CN115459906A - A parallelization and anti-dynamic degradation method for key stream generator - Google Patents

Abstract

The invention discloses a method for parallelizing and resisting dynamic degradation of a key stream generator, which comprises the following steps: s1, receiving an initial key; s2, initializing all the key stream generators by adopting a preset key stream generator initialization method on the basis of an initial key simultaneously or step by step, and parallelly generating key streams by adopting a preset parallel working method for the initialized key stream generators; and S3, combining the key stream generated by the key stream generator by adopting a preset combination method to generate a final key stream for encryption and decryption. And S4, after the key stream generator iterates to the specified iteration upper limit, re-initializing the key stream generator by adopting a preset key stream generator re-initialization method. The method is based on the parallel calculation of multiple key stream generators, the speed of generating the key stream by the stream cipher is increased, and the possibility of dynamic degradation is reduced by utilizing the automatic initialization of the key stream generators.

Description

A parallelization and anti-dynamic degradation method for key stream generator

technical field

The invention relates to the technical field of cryptography, in particular to a parallelization and dynamic degradation resistance method of a key stream generator.

Background technique

Stream cipher (stream cipher) belongs to the symmetric cryptosystem, which uses the same or equivalent key to realize encryption and decryption. Because of its advantages of easy hardware implementation, simple encryption and decryption, and low probability of error propagation, it has a large number of applications in the field of secure communication. application. The stream cipher takes a set of keys as input, initializes the key stream generator to generate a set of key streams, and then uses the key stream to perform operations with plaintext or ciphertext according to certain rules to realize encryption of plaintext or encryption of ciphertext. decrypt.

The key stream generator is the core component of the stream cipher. It completes the initialization with the input key, and iterates repeatedly according to certain rules to generate the key stream. Because each iteration is related to the key or the result of the previous iteration, the iterations can only be completed sequentially to generate the key stream. This severely limits the speed at which the key stream generator can generate key streams, which cannot meet the needs of high-speed encryption and decryption application scenarios.

In addition, no matter how good the statistical properties of the key stream generator are in theory, if it is implemented on limited-precision hardware, the problem of dynamical degradation will occur. It may weaken the statistical properties of the key stream, thereby reducing system security.

Contents of the invention

In order to overcome the speed and dynamic degradation problems of the key stream generator, the present invention provides a method for parallelizing the key stream generator and anti-dynamic degradation, which can effectively increase the key stream generation speed and alleviate the dynamic degradation problem.

In order to achieve the above object, a kind of keystream generator parallelization and anti-dynamic degradation method adopted by the present invention,

S1. Receive the initial key;

S2. Based on the initial key, use the preset key stream generator initialization method on all key stream generators to initialize the key stream generators at the same time or step by step. After initialization, the key stream generators use the preset parallel working method , to generate the keystream in parallel;

S3. Combining the key stream generated by the key stream generator using a preset combination method to generate a final key stream for encryption and decryption.

S4. After the key stream generator iterates to the specified iteration upper limit, the key stream generator is reinitialized by using a preset key stream generator reinitialization method.

Further, the initial key has at least one key, one key is used to complete the initialization of one key stream generator, and one key consists of at least one parameter.

Further, the key stream generator uses the mapping iteration method to generate iteration results, and the specific process is as follows:

The map is denoted as F, the key is denoted as k ₀ , and the key is substituted into the map to complete the initialization of the key stream generator: F(k ₀ )=z ₁ , where z ₁ is called the iteration result;

Use z ₁ to replace one or more parameters in k ₀ to get k ₁ , and substitute k ₁ into the map: F(k ₁ )=z ₂ , and iterate according to F(k _i-1 )= _zi to generate a Group iteration results (keystream) z ₁ ,...,z _n .

Further, remember that the total number of keystream generators is M, then

At the same time in the S2, the key stream generator is initialized, including:

Initializing M key stream generators based on the initial key, where the number of keys in the initial key is M;

The steps in S2 initialize the key stream generator, including:

First use the initial key to initialize K key stream generators, the number of keys in the initial key is K, where 1≤K≤M, and then use the iteration results of K key stream generators according to k ₀ The structure constructs MK keys, and completes the initialization of the remaining key stream generators.

Further, the preset parallel working method includes:

In the case of initializing the key stream generators in S2 at the same time: all key stream generators iterate in parallel, and the generated iteration results are combined using a preset combination method to generate the final key stream for encryption and decryption;

In the case of step-by-step initialization of key stream generators in S2: K (1≤K≤M) key stream generators are used to generate keys, where M is the total number of key stream generators, and the remaining The M-K key stream generators are initialized, and the M-K key stream generators iterate in parallel, and the generated iteration results are combined using a preset combination method to generate the final key stream for encryption and decryption.

Further, the preset combination method includes sequential arrangement, alternating arrangement and scrambling arrangement.

Further, in said S4, the preset key stream generator reinitialization method includes:

Select the corresponding selected iteration result from the key stream generator's own iteration result to construct a new key, substitute the new key into the map, and re-initialize the map;

and / or

Select the corresponding iterative result from the iterative results of other key stream generators to construct a new key, substitute the new key into the map, and reinitialize the map.

A key stream generator parallelization and anti-dynamic degradation method of the present invention has the following beneficial effects:

According to the parallelization and anti-dynamic degradation method of a key stream generator in the present invention, by setting multiple key stream generators, all key stream generators are directly initialized with the key input by the user or one or more key stream generators are initialized first One key stream generator, and then use the generated key stream to initialize other key stream generators, so that multiple key stream generators can work in parallel and generate key streams at the same time, effectively improving the key stream generation speed.

The above method is applicable to different software and hardware platforms and is easy to implement. For example, a speed increase of more than 4 times can be achieved on the tiny embedded system JetsonXavier NX (6-core NVIDIA Carmel ARM v8.2 64-bit CPU). Using a more powerful CPU can achieve higher throughput, and can take advantage of heterogeneous computing, such as using a GPU to further improve performance. In addition, all key stream generators automatically use the generated key stream to re-initialize after a certain number of iterations, which greatly reduces the possibility of key stream generators falling into a loop and experiencing dynamic degradation.

With reference to the following descriptions and drawings, specific embodiments of the present invention are disclosed in detail, and the manner in which the principle of the present invention can be adopted is indicated. It should be understood that the embodiments of the present invention are not limited thereby in scope. Embodiments of the present invention encompass many changes, modifications and equivalents within the spirit and scope of the appended claims.

Description of drawings

Fig. 1 is a schematic flow diagram of a key stream generator parallelization and anti-dynamic degradation method;

FIG. 2 is a schematic flow diagram of stream cipher decryption in an embodiment of the present invention;

Fig. 3 is a working block diagram of a kind of keystream generator parallelization and anti-dynamic degradation method;

Fig. 4 is the working block diagram of a kind of keystream generator parallelization and anti-dynamic degeneration method based on chaotic mapping algorithm;

Fig. 5 is a working block diagram of the method for updating the chaotic map in the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described here are only used to explain the present invention, and are not intended to limit the scope of the present invention.

It should be noted that when an element is said to be "disposed on, provided with" another element, it may be directly on the other element or there may also be an intermediate element. A component, it can be directly connected to another component or there may be an intermediate component at the same time. "Fixed connection" means fixed connection. There are many ways of fixed connection, which are not within the scope of protection of this article. The term used in this article "Vertical", "horizontal", "left", "right" and similar expressions are for the purpose of illustration only and do not represent the only embodiment.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification herein are only for the purpose of describing specific embodiments, not In order to limit the present invention, the term "and/or" used herein includes any and all combinations of one or more related listed items;

Please refer to the accompanying drawings 1-5 of the description to illustrate the embodiment for implementing the present invention. In the stream cipher working process, a kind of key stream generator parallelization and anti-dynamic degradation method is applied. Generally speaking, the stream cipher Generally, a pseudo-random number generator is initialized with a set of keys, and then the bit string user data encryption is generated in batches. Specifically,

A stream cipher system consists of a six-tuple (M1, C1, K1, Z, E, D) and function g, where M1 is the plaintext space, C1 is the ciphertext space, K1 is all possible key sets, and Z is The set of all possible keystream characters such that:

Function g is a key stream generator, which takes key k∈K1 as input, completes initialization, and then outputs key stream z=z ₁ , z ₂ ,...z _n (z _i ∈ Z).

For any z∈Z, there exists an encryption function e _z ∈E and a corresponding decryption function d _z ∈D. And for each e _z :M1→C 1,d _z :C1→M 1, for any plaintext m∈M1, d _z (e _z (m1))=m1.

As shown in Figure 2, the process of stream cipher encryption and decryption is generally that user A inputs key k1 to initialize the key stream generator, and the key stream generator generates key stream z in batches and encrypts plaintext m1 to generate ciphertext c1. transmitted to user B. User B uses the same key k1 to initialize the key stream generator to generate a key stream z, and uses the key stream z to decrypt the ciphertext c1 to obtain the plaintext m1.

The general working process of the core key stream generator of the stream cipher is shown in Figure 2. The key stream generator is initialized with a set of inputs. After initialization, after some processing, the first iteration result z ₁ is generated, and then according to z ₁ , and produce the result of the second iteration. The working process of existing key stream generators may be slightly different, but they basically continue to iteratively generate key streams based on the previous iteration results. The correlation between the iterative results causes the key stream generator to work only sequentially, generating iterative results in turn to form a key stream, which is difficult to work in parallel and cannot meet the needs of high-speed encryption and decryption application scenarios.

In order to improve the generation speed of the cipher stream, an embodiment of a key stream generator parallelization and anti-dynamic degradation method is shown in Fig. 1-Fig. 3, in this embodiment, the following implementation steps are included:

A keystream generator parallelization and dynamic degradation resistance method, comprising:

S1. Receive the initial key input by the user; in this step, the number of the above-mentioned initial key is at least one;

S2. Based on the initial key, use a preset key sequence generation method on all cipher stream generators to generate step by step or simultaneously the key sequences corresponding to the cipher stream generators;

In this step, the key sequence corresponding to the cipher stream generator is generated step by step on all cipher stream generators using the preset key sequence generation method based on the initial key, including:

When the number of initial keys input by the user is K, based on K cipher stream generators as the first cipher stream generators, the preset key sequence generation method is used to generate the first key corresponding to each first cipher stream generator. Key sequence, 1≤K<M, where M is the total number of cipher stream generators;

Based on the remaining M-K cipher stream generators as the second cipher stream generator, the second cipher stream generator is based on the data in the first key sequence in pairs as control parameters and initial conditions, using the preset key sequence generation method to generate A second key sequence corresponding to each second cipher stream generator.

Based on the initial key, use the preset key sequence generation method on all cipher stream generators to simultaneously generate the key sequence of the corresponding cipher stream generator, including:

When the number of initial keys input by the user is M, based on the input of each cipher stream generator in each initial key, the encryption corresponding to each cipher stream generator is generated by using the preset key sequence generation method key sequence, where M is the total number of cipher stream generators.

In this step S2, when the key stream generator iterates for a certain number of times, it may generate the same or very similar iterative results as the previous iteration results, which may cause the iteration to fall into a loop and repeatedly generate a set of the same or similar key streams, weakening Statistical features of key streams reduce system security.

Therefore, in the present invention, when the chaotic mapping algorithm in the cipher stream generator reaches the preset maximum number of iterations, the first anti-dynamic degradation method or the second anti-dynamic degradation method is used to initialize the control parameters and initial conditions of the chaotic mapping algorithm to update the chaotic mapping algorithm;

The first anti-dynamic degradation method includes:

After the cipher stream generator itself reaches the maximum number of iterations, it iterates twice, and uses the two iteration results as control parameters and initial conditions to reinitialize itself, or directly based on the two keys in the key sequence generated by the cipher stream generator itself. parameters as control parameters and initial conditions to reinitialize itself;

The second anti-dynamic degradation method includes: using the cipher stream generator that has not reached the maximum number of iterations among the M cipher stream generators to continue to perform chaos map iterations, based on the iteration of the cipher stream generator that has not reached the maximum number of iterations The result is used as new control parameters and initial conditions of the cipher stream generator that has reached the maximum number of iterations, realizing the reinitialization of the cipher stream generator that has reached the maximum number of iterations.

S3. Combining the key sequence based on each cipher stream generator using a preset combination method to obtain a key stream for encryption and decryption.

In this step, there are two ways to obtain the cipher stream used for encryption and decryption.

The first way to obtain the cipher stream used for encryption and decryption: this method corresponds to the method of generating the key sequence of the corresponding cipher stream generator step by step using the preset key sequence generation method on all cipher stream generators based on the initial key , in the step S3 after this method, based on all the second key sequences, they are combined using a preset combination method to obtain the key stream for encryption and decryption. Correspondingly,

The first way to obtain the cipher stream used for encryption and decryption: this method corresponds to the method of synchronously generating the key sequence of the corresponding cipher stream generator on all cipher stream generators using the preset key sequence generation method based on the initial key, In step S3 following this method, based on M key sequences generated by M cipher stream generators, they are combined using a preset combination method to obtain key streams for encryption and decryption.

As a further optimization of the above solution, the preset combination methods include sequential arrangement, alternate arrangement and scrambling arrangement.

As shown in Figure 4 and Figure 5, further discussion on the parallelization and anti-dynamic degradation method of the above-mentioned key stream generator:

The method for generating the preset key sequence adopts a chaotic mapping algorithm, which comprises the following steps:

Based on one parameter in the initial key is recorded as the control parameter p ∈ (0,0.α), and the other parameter is recorded as the initial condition x ₀ ∈ [0, β], based on p and x ₀ perform chaotic mapping to generate iteration results

The chaotic mapping algorithm is:

时，将

作为p值。In the iterative process of the chaotic mapping algorithm, the iterative result

when, will

as a p-value.

The following is a preferred embodiment of a key stream generator parallelization and anti-dynamic degradation method based on chaotic mapping. In this preferred embodiment, the number of the above-mentioned initial keys is selected as 1, and the two parameters of the initial key generation are respectively p∈(0,0.5), x ₀ ∈[0,1], p is the control parameter, x is the initial condition,. Substituting two parameters into F(x ₀ ,p) can generate the iteration result x ₁ , and then substituting x ₁ into F(x ₁ ,p) can generate the iteration result x ₂ , and so on, repeat iterations to generate a set of iteration results{ x ₁ ,…,x _n }, the generated iteration result can be used for encryption and decryption.

It can be seen from the above process that the generation of each iteration result is related to the previous iteration process, and must be executed sequentially, and cannot be processed in parallel. Based on the present invention, the following scheme can be used to realize parallelization and improve the generation speed of iteration results:

Referring to Figure 4, set parameters p ∈ (0,0.5), x ₀ ∈ [0,1], initialize a chaotic map as a key, and generate a set of iteration results

时，可将

作为p 值。Use the above iterative results in pairs as new control parameters and initial conditions to initialize a set of chaotic maps. Note that due to p∈(0,0.5), when the iteration result

when, you can

as a p-value.

After initialization, multiple chaotic maps can work in parallel and generate iteration results at the same time, effectively improving the speed of iteration result generation.

该序列可用于加解密。When the chaotic map generates enough keys, all generated iteration results are combined according to certain rules. As shown below, all iteration results can be organized in sequential order as

This sequence can be used for encryption and decryption.

For the above process, the method of updating the chaotic map is shown in Figure 5a and Figure 5b:

In Figure 5a, for the chaotic map on the left side of the way, after reaching the upper limit of the iteration, iterate twice, and use the two iteration results as the control parameters and initial conditions to reinitialize itself.

In Figure 5b, for the chaotic map that generates iteration results in parallel, after the upper limit of iteration is reached, the left chaotic map in the figure continues to iterate to generate a new set of iterative results, and the right chaotic map is reinitialized.

So far, those skilled in the art should appreciate that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, without departing from the spirit and scope of the present invention, the disclosed embodiments of the present invention can still be used. Many other variations or modifications consistent with the principles of the invention are directly identified or derived from the content. Accordingly, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims (7)

1. A key stream generator parallelization and anti-dynamic degradation method, is characterized in that, S1. Receive the initial key; S2. Based on the initial key, use the preset key stream generator initialization method on all key stream generators to initialize the key stream generators at the same time or step by step. After initialization, the key stream generators use the preset parallel working method , to generate the keystream in parallel; S3. Combining the key stream generated by the key stream generator using a preset combination method to generate a final key stream for encryption and decryption. S4. After the key stream generator iterates to the specified iteration upper limit, the key stream generator is reinitialized by using a preset key stream generator reinitialization method. 2. A kind of key stream generator parallelization and anti-dynamic degradation method according to claim 1, it is characterized in that: initial key has at least 1 key, and 1 key is used for completing 1 key stream Initialization of the generator, 1 key consists of at least 1 parameter. 3. A kind of key stream generation parallelization and anti-dynamic degeneration method according to claim 1, is characterized in that: key stream generator adopts mapping iteration method to generate iteration result, and concrete process is as follows: The map is denoted as F, the key is denoted as k ₀ , and the key is substituted into the map to complete the initialization of the key stream generator: F(k ₀ )=z ₁ , where z ₁ is called the iteration result; Use z ₁ to replace one or more parameters in k ₀ to get k ₁ , and substitute k ₁ into the map: F(k ₁ )=z ₂ , and iterate according to F(k _i-1 )= _zi to generate a Group iteration results (keystream) z ₁ ,...,z _n . 4. according to claim 1 or 3 described a kind of key stream generator parallelization and anti-dynamic degeneration method, it is characterized in that: remember key stream generator total number is M, then At the same time in the S2, the key stream generator is initialized, including: Initializing M key stream generators based on the initial key, where the number of keys in the initial key is M; The steps in S2 initialize the key stream generator, including: First use the initial key to initialize K key stream generators, the number of keys in the initial key is K, where 1≤K≤M, and then use the iteration results of K key stream generators according to k ₀ The structure constructs MK keys, and completes the initialization of the remaining key stream generators. 5. A kind of key stream generator parallelization and anti-dynamic degradation method according to claim 4, it is characterized in that: described preset parallel working method comprises: In the case of initializing the key stream generators in S2 at the same time: all key stream generators iterate in parallel, and the generated iteration results are combined using a preset combination method to generate the final key stream for encryption and decryption; In the case of step-by-step initialization of key stream generators in S2: K (1≤K≤M) key stream generators are used to generate keys, where M is the total number of key stream generators, and the remaining The M-K key stream generators are initialized, and the M-K key stream generators iterate in parallel, and the generated iteration results are combined using a preset combination method to generate the final key stream for encryption and decryption. 6 . The method for parallelizing and anti-dynamic degradation of a key stream generator according to claim 5 , wherein the preset combination method includes sequential arrangement, alternate arrangement and scrambling arrangement. 7 . 7. A kind of key stream generator parallelization and anti-dynamic degradation method according to claim 1, is characterized in that, in described S4, preset key stream generator reinitialization method comprises: Select the corresponding selected iteration result from the key stream generator's own iteration result to construct a new key, substitute the new key into the map, and re-initialize the map; and / or Select corresponding iteration results from other key stream generator iteration results to construct a new key, substitute the new key into the map, and reinitialize the map.

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