JPH10145351A - Encryption system for data communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the system to apply high-speed processing to encryption and decoding with one instruction during communication and to realize the encryption system with a high encryption security by allowing a transmitter side and a receiver side of a network system to possess a same initial value and a same pseudo-random number generating means, so as to produce a random number series. SOLUTION: A same pseudo-random number generating formula is possessed by both a transmitter side and a receiver side. At the start of communication, an initial value for encryption is transmitted, and a random number series is calculated. An encryption key 27 is decided, based on the random number string and a specific number of transmission information. Key information 27, and length 26 of the key are changed for each information transmission. Encryption is made for transmission information 28 by using the encryption key through exclusive OR (XOR) processing. The receiver side calculates a random number series similar to the case of the transmitter side to decide the key information. The transmitter side and the receiver side possess the same initial value and the same pseudo-random number generating formula (to obtain the same key information) and use this key information to obtain decoding information 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An information processing system for encrypting communication information between a transmitting side (server) and a receiving side (client).

[0002]

2. Description of the Related Art In the prior art, if an encryption method having a high encryption strength (such as RSA encryption or DES encryption) is employed, the encryption and decryption algorithms become complicated, and
A lot of processing time was devoted to the decoding processing time. Further, if an algorithm having a short processing time for the encryption processing is adopted, the encryption information may be easily decrypted because the length of the encryption key is constant.

[0003]

In the above-mentioned prior art, an encryption system having a high encryption strength could not be adopted in a high traffic data communication system. As an encryption method for a high traffic data communication system, a method having a weak encryption strength or a method having a strong encryption strength must be adopted while sacrificing the response time of data communication.

In particular, the Internet WWW (World
Wide Web) can transmit and receive information shown on a page described in HTML. Recently, information on a megabyte basis has been frequently exchanged. However, most information is not encrypted. Sent or received
Or, in most cases, transmission and reception are performed by weak encryption.

[0005] It is an object of the present invention to realize an encryption method in which encryption processing is suppressed to a level that hardly affects the response time of data communication and encryption strength is high.

[0006]

FIG. 1 is a diagram showing the concept of the present invention.

[0007] First, the same pseudorandom number generation formula is owned by both the transmitting side and the receiving side. At the start of communication, first, an initial value of encryption is transmitted, and a random number sequence is generated on the transmission side and the reception side. The transmitting side calculates a random number sequence from the random number sequence and the unique number of the transmission information, and determines key information. The key information changes the key content and key length every time information is transmitted in order to increase the encryption strength.

The transmission information body is encrypted by using a simple instruction group using the encryption key. Here, the simple instruction group is an instruction group composed of one machine language instruction such as exclusive OR (XOR) or a small number of machine language instructions.

On the receiving side, a random number sequence is generated from the initial value of encryption and the formula of pseudorandom number generation, and key information is determined from the unique number of the received information and the random number sequence, as in the transmitting side. here,
Since the pseudorandom number generation formula and the encryption initial value are shared before the start of communication, the same random number sequence can be obtained, and therefore the same key information can be obtained. Using the key information thus obtained, a group of instructions for decryption (inverse conversion of a group of instructions for encryption)
To perform decryption.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a diagram showing a processing procedure of the present invention.

The same pseudo-random number generation formula 10 and pseudo-random number generation formula 20 are stored in a storage device on the client side and the server side, respectively.

An M-sequence random number sequence is used as a formula for pseudorandom number generation, and a three-nominal expression capable of generating random numbers by one exclusive OR is selected as a characteristic polynomial. (For example, f
Such as ^{(x) = 1 + x 32} + x 521. Also, the number of bits of one value of the random number sequence is set to 32 bits.

At the start of data communication, the server determines an initial value 21 and an initial value 22 and transmits them to the client. (Initial synchronization) The client stores these as an initial value 11 and an initial value 12. Initial value 2
1 and the initial value 22 are any positive odd numbers that can be represented by 32 bits. WWW (World Wide We
In the case of the information exchange in b), this initial synchronization is performed when the corresponding HTML page is loaded. On the client side, based on the initial value 11 and the initial value 12, a random number sequence 13 and a random number sequence 14 are created from the characteristic polynomial of the M-sequence random number. Similarly, the server creates a random number sequence 23 and a random number sequence 24. Since the initial values match, the random number sequence 13 and the random number sequence 2
3. The random number sequence 14 and the random number sequence 24 match.

[0015] Upon receiving the transmission request from the client, the server starts the process of creating encryption key information. The length 26 of the encryption key is created using the random number sequence 23 and the transmission information unique number 25. The length 26 of the encryption key is created by a simple calculation based on the random number sequence 23 in order to shorten the creation process. For example, the 25th unique number from the top of the random number sequence 23 is used.

Next, an encryption key 27 is created using the random number sequence 24 and the transmission information unique number 25. This encryption key 27
Creates the same number as the value of the encryption key length 26.

The length 2 of the encryption key determined by this method
6 and the encryption key 27, the transmission information 28 is encrypted.

At the time of encryption, encryption is performed using only exclusive OR (XOR) every 4 bytes (= 32 bits), and machine instructions used for encryption are performed in the shortest (one instruction). This process uses keys in order from the top,
The length of the encryption key is 26 times, and when the key is used up to the end, the key is reused and encrypted from the beginning. Thus, the encrypted information 29 is obtained.

The server transmits the transmission information unique number 25 and the encryption information 29 to the client.

In the decryption processing, the client performs the same operation.

The client first creates a length 16 of the encryption key using the random number sequence 13 and the transmission information unique number 15, and uses the random number sequence 14 and the transmission information unique number 15
An encryption key 175 is obtained.

According to this method, the same encryption key length 26 and encryption key 27 determined by the server can be obtained.

In decoding, decoding is performed by using an exclusive OR (XOR) for every 4 bytes, and decoding information 19 can be obtained. The content of the decryption information 19 matches the content of the transmission information 28.

[0024]

According to the present invention, the following advantages can be obtained in encrypted data communication.

(1) Since the length of the key is changed for each encryption communication, it is difficult to decipher the key.

In the conventional method, in the high-speed encryption processing, since the length of the key is constant, the key is easily decrypted when a pair of a communication message and its original text is obtained. In the method of the present invention,
Even if one set of a message and an original is obtained, it is extremely difficult to specify the initial value used at that time.

(2) High-speed encryption and decryption In the conventional encryption method with a high encryption strength, bit shift and bit inversion are repeated for each conversion unit (about 8 bytes), and processing of 10 or more machine language instructions is performed. However, in the method of the present invention, encryption and decryption are performed with one machine language instruction for every four bytes of a message, so that high-speed processing is possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing the concept of the present invention.

FIG. 2 is a diagram showing a processing procedure of the present invention.

[Explanation of symbols]

10: pseudo-random number generation formula (client side), 11: initial value for generating random number sequence 13, 12: random number sequence 14
, 13... Length of the encryption key 16
, A random number sequence for obtaining the encryption key 17, 15 a transmission information unique number (client side),
16: length of encryption key (client side), 17: encryption key (client side), 19: decryption information,
20: pseudo-random number generation formula (server side), 21: random number sequence 2
3, an initial value for generating a random number sequence 24, a random number sequence for obtaining an encryption key length 26, a random number sequence for obtaining an encryption key 27 , 25 ... transmission information unique number (server side), 26 ... length of encryption key (server side), 27 ... encryption key (server side), 28 ... transmission information,
29. Encrypted information.

Claims (2)

[Claims] 1. A transmitting side and a receiving side of a network system for transmitting and receiving information using a communication line possess the same initial value and the same pseudo-random number generating means to generate a random number sequence, thereby enabling communication during communication. One encryption and decryption process
An encryption method that is processed at high speed with instructions or several instructions. 2. The Internet WWW (world W)
The transmitting side (server) and the receiving side (client) of the system for transmitting and receiving information using ide Web) have the same initial value and the same pseudo-random number generating means and generate a random number sequence, thereby performing communication. An encryption method in which the encryption and decryption processing of the above is performed at high speed with one or several instructions.