JPS6117176A - Decoder for code data of terminal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for decoding encrypted data in a terminal.

[Technical front of invention 1! ] Currently, there are devices that process payments by loading information from a credit card into a terminal, but for security reasons, these devices encrypt and record the information on the credit card, and the information is then read into a decryptor inside the terminal. We are trying to decipher it using a device.

Many of the cryptosystems used in such terminals are conventional cryptosystems whose algorithms have been made public, and in such systems, the security of the cryptography depends only on the key. Therefore, in order to further increase security, it is desirable to be able to change the encryption key as frequently as possible.To do this, the encryption key must be sent to the terminal from the host device that is controlling the terminal online. It is better to replace the key on the terminal side.

However, since sending the important key as it is poses a security problem, the key is also encrypted and sent, and the encrypted key is decoded using a decryption device on the terminal to reveal the true key. If this is required at the terminal, security will be improved.

Conventionally, as a device for decoding encrypted data in such a terminal device, the device shown in FIG. 2 is known. That is,
This is a ROM (read only memory) 1 that stores secondary key data for decoding encrypted primary key data that is set to decrypt encrypted data input from the host device that controls the terminal. The secondary key data of the ROMI is loaded into the first sewing register 2, while the primary key data input from the host device is taken into the ciphertext register 4 via the input circuit 3. , the decryption logic 5 decrypts the primary key data taken into the ciphertext register 4 based on the secondary key data of the first sewing register 2 to obtain true key data. is stored in the second sewing register 7 via the output circuit 6. After that, based on the true key data stored in the second sewing register 7, the decryption logic 5 decodes the encrypted data taken into the control circuit 9 via the input circuit 3 and the decoder 8, and decodes the plain data. The data is stored in the output circuit 6 as data, and the plain text data is sent to the data processing section for data processing.

[Problems with the background art] However, in this device, there is only one type of secondary key data for solving the primary key data, and since it is stored in ROMI, it is difficult to change the secondary key data. there were.

[Object of the Invention] This invention was made to solve such a problem, and it provides multiple types of secondary key data, and makes it possible to selectively extract and use each of the secondary key data. It is an object of the present invention to provide an apparatus for decoding encrypted data in a terminal device, which can change the contents of primary key data in accordance with the change of secondary key data, and can further improve security.

[l of invention! Key Points: This invention stores multiple types of secondary key data for respectively decoding multiple types of encrypted primary key data set and encrypted to decrypt encrypted data input from a host device that controls a terminal. a secondary key data memory section; a means for selectively extracting secondary key data corresponding to the type of primary key data from the memory section;
Next key data and encrypted 1 input from the host device
A decryption logic that takes in the primary key data, decrypts the primary key data with the secondary key data, and outputs the true key data for decoding the encrypted data input from the host device; A true key data memory section for storing true key data is provided, and input encrypted data is decrypted using the true key data stored in the true key data memory section.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 11 and 12 each store different types of secondary key data for decrypting encrypted primary key data set to decrypt encrypted data input from a host device that controls the terminal. ROM (read-only memory) and RAM (random access memory). The front gRAM 12 is backed up by a battery 13. The secondary key data in the ROM 11 is taken out to the first sewing register 15 via the first contact 14a of the first changeover switch 14 constituting the selection and retrieval means, and the secondary key data in the RAM 12 is taken out to the first sewing register 15. The material is taken out to the first sewing register 15 via the second contact 14b of the first changeover switch 14. On the other hand, primary key data inputted from the host device and encrypted data inputted externally are taken into the input circuit 16.

The primary key data taken into the input circuit 16 is taken into the ciphertext register 17, and the encrypted data is taken into the control circuit 19 via the decoder 18. 20 is a decryption logic, and this decryption logic 20 takes in the secondary key data taken into the first key register 15 and the primary key data taken into the ciphertext register 17, and decodes the secondary key data into the ciphertext register 17. The primary key data is decrypted and solved based on the key data to obtain the true key data. The obtained true key data is then sent to the output circuit 21. The true key data taken into the output circuit 21 is loaded into the RAM 12 via the first contact 22a of the second changeover switch 22 interlocked with the first changeover switch 14, and the M2 changeover switch 22 The second sewing register 23 is loaded through the second contact 22b of the sewing machine.

The decoding logic 20 also includes: The true key data is extracted from the second sewing register 23 or the RAM 12, and based on the true key data, the encrypted data from the control circuit 19 is decoded and sent to the output circuit 2 as plain text data.
It is sent to 1. Plaintext data DATA taken into the output circuit 21 is sent to a data processing section (not shown). The input circuit 16 and the output circuit 21 are controlled by the control circuit 19, and the input circuit 16 sends data to the ciphertext register 17 or the decoder 18.
The output circuit 21 selectively outputs the data to the RAM.
12. It is designed to selectively output to the second sewing register 2-3 side or the data processing section side.

In the apparatus according to the embodiment of the present invention configured as described above, the first
When the changeover switch 14 and the second changeover switch 22 are set to the second contacts 14b and 22b, respectively, as shown in the figure, the secondary key data stored in the RAM 12 is transferred to the first
is loaded into the first sewing register 15 via the second contact 14b of the changeover switch 14. In this state, input circuit 1
When primary key data is input from the host device to 6, the data is stored in the ciphertext register 17. Then, in the decryption logic 20, the primary key data of the ciphertext register 17 is decrypted and decrypted based on the secondary key data of the first sewing register 15, and the true key data is obtained. This true key data is sent to the output circuit 21, and the second
is stored in the second sewing register 23 via the second contact 22b of the changeover switch 22. In this way, the setting of true key data for decoding the encrypted data is completed. Once the setting of this true key data is completed, from then on, when encrypted data is input from the outside to the input circuit 16 from a credit card, etc., the encrypted data is taken into the control circuit 19 via the decoder 18, and the decryption logic 20 The key data is decrypted based on the true key data stored in the second sewing register 23 and converted into plain text data. Then, this plaintext data is output to the data processing section via the output circuit 21 and subjected to data processing.

If you want to change the type of secondary key data in this device, use the first changeover switch 14 and the second changeover switch 2.
2 and set the first contact 14a122a side. Thus, the secondary key data stored in the ROM 11 is now loaded into the first sewing register 15 via the first contact 14a of the first changeover switch 14. By doing this, the contents of the primary key data input from the host device can also be changed in accordance with the secondary key data. Then, the decryption logic 2° decrypts and decodes the primary key data of the cipher text register 17 based on the secondary key data stored in the first sewing register 15 as described above, and decodes the true key. Ask for data. This true key data is outputted to the output circuit 21, and from the output path 21 is transmitted to the RA via the first contact 22a of the second changeover switch 22.
It will be stored in M12. Thereafter, encrypted data input to the input circuit 16 will be decrypted and converted into plain text data based on the true key data stored in this RAM.

In this way, the secondary key data is stored not only in the ROM 11, but also in the RA
By also setting M12, the first changeover switch 1
Different types of secondary key data can be selectively taken out by the switching operation in step 4, and the secondary key data can be easily changed. Since the secondary key data can be changed in this way, the primary key data can also be changed accordingly, making it possible to change the key data transmitted from the host device. Therefore, if the primary key data is leaked, the primary key data can be immediately changed, thereby further improving security.

Note that if the secondary key data is set using a company number, store number, terminal number, etc., it is easy to confirm the data, so the key data can be easily set, and the data can be easily managed.

In the above embodiment, two types of secondary key data are set, but the invention is not limited to this, and three or more types may be set and selectively retrieved. .

[Effects of the Invention] As detailed above, according to the present invention, a plurality of types of secondary key data are provided, and each of the secondary key data can be selectively extracted and used, so that the contents of the primary key data Part 2
It is possible to provide an apparatus for decoding encrypted data in a terminal device, which can be changed in accordance with changes in next key data and can further improve security.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 11...ROM (read only memory), 1
2...RAM (random access memory), 1
4... first changeover switch, 15... first sewing register, 19... control circuit, 20... decoding logic, 22... second changeover switch, 23... th 2 sewing register.

Claims (1)

[Claims] A secondary key data memory that stores multiple types of secondary key data for each of the multiple types of encrypted primary key data set to unravel the encrypted data input from the host device that controls the terminal. a means for selectively retrieving secondary key data corresponding to the type of primary key data from the memory portion; and encrypting the secondary key data retrieved by the means and input from the host device. a decryption logic that takes in primary key data, decrypts the primary key data with secondary key data, and outputs true key data for decrypting encrypted data input from the host device; A true key data memory section for storing true key data output from the logic is provided, and input encrypted data is decrypted by the true key data stored in the true key data memory section. A device for decoding encrypted data in a terminal device.