JPH04140947A - Random number generator in coder - Google Patents

Abstract

PURPOSE:To simply build up a transmission system as a ciphering transmission system by forming the transmission system to be a system simply possible for ciphering processing and allowing one equipment to implement ciphering processing and a MODEM function. CONSTITUTION:Scramble coding by a pseudo random number is generated by generating a pseudo random number series and EXORing (exclusive OR) the series with a data series. Moreover, random number character conversion ciphering processing one of ciphering, is ciphering processing to be generated by EXORing the pseudo random number series with a data. The pseudo random number generator is made up of a shift register and a tap string. Moreover, a MODEM at a communication side generates plural kinds of pseudo random numbers with different generation polynomial and a receiver side has one of the generation polynomial in the MODEM as a ciphering processing key specific to each terminal equipment and decodes the data so as to attain ciphering processing communication using a common key.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of application of m-collection] The present invention relates to a random number generation device in an encoding device used for communication, etc.

[Prior Art] When communicating via a transmission path, encoding as shown in FIG. 4 is known. Error correction coding (ECC) is used to recover errors that occur when the error rate of a transmission path is poor. Additionally, transmission line encoding (modem) is used in many systems to facilitate timing extraction.

[Problems to be Solved by the Invention] However, conventional transmission systems have not given much consideration to encryption, and many have not included an encoding device. Further, even if an encryption device was available, it was performed separately from other encodings, and a device was required for each encoding.

[Means for solving the problem] Therefore, we have developed a transmission line code that eliminates the above-mentioned drawbacks, turns a transmission system that did not consider encryption into a system that can easily encrypt, and allows encryption and modem to be performed in one device. We propose a method and transmission system for this purpose.

[Embodiment] Scramble encoding of data using pseudo-random numbers is one type of transmission line encoding, and is generated by generating a pseudo-random number sequence and performing EXOR (exclusive OR) with the data sequence. This encoding is characterized by the fact that there is no increase in the circuit configuration and transmission line code speed.

Furthermore, random number substitution encryption, which is one type of encryption, is also an encryption that is performed by EXORing data with a pseudo-random number sequence. This pseudo-random number generator can be configured with a shift I register and a tap sequence j' as shown in Fig. In the case of encryption, each device has a different tap using the pseudorandom number generator polynomial as the encryption key.In this embodiment, the modem on the communication side generates multiple types of pseudorandom numbers with different generator polynomials. By generating and decrypting the L file of the Ushinarita q-style L file in the modem with an encryption key unique to each terminal, the receiving side decrypts the L file in the modem as shown in Figure 2. 1. Construct a transmission system capable of i'T encrypted communication using keys. ．．
．． ．． ．． ．． fI・0 In this embodiment, the modem on the receiving side is composed of 64 pseudo-random number generators with a fixed tap sequence based on the encryption key i.On the other hand, the pseudo-random number generator on the sending side , the generator generates multiple types of pseudo-random numbers with different generator polynomials.

Multiple types of pseudorandom numbers with different generating polynomials are shown in Figure 1.
J is generated by a pseudo-random number generator ε having a tap array composed of a ROM (read-only memory) controlled by a generator polynomial. This ROM receives the output from the shift register.
R represents the type of bit and pseudo-random number generating polynomial (encryption key) and has an input address of f and an output of 1 bit.
OM"r can be configured. The ROM stores a plurality of generating polynomials I2.1, and generates a generating polynomial according to the input encryption key.

On the transmission side, the destination (z) and the corresponding encryption key are sent to the RO shown in the first diagram.
M is given to generate a pseudo-random number.

On the other hand, on the receiving side, a pseudo random number unique to the receiving side is demodulated by -4.

"Effect of the invention] As described above, the modem can be easily encoded into an encryption device.

The effects of the present invention are that since the modem is used as a secret filter, there is no increase in equipment, and since it is only necessary to change the configuration of the tap array in the modem, there is no need to change the system method such as transmission line encoding. Nor.

Although the present invention has a problem in that the encryption strength is weak, the present invention allows a transmission system in which encryption has not been considered until now to be easily configured and used as an encrypted transmission system with almost no changes. .

[Brief explanation of the drawing]

Figure 11 is a circuit diagram of a pseudo-random number generator that realizes transmission line encoding according to an embodiment of the present invention, and Figure 2 is a system diagram of transmission line encoding that combines a cipher and a modem according to an embodiment of the present invention. FIG. 3 is a circuit diagram of a conventional pseudorandom number generator, and FIG. 4 is a diagram of a conventional encoding system for a transmission path. Figure 1 Shift register Figure 2 Key

Claims (2)

[Claims] (1) Random numbers in an encoding device characterized by having a generating means for generating multiple types of pseudo-random numbers with different generating polynomials, and means for taking an exclusive OR of data and the pseudo-random numbers generated by the generating means. Generator. (2) In the random number generation device in the encoding device according to claim 1, the generation means includes an n-stage shift register, an n-stage tap array, and an output of the shift register and a pseudo-random number generating polynomial. A random number generator in an encoding device, characterized by having a controlled memory.