front card writing process, the host 22 performs the following process. First, the original data X0 to be stored in the magnetic card 28 is input from the keyboard 37 or the like (step m). Original data X0 input from the keyboard 37
is stored in the RAM 34, displayed on the CRT 36, and stored on the floppy disk attached to the floppy disk device 39. Next, encryption processing Z is performed using algorithm A, and the original data X0 becomes encrypted data X.
, (XI=XO+1) (step m2) (encryption level 1). This encrypted data X1 is stored in RAM 3
4 is stored. Next, encryption processing Z2 is further performed using algorithm A2, and the encrypted data X becomes encrypted data X z (X 2 = X I + 2 =
X o + 3) l:stLru (step m3) (
Encryption level 2). This encrypted data X2 is stored in RAM3
4 is stored. Next, the encrypted data X2 is transmitted from the transmission circuit 35 to the communication line 26 (step m4)
.

In the card writing process, the card reader/writer terminal 24
The following processing is performed in . The encrypted data X transmitted to the communication line 26 is received by the transmission circuit 55 (step ms). The received encrypted data X is stored in the RAM 54.

Next, the received encrypted data X2 is subjected to encryption processing Zs by algorithm A3, and the encrypted data X2 is
s (X s = X 2 + 5 = X t
+ 7 = X o + 8 ) (step m
6) (Encryption level 3).

Next, the encrypted data X3 is written to the magnetic card 28 (step m7), and the magnetic card 28 is ejected from the card reader/writer 56 (step ms). In this way, encrypted data of content Xs (x0+8) is written to the magnetic card 28. Writing to the magnetic card 28 is completed as described above.

Next, reading data from the magnetic card 28 will be explained. In the card reading process, the following process is performed at the card reader/writer terminal 24. When the magnetic card 28 is inserted into the card reader/writer 56, encrypted data Xs (xs=xo
+8) (encryption level 3) is the card reader/writer 56
(step n,). The read encrypted data X3 is stored in the RAM 54. Next, decoding processing Y3 is performed using algorithm B3,
Encrypted data X3 is encrypted data X2 (Xi=X1 5
=X6+3) (step n2) (encryption level 2).

This encrypted data X2 is stored in the RAM 54.

Then, decryption processing Y2 is further performed using algorithm B2, and the encrypted data X2 becomes encrypted data XI.
(XI=X2 2=XO+1) (step n3
) (encryption level 1). This encrypted data X is RA
It is stored in M54. Next, the encrypted data X is transmitted from the transmission circuit 35 to the communication line 26 (step n
a).

In the card reading process, the host 22 performs the following process. The encrypted data X transmitted to the communication line 26 is received by the transmission circuit 35 (step n
,). Received encrypted data X.

is stored in the RAM 34. Next, the received encrypted data X is subjected to decryption processing Y using algorithm B, and is returned to original data X0 (Xo=X11) (step ns). Next, in step n7, the decrypted original data X0 is looked at and it is determined whether the magnetic card 28 inserted into the card reader/writer 56 is an unauthorized card. This determination is made, for example, as follows.

If the decoded data matches the data stored on the floppy disk loaded in the floppy disk device 39, it is determined that the data is genuine. If the decrypted data does not match the data stored on the floppy disk, it is determined to be fraudulent. If the card is invalid, step n.

The process proceeds to Step 1, instructs the card reader/writer terminal 24 to eject the magnetic card 28, and returns to the card reading process. If it is not a fraudulent card, i.e. magnetic card 2
If 8 is genuine, the process proceeds to step n8, where the host 22 performs processing. For example, in a prepaid card system, this process is as follows. Check the amount of the item being purchased and the remaining amount, and if the amount of the item is within the remaining amount, give OK and reduce the remaining amount by the amount of the item,
If it exceeds the remaining amount, issue a No. When step n is completed, the process proceeds to step n and the magnetic card 28 is ejected.

In this way, the host 22 receives the original data of the content Xo.

In this magnetic card processing system 21, the host 22 performs encryption processing z1. The encryption processing Zs and the decryption processing Y*, Zs are distributed and arranged in the card reader/writer terminal 24. Therefore, the encryption level of the encrypted data transmitted from the host 22 to the card reader/writer terminal 24 and the card reader/writer terminal 2
4 to the host 22. Furthermore, the encryption level of these encrypted data and the encryption level of the encrypted data stored in the magnetic card are also different. In this way, since each piece of encrypted data has a different encryption level, each piece of encrypted data also has a different value.

Therefore, even if data is obtained from the communication line 26, the magnetic card cannot be illegally copied.

For example, encrypted data X! transmitted to the communication line 26 during card writing processing! Assume that the information is acquired by another communication device (for example, a personal computer). Since the data acquired by this communication device is X, the data written to the magnetic card using the card writer is X2. Therefore, it is not possible to create a magnetic card with the content of data X. Even if this fraudulently created magnetic card is inserted into the card reader/writer 56 of the magnetic card processing system 21, the data finally received by the host 22 is X, -8 = X, -5, which is the original data. You cannot take X0. Therefore, this fraudulently created magnetic card cannot be used.

Next, assume that the encrypted data XI (X1=XO+1) transmitted to the communication line 26 during the card reading process is acquired by another communication device. Since the data acquired by this communication device is X, the data written to the magnetic card using a general card writer is X,
It is. Therefore, a magnetic card with the contents of data X3 cannot be created. Even if this magnetic card is inserted into the card reader/writer 56 of the magnetic card processing system 21, the data finally received by the host 22 is X, -5=
X.

-7, and the original data X0 cannot be received.

Therefore, in this magnetic card processing system 21, even if data is obtained from the communication line 26 and a card is created illegally, it is impossible to create a magnetic card with the same content as a legitimate magnetic card.

In the embodiment described above, the host 22 has two encryption processes Z-
, Zz and one decryption process Y, and one encryption process Z and two decryption processes Ys and Yz are arranged in the card reader/writer terminal 24. However, if the encryption processing and decryption processing of the host 22 are arranged in three or more ways, or the card reader/writer terminal 2
A magnetic card processing system may be constructed by arranging three or more encryption processes and decryption processes described in 4.

Also, the encryption process is changed from Z1 to 2. -2. The decoding process is performed backwards in the order of Z, →Z, →Z, but it is possible to randomize the order of processing, such as decoding in the order of Z, →z, -22. You can also do this.

In addition, the algorithm for each decryption process is the opposite of the algorithm for each encryption process, but for example, as shown in Figure 5, the algorithm for each decryption process is the opposite of the algorithm for each encryption process. It is also possible to use a different algorithm. In this case, by simply providing one encryption process P and one decryption process Q in the host 22 and providing one encryption process P2 and one decryption process Q1 in the card reader/writer terminal 24, The encrypted data on the communication line 26 can be different (X+ and X,゛).

Furthermore, although examples of encryption/decryption have been given using addition/subtraction, multiplication/division algorithms, other commonly used encryption/decryption methods such as numerical replacement may also be used.

In the above embodiment, the card writing process and the card reading process are described as separate processes, but in a prepaid card system, card reading and writing are generally performed as a series of processes, so the remaining amount calculated in step n8 and the number identifying the card (included in the read data in step n) may be subjected to the processing in step m, and the following steps m3 to m8 may be executed.

At this time, X0 = card number + remaining amount, and RAM34
Needless to say, this is used to check the cards stored in the next step n.

[Effects of the Invention] In the magnetic card processing system according to claim (1), the encryption means and the decryption means are distributed in the host and the card reader/writer terminal, respectively, and the communication line is transmitted from the host to the card reader/writer terminal. The encrypted data in the card reader/writer terminal and the encrypted data in the communication line transmitted from the card reader/writer terminal to the host are configured to be different.

Therefore, even if the encrypted data is taken from the communication line, a copy of the magnetic card cannot be made.

In the magnetic card processing system according to claim (2), the encryption by the encryption means is performed by successively increasing the encryption level by sequentially performing multiple steps of encryption processing on the original data, and the encryption by the decryption means is performed by successively increasing the encryption level. Decryption is a multi-step decryption process that reverses the encryption process and sequentially lowers the encryption level.When data is written from the host to the magnetic card, the encryption level in the communication line is the same as the magnetic card. The encryption level on these communication lines is different from the encryption level on the communication lines when data written on the magnetic card is read into the host, and the encryption level on these communication lines is also different from the encryption level written on the magnetic card.

Therefore, even if the encrypted data is taken from the communication line, a copy of the magnetic card cannot be made. Further, the encryption means and the decryption means can be easily configured, and furthermore, the encryption means and the decryption means can be easily divided. Furthermore, it becomes easy to distribute the encryption means and the decryption means to the host and the card reader/writer terminal.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a magnetic card processing system showing an embodiment of the present invention, Fig. 2 is an example of a detailed circuit diagram, and Fig. 3 (1) and (2) are data stored in ROM33 and ROM53. Flowchart of card writing processing and card reading processing, FIG. 4 is a diagram showing the data flow, FIG. 5 is a diagram showing the data flow of another embodiment of the present invention, and FIG. 6 is the entire conventional magnetic card processing system. FIG. 2.22...Host 3.24...Card reader/writer terminal 4.26...
Communication lines 5a, 5b...Encryption means 6a, 6b...Decryption means 7.28...Magnetic card Fig. 4 Fig. 5

Claims (2)

[Claims] (1) When writing data from a host to a magnetic card, the original data to be written is encrypted by an encryption means, and when reading data written to a magnetic card to the host, it is encrypted and written to the magnetic card. In a magnetic card processing system, data is returned to the original data by a decoding means, and data is transmitted and received between a host and a card reader/writer terminal via a communication line.
The encryption means and the decryption means are distributed in the host and the card reader/writer terminal, respectively, and the encrypted data in the communication line transmitted from the host to the card reader/writer terminal and the communication transmitted from the card reader/writer terminal to the host. A magnetic card processing system that is different from the encrypted data on the line. (2) When writing data from the host to a magnetic card, the original data to be written is encrypted using an encryption means, and when reading the data written to the magnetic card to the host, it is encrypted and written to the magnetic card. In a magnetic card processing system in which data is returned to the original data by a decryption means and data is sent and received via a communication line between a host and a card reader/writer terminal, the encryption by the encryption means restores the original data to the original data. The encryption level is gradually increased by sequentially performing multiple steps of encryption processing, and the decryption method uses multiple steps of sequentially performing decryption processing that reverses the encryption processing to sequentially lower the encryption level. The encryption level on the communication line when writing data from the host to the magnetic card is different from the encryption level on the communication line when reading the data written on the magnetic card to the host. A magnetic card processing system characterized in that the encryption level of the communication line is different from the encryption level of the communication line.