CN101001142A

CN101001142A - Encipher-decipher method based on iterative random number generator

Info

Publication number: CN101001142A
Application number: CN 200710062792
Authority: CN
Inventors: 张建华
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-01-17
Filing date: 2007-01-17
Publication date: 2007-07-18

Abstract

This invention discloses a ciphering-deciphering method based on an iterative random number generator, which takes the random binary bit flow generated by an iterative random generator as the cryptographic flow, and a sending party carries out XOR logic operation to cleartext data and said cryptographic key flow to generate cryptographic data and sends them to the receiving party, which carries out XOR logic operation to them to recover them to cleartext data.

Description

A kind of encipher-decipher method based on iterative random number generator

Technical field

The present invention relates to field of information security technology, relate in particular to a kind of encrypting and decrypting method that adopts iterative random number generator.

Background technology

Along with the fast development of computer technology and information technology, various data messages need transmit between different user.When this form offers convenience to people, fail safe hidden danger also occurred, a lot of data messages have confidentiality, and often requirement can not and be distorted by desultory reading, therefore just needs to guarantee the fail safe of sensitive information.People mainly utilize cryptographic technique to control the visit of disabled user to sensitive information at present, for example utilize various key mechanisms to file encryption, or utilize password authentification to verify user's identity, thereby prevent disabled user's access file.Encipher-decipher method is one of important technology of electronic security(ELSEC) and communication device, is widely used in fields such as bank, commerce, military affairs, automobile.

Present encipher-decipher method is various, but to reusing the encipher-decipher method of short message, remains the difficult problem in this field.Existing DES Cipher, IDEA IDEA etc. are the enciphering and deciphering algorithms of comparative maturity.But these ripe algorithms are more complicated all, realizes the cost height, not too suitable low-cost, the fairly simple application of hardware resource.

Summary of the invention

The present invention is directed to the problem that encipher-decipher method exists in the prior art, proposed a kind of enciphering and deciphering algorithm based on iterative random number generator.

Encipher-decipher method based on iterative random number generator of the present invention, be that the random binary bit stream that generates with iterative random number generator is as key stream, transmit leg is by carrying out XOR computing generation encrypt data with clear data and described key stream, send to the recipient, the recipient carries out the XOR computing with described encrypt data and described key stream, is reduced into clear data.

The next random number of described iterative random number generator is produced by interative computation by current random number.Existing tandom number generator can adopt the congruence method tandom number generator, constitute tandom number generator etc. with linear feedback shift register mostly based on iterative algorithm.

Described transmit leg and recipient be the iteration function, the step number and the current random number of iteration of known described iterative random number generator.

When described transmit leg is encrypted clear data, calculate next random number, carry out XOR, obtain encrypt data with described clear data with current random number and iteration function.

When described recipient deciphers encrypt data, calculate next random number, carry out XOR, obtain clear data with described encrypt data with current random number and iteration function.

Compared with prior art, the invention has the beneficial effects as follows: the enciphering and deciphering algorithm based on iterative random number generator provided by the invention, its algorithm is simple, is convenient to realize, and is not high to hardware requirement, economical and practical.

Description of drawings

Fig. 1 is the linear feedback shift register schematic diagram;

Fig. 2 is based on the encryption flow figure of iterative random number generator;

Fig. 3 is based on the deciphering flow chart of iterative random number generator.

Embodiment

Now reaching embodiment in conjunction with the accompanying drawings is described in further detail the present invention.

Encipher-decipher method based on iterative random number generator of the present invention, its principle is that the random binary bit stream that generates with iterative random number generator is as key stream, transmit leg is by carrying out XOR computing generation encrypt data with clear data and described key stream, send to the recipient, the recipient carries out the XOR computing with encrypt data and described key stream, be reduced into clear data, finish the encryption and decryption process.

In the present embodiment, iterative random number generator is made of linear feedback shift register, and its operation principle as shown in Figure 1.With reference to figure 1: this is one the 32 (shift registers of D32～D1), current 32 random number R (k) are packed among D32～D1, state d31～d1 of D31～D1 moves to left one, deliver among D32～D2 respectively, this moment, the new state of D1 was decided by feedback function F, feedback function f is: d0=d32+d7+d5+d3+d2+d1, the D32～D1 after the displacement are exactly new random number R (k+1).The rest may be inferred, and R (k) is R (k+n) through the random number that n displacement produces.Come encrypting plaintext data and decrypting ciphertext data with this random number as key stream.

Fig. 2 and Fig. 3 are based on the encryption flow figure and the deciphering flow chart of above-mentioned 32 bit linear feedback shift registers respectively.Represent to form the linear feedback shift register of random number key stream R with iteration function f, wherein k is 0,1,2 ..., then the relation of random number key stream R and iteration function f can be expressed as:

R(k+1)＝f[R(k)]

The prerequisite of this method is step number n (n=0,1,2 that transmit leg and recipient need to know iteration function f and iteration ...).Ciphering process is with reference to figure 2, and transmit leg 201 carries out XOR 204 with clear data P202 and random number key stream 203, forms encrypt data M205, sends to recipient 206.If wherein random number key stream 203 is R (k+n), then clear data P is encrypted as encrypt data M by random number key stream 203, and encryption method is:

Encrypt data M=P XOR R (k+n)

Wherein XOR represents XOR.So, be exactly [R (k), M] to the data that recipient 206 sends this moment.

Corresponding decrypting process is with reference to figure 3, recipient 301 known R (k) and iteration function f, and with R (k+1)=f[R (k)] calculate random number key stream 303R (k+n), carry out XOR 304 with enciphered data M302:

Clear data P=R (k+n) XOR M

Wherein XOR represents XOR, obtains clear data P.

In some cases, transmit leg can also directly send a random number R (k) and inquire that to the recipient recipient calculates R (k+n) with known R (k) and iteration function f, and carries out XOR with R (k+n) and clear data P, obtains encrypt data M:

M＝P?XOR?R(k+n)

Then recipient's transmission reply data is encrypt data M.Transmit leg calculates R (k+n) with same R (k) and iteration function f, carries out XOR with the encrypt data M that receives again, the clear data P that obtains reducing:

P＝R(k+n)XOR?M

The above execution mode only is the preferred embodiments of the present invention; the invention is not restricted to the foregoing description; for persons skilled in the art; the any conspicuous change of under the prerequisite that does not deviate from the principle of the invention it being done all belongs to the protection range of design of the present invention and claims.

Claims

1. encipher-decipher method based on iterative random number generator, it is characterized in that: the random binary bit stream that generates with iterative random number generator is as key stream, transmit leg is by carrying out XOR computing generation encrypt data with clear data and described key stream, send to the recipient, the recipient carries out the XOR computing with described encrypt data and described key stream, is reduced into clear data.

2. the encipher-decipher method based on iterative random number generator according to claim 1 is characterized in that: the next random number of described iterative random number generator is produced by interative computation by current random number.

3. the encipher-decipher method based on iterative random number generator according to claim 1 is characterized in that: described transmit leg and recipient be the iteration function, the step number and the current random number of iteration of known described iterative random number generator.

4. the encipher-decipher method based on iterative random number generator according to claim 1, it is characterized in that: when described transmit leg is encrypted clear data, calculate next random number with current random number and iteration function, carry out XOR, obtain encrypt data with described clear data.

5. the encipher-decipher method based on iterative random number generator according to claim 1, it is characterized in that: when described recipient deciphers encrypt data, calculate next random number with current random number and iteration function, carry out XOR, obtain clear data with described encrypt data.

6. the encipher-decipher method based on iterative random number generator according to claim 1 is characterized in that: described iterative random number generator is to constitute tandom number generator by the line feedback shift register.