JPH10126406A - Data cipher system in network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To limit time that is needed for encipher and decoding at a transmission destination without damaging the confidentiality of data through encipher by making data image data and inserting the key of cryptograph of the data into transmission information. SOLUTION: This system is provided with a serial in parallel out shift (S/P) register 12, encipher processing parts 13a and 13b and a parallel in serial out (P/S) register 14. It does not perform any encipher to an SMTP header 9 which does not need security, performs strong encipher to transmission information 10 which includes much significant information in the part 13b, performs weak encipher to image data 11 in the part 13a and then moves the contents from the S/P register 12 to the P/S register 14. That is, it performs a strong cipher system such as elliptic cipher, an RSA, a DES and nonlinear shift register to the transmission information 10 and performs a weak cipher system such as a linear shift register, simple inversion and replacement to the image data 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to data transmission on a network, and more particularly to an encryption method for image data.

[0002]

2. Description of the Related Art In recent years, a wide area network such as the Internet has been developed, and data transmission using this network has been generally performed. FIG. 4 is a conceptual diagram showing a form of a system for transmitting facsimile information between terminals using the Internet.

[0003] The terminal 1 is provided with data (text,
Image) is transmitted to the fax device 5 via the other terminal 3 or the gateway 4 via the Internet 2.

The terminal 1 prepares data in a frame format as shown in FIG. Image data to be transmitted
Transmission information 7 describing transmission destination or transmission source information (FAX number, password, user name, etc.) is added immediately before 6.The Internet mail protocol (RFC08
The SMTP header 8 specified in 21) is added.

[0005] As is well known, the Internet is an open network environment, and mail is delivered to transmission destinations via a plurality of unspecified servers. Therefore, confidentiality is lower than closed heat and work. Has the disadvantage of being significantly lower. Therefore, when using the Internet for commercial purposes, some security (encryption) is required. Conventionally, generally, transmission information after the SMTP header and image data are transmitted after being subjected to predetermined encryption.

[Problems to be solved by the present invention]

[0006] However, as described above, when information having a huge data amount such as image data is transmitted, there is a drawback that it takes time to encrypt and decrypt at a transmission destination. For this reason, there has been a problem in that the user has to wait for the arrival of data for a long time, or the communication apparatus itself has a heavy load because encryption and decryption processing is required in addition to communication processing. To address this problem, for example, if a relatively weak encryption method is used, the above-described processing time can be reduced, but the transmission information 7 is extremely important, such as privacy-related information and credit card numbers. Often contains information. Therefore, security is insufficient with a weak encryption method as in this example, and a strong encryption method must still be used, and the above-mentioned problem has not been solved. The present invention minimizes the time required for encryption and decryption at a transmission destination without impairing the confidentiality of data by encryption even when transmitting information having a huge data amount such as image data. It is intended to provide an encryption method.

[0007]

In a system for transmitting transmission information to data to be transmitted and transmitting / receiving the transmission / reception between terminals connected on a network, the strength of encryption applied to the transmission information is added to the data. An encryption method for data in a network that is stronger than the encryption method, wherein the data is image data, or an encryption key for the data is inserted in the transmission information.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the concept of an embodiment of an encryption processing apparatus according to the present invention.
In the figure, reference numeral 12 denotes a serial-in / parallel-out shift register (S / P register), which holds an SMTP header 9, transmission information 10, and image data 11 arriving from a data generation unit (not shown) on the left side of the figure. It shows the state that is being done. 13a and 13b are encryption processing units, and 13a performs weak encryption and 13b performs strong encryption. Reference numeral 14 denotes a parallel-in / serial-out shift register (P / S register), which holds data encrypted by the encryption processing units 13a and 13b and sends it to the next stage as a data string. This encryption device operates as follows. The SMTP header 9 that does not require security is not subjected to encryption, and the transmission information 10 containing a lot of important information is subjected to strong encryption in the encryption processing unit 13b. After weak encryption is performed by the encryption processing unit 13a, the contents are moved from the S / P register 12 to the P / S register 14. More specifically, a strong encryption method such as elliptical encryption, RSA, DES, or a nonlinear shift register may be applied to the transmission information 10, and a weak encryption method such as a linear shift register, simple transposition, or transposition may be applied to the image data 11. By applying such an encryption method, while maintaining strong confidentiality for the transmission information 10, the processing time required for encryption is small because the data amount is relatively small, and weak encryption is also performed for the image data 11. Since only the application is performed, the processing time can be significantly reduced.

FIG. 2 is a diagram showing the concept of a decryption processing device of the encryption system according to the present invention, wherein the S / P register 21 and the P / S
Between the registers 24, a decryption processing unit that decrypts weak encryption
22a and a decryption processing unit 22b for decrypting strong encryption are arranged to decrypt the encrypted data into the original data format. It is obvious that the use of this device can greatly reduce the processing time of the decryption at the transmission destination, similarly to the above-described encryption.

[0010] As shown in FIGS. 3A and 3B, the confidentiality of the weak encryption method is improved by describing the weak encryption method decryption key to be applied to the image data in the transmission information 10. You can also. For example, even in the case of weak encryption, confidentiality as encryption can be improved by frequently and frequently changing the encryption key, that is, the decryption key for decrypting the encryption key.

Further, at this time, a strong encryption key of the transmission information 10 can be described in the SMTP header 9 and transmitted. Although the present invention has been described with reference to the case of transmitting image data via the Internet as an example, the present invention is not limited to this, and may be any other data such as moving images and audio. Needless to say, it is applicable to networks other than the Internet. In addition, although the example has been described in which the SMTP header is not encrypted at all, the encryption may be appropriately performed.

[0012]

As described above, since the present invention is configured as described above, even when transmitting information having an enormous data amount such as image data, the confidentiality of the data by encryption is maintained. This has a remarkable effect in minimizing the time required for encryption and decryption at the transmission destination without loss. In addition, it is possible to solve the problem that the user has to wait for the arrival of data for a long time, and it is possible to greatly reduce the load on the communication device itself.

[0013]

[Brief description of the drawings]

FIG. 1 is a diagram showing the concept of an embodiment of an encryption processing apparatus of an encryption system according to the present invention.

FIG. 2 is a diagram showing the concept of an embodiment of a decryption processing device of an encryption system according to the present invention.

FIGS. 3A and 3B are diagrams showing the concept of another embodiment of the encryption system according to the present invention.

FIG. 4 is a conceptual diagram showing a form of a system for transmitting facsimile information between terminals using the Internet.

FIG. 5 is a diagram showing an example of a data frame format.

[Explanation of symbols]

6, 11 ... Image data 7, 10 ... Transmission information 8, 9 ... SMTP header 12, 21, 31, 41 ... Serial-in / parallel-out shift register (S / P register) 14, 23 , 34,44 ・ ・ ・ Parallel-in / serial-out shift register (P / S register)

Claims (3)

[Claims] In a system for transmitting transmission information to data to be transmitted and transmitting and receiving the transmission information between terminals connected on a network, the strength of encryption applied to the transmission information is set to be smaller than that applied to the data. A data encryption method in a network, characterized by being strengthened. 2. The data encryption method in a network according to claim 1, wherein said data is image data. 3. The data encryption method in a network according to claim 1, wherein an encryption key of the data is inserted into the transmission information.