Data cipher system in network

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to data transmission in a network, particularly an image data encryption method.

【0002】

[Conventional technology]

In recent years, a wide area network such as the Internet has been developed, and data transmission using this has become common. FIG. 4 is a conceptual diagram showing a form of a facsimile information transmission system between terminals using the Internet.

【0003】

The terminal 1 transmits the data (text, image) prepared in advance to the fax device 5 via the Internet 2 and the other terminal 3 or the gateway 4.

【0004】

Terminal 1 prepares data in the frame format as shown in Fig. 5. Immediately before the image data 6 to be transmitted, transmission information 7 describing the transmission destination or source information (FAX number, password, user name, etc.) is added, and immediately before that, it is specified by the Internet mail protocol (RFC0821). Attach the SMTP header 8 that has been created.

【0005】

As is well known, the Internet is an open network environment, and mail is delivered to the transmission destination via multiple unspecified servers, so confidentiality is significantly lower than closed heat and work. There is a drawback. Therefore, when using the Internet for commercial purposes, some kind of security (encryption) is required. Conventionally, in general, transmission information and image data after the SMTP header are transmitted after being subjected to predetermined encryption.

PROBLEM TO BE SOLVED: To solve a problem of the present invention.

【0006】

However, as described above, when transmitting information presenting an enormous amount of data such as image data, there is a drawback that it takes time to encrypt and decrypt at the transmission destination. For this reason, there has been a problem that the user has to wait for the arrival of data for a long time, or the communication device itself is heavily burdened because encryption and decryption processing are required in addition to the communication processing. In order to deal with this problem, for example, a relatively weak encryption method can be used to shorten the above-mentioned processing time, but the transmission information 7 is extremely important such as privacy-related information and credit card numbers. Often contains information. Therefore, since the security is insufficient with the weak encryption method as in this example, it is still necessary to use the strong encryption method, and the above-mentioned problems have not been solved yet. The present invention limits the time required for encryption and decryption at the transmission destination without impairing the confidentiality of the data by encryption even when transmitting information presenting an enormous amount of data such as image data. The purpose is to provide an encryption method.

【0007】

[Means for solving problems]

In a system in which transmission information is added to data to be transmitted and the transmission information is transmitted and received between terminals connected on the network, the data in the network in which the encryption strength applied to the transmission information is stronger than that applied to the data. In particular, the data is image data, or the encryption key of the data is inserted into the transmission information.

【0008】

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a drawing showing the concept of an embodiment of an encryption processing device of an encryption method according to the present invention. In the figure, 12 is a serial-in / parallel-outshift register (S / P register), which holds the SMTP header 9, the transmission information 10, and the image data 11 that arrived from the data generator (not shown) on the left side of the figure. It shows the state that is being done. 13a and 13b are encryption processing units, 13a is for weak encryption, and 13b is for strong encryption. Reference numeral 14 denotes a parallel-in / serial-outshift register (P / S register), which holds the 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 left as it is without encryption, the transmission information 10 that contains a lot of important information is strongly encrypted by the encryption processing unit 13b, and the image data 11 is After performing weak encryption in the encryption processing unit 13a, the contents are moved from the S / P register 12 to the P / S register 14. Specifically, Elliptic Curve Cryptography, RSA, A strong encryption method such as DES or a non-linear shift resistor may be applied to the transmission information 10, and a weak encryption method such as a linear shift resistor, a simple transposition, or a replacement 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 short because the amount of data is relatively small, and weak encryption is also applied to the image data 11. It is possible to significantly reduce the processing time because it is only applied.

【0009】

FIG. 2 is a drawing showing the concept of a decryption processing device of an encryption method according to the present invention, in which a decryption processing unit 22a for decrypting a weak encryption is formed between the S / P register 21 and the P / S register 24. , A decryption processing unit 22b that decrypts strong encryption is arranged, and the encrypted data is decrypted to the original data format. It is self-evident that by using this device, it is possible to significantly reduce the processing time of the decryption at the transmission destination as well as the above-mentioned encryption.

【0010】

Further, as shown in FIGS. 3 (a) and 3 (b), the confidentiality of the weak encryption method can be enhanced by describing the decryption key of the weak encryption method applied to the image data in the transmission information 10. .. For example, even with weak encryption, the confidentiality of the encryption can be enhanced by changing the encryption key, that is, the decryption key for decrypting the encryption key at random and frequently.

【0011】

Further, at this time, the strong encryption encryption key of the transmission information 10 can be described in the SMTP header 9 and transmitted. Although the present invention has been described above by taking the case where image data is transmitted via the Internet as an example, the present invention is not limited to this, and any other data such as moving images and audio can be used. It is not necessary to explain that it is applicable to networks other than the Internet. Further, although an example in which no encryption is applied to the SMTP header is shown, encryption may be appropriately applied.

【0012】

[Effect of the invention]

As described above, since the present invention is configured as described above, even when transmitting information presenting a huge amount of data such as image data, the data is encrypted without impairing the confidentiality of the data by encryption. And, it has a remarkable effect in limiting the time required for decoding at the transmission destination. In addition, problems such as the user having to wait for the arrival of data for a long time can be solved, and the burden on the communication device itself can be significantly reduced.

【0013】

[Simple explanation of drawings]

[Figure 1]

The drawing which shows the concept of one Example of the encryption processing apparatus of the encryption method which concerns on this invention.

[Figure 2]

The drawing which shows the concept of one Example of the decryption processing apparatus of the encryption system which concerns on this invention.

[Fig. 3]

(a) and (b) are drawings showing the concept of another embodiment of the encryption method according to the present invention.

[Fig. 4]

A conceptual diagram showing a form of a facsimile information transmission system between terminals using the Internet.

[Fig. 5]

The figure which shows the example of the frame format of data.

[Explanation of symbols]

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