Method of information encryption transmission system based on improved national secret algorithm

Abstract

The invention discloses a method of an information encryption transmission system based on an improved national cryptographic algorithm, and the method comprises the steps: firstly carrying out the white-box optimization of an SM4 algorithm, and based on the improvement, providing a novel hybrid encryption system integrating the optimized SM4 and SM2 algorithms. The optimized SM4 algorithm can effectively resist attacks based on difference calculation and table look-up combination, and has higher security compared with the original SM4 algorithm. The information encryption transmission system focuses on increasing the speed of ciphertext processing and guaranteeing the safety of data transmission, in the encryption process, the application of the SM4 algorithm ensures the rapid and safe encryption of data, the introduction of the SM2 algorithm optimizes the distribution and management of secret keys, and the encryption efficiency is improved. And the superiority is shown when the key distribution problem in a large-scale system is processed. And through a hybrid scheme of the national cryptographic algorithm, the dependence on an imported encryption algorithm is reduced, the security and practicability are ensured, and diversified application requirements in the field of network security are adapted.

Description

Technical Field

[0001] This invention relates to the field of information encryption, and more specifically to a method for an information encryption transmission system based on an improved Chinese national cryptographic algorithm. Imported encryption algorithms may contain hidden "trapdoors" in their design and implementation, leading to security vulnerabilities; therefore, relying on imported encryption algorithms poses certain security risks. my country's independently developed national cryptographic algorithms have gained widespread international recognition and have been incorporated into the global standards system. Among the national cryptographic algorithms involved in this method, the SM2 algorithm is an asymmetric encryption algorithm suitable for scenarios such as digital signatures and key exchange; the SM4 algorithm is a symmetric encryption algorithm suitable for scenarios such as data encryption and decryption. Combining these two algorithms to form a hybrid encryption scheme can fully leverage the advantages of both national cryptographic algorithms, ensuring efficient data encryption, optimizing key distribution and management, and demonstrating its superiority in handling key distribution problems in large-scale systems. Background Technology

[0002] In the current cyber environment, information protection faces severe challenges, with cyberattacks and data breaches constantly threatening national interests and social stability. Currently, mainstream encryption algorithms such as RSA and AES are widely used internationally, but they have certain shortcomings. The security of these algorithms primarily relies on the difficulty of large number factorization and brute-force attacks. However, with the development of quantum computing technology, large number factorization and brute-force attacks will become feasible, thus threatening the security of these algorithms. Secondly, the design and implementation of these algorithms may contain hidden "trapdoors" that lead to security vulnerabilities, and relying on imported encryption algorithms poses certain security risks.

[0003] China's independently developed encryption standards have gained widespread international recognition and have been incorporated into the global standards system. Among these standards, the SM4 algorithm is favored for its high processing speed and adjustable key and block lengths due to its symmetric key system; however, it still faces challenges in key storage, management, and transmission. The SM2 algorithm, as an asymmetric key system, offers a higher level of security and can handle key management issues, but it is somewhat less effective at encrypting large amounts of data.

[0004] In addition to performance considerations, information transmission systems also need to face attacks from the outside. Since differential attacks do not rely on a deep understanding of the internal structure of the encryption algorithm, but rather on monitoring the changes in data during the encryption process to infer the key, the SM4 algorithm cannot effectively defend against such attacks.

[0005] In response to the above analysis, there is an urgent need to design an information encryption transmission system based on Chinese national cryptographic algorithms. Utilizing the complementary characteristics of the SM4 and SM2 algorithms in different application scenarios, a reasonable integration of the two can effectively overcome the shortcomings of a single algorithm. Furthermore, for the SM4 algorithm, white-box cryptography is an excellent optimization scheme; designing a robust white-box scheme resistant to cryptographic attacks can also improve the security of the information encryption transmission system. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for an information encryption transmission system based on an improved national cryptographic algorithm. It integrates a hybrid encryption scheme combining the SM4 symmetric encryption algorithm and the SM2 asymmetric encryption algorithm to leverage the advantages of both in terms of security and efficiency. Simultaneously, a white-box cryptographic scheme is designed for the SM4 algorithm, optimizing its algebraic properties, thereby increasing the complexity and cost of analysis and significantly enhancing its resistance to differential computation analysis.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An information encryption transmission system based on an improved national cryptographic algorithm includes an encryption communication device (Phytium S500C), a decryption communication device (Phytium S500C), and a communication transmission scheme (Qinglong Technology Scheme). A method for using the information encryption transmission system based on the improved national cryptographic algorithm comprises the following steps:

[0009] Step 1: The sender generates an SM4 key using the SM4 key expansion algorithm through an encrypted communication device, and then uses an improved version of the SM4 algorithm to encrypt the original text information.

[0010] Step 2: The encrypted communication device uses the SM2 algorithm to further encrypt the SM4 encryption key obtained in the above steps, generating an SM4 key information block for transmission;

[0011] Step 3: The encrypted communication device uses digital signature technology, combined with the sender's private key, to sign the original text, thereby generating a digital digest of the original text, i.e., the signature information block;

[0012] Step 4: The communication transmission scheme sends the encrypted text information, the SM4 key information block, and the signature information block containing the digital digest to the recipient.

[0013] Step 5: The receiver uses its private key to decrypt the received SM2 encrypted key information block through the decryption communication device, thereby recovering the original SM4 key.

[0014] Step Six: Decryption The communication device will use the recovered SM4 key to decrypt the received ciphertext in order to reconstruct the original plaintext information;

[0015] The decryption communication device uses the sender's public key to verify and decrypt the transmitted signature information block. At the same time, it compares the digest provided by the encryption communication device with the digest calculated by the decryption communication device. If the digest information matches, it ensures that the data has not been tampered with during transmission.

[0016] The improved SM4 algorithm optimization scheme embeds an 8-bit nonlinear substitution in the output of the TD table and combines it with 32 TE tables to perform an XOR operation, so that all nonlinear transformations are integrated into the lookup table. Attackers cannot extract the nonlinear transformations or round key information separately, thus improving security.

[0017] This invention first performs white-box optimization on the SM4 algorithm. Based on these improvements, we propose a novel hybrid encryption system that integrates the optimized SM4 and SM2 algorithms. The optimized SM4 algorithm effectively resists differential calculation summation attacks based on lookup table combinations, offering higher security compared to the original SM4 algorithm. The information encryption transmission system proposed in this invention focuses on improving the speed of ciphertext processing and ensuring the security of data transmission. During the encryption process, the use of the SM4 algorithm ensures fast and secure data encryption, while the introduction of the SM2 algorithm optimizes key distribution and management, demonstrating its superiority in handling key distribution problems in large-scale systems. Furthermore, this hybrid scheme also optimizes the digital signature and authentication processes, making them more efficient and reliable.

[0018] The cryptographic table of the national cryptographic algorithm SM4 is optimized. An 8-bit nonlinear substitution is implemented in the output encoding of the TD lookup table, and XOR operation is performed in combination with 32 TE tables. All nonlinear transformations are integrated into the lookup table. Even if an attacker obtains the memory data, the attacker cannot extract the nonlinear transformation or round key information separately.

[0019] A hybrid scheme integrating the optimized SM4 symmetric encryption algorithm and the SM2 asymmetric encryption algorithm was designed. The use of the optimized SM4 algorithm ensures fast and secure encryption of data, while the introduction of the SM2 algorithm optimizes key distribution and management and adds digital signature functionality, providing additional guarantees for data security and integrity.

[0020] The most crucial step is to perform white-box optimization on the SM4 algorithm, which can effectively prevent differential analysis attacks targeting the SM4 algorithm.

[0021] Since differential attacks do not rely on a deep understanding of the internal structure of the SM4 algorithm, but rather on inferring the key by monitoring the changes in data during the encryption process, encryption using only the internal encoding of the SM4 algorithm is not an effective defense against such attacks.

[0022] Experiments were designed to verify the security of the existing SM4 algorithm: Information leaked during algorithm runtime was collected using specific software, hereinafter referred to as software traces. First, a byte closely related to the key was extracted from the algorithm's intermediate state, and a bit was selected as the target bit for analysis. For each potential target bit, the following measures were taken:

[0023] (1) Based on whether the value of the target bit is 0 or 1, the software trace is divided into two different groups.

[0024] (2) Calculate the average trace of the software trace for each group.

[0025] (3) Difference the two average traces to obtain the difference trace.

[0026] (4) Evaluate all possible key byte hypotheses by observing their performance at the peaks of the differential traces to determine the best key byte hypothesis. In this process, select the hypothesis with the most significant peak as the most likely key byte.

[0027] Differential analysis was performed on the SM4 encryption algorithm, keeping the random matrix and random vector used in the algorithm encoding constant. Mutational differential analysis was conducted on 10 different initial key configurations to explore the accuracy of the analysis under different sample sizes. Detailed research results are shown in Table 1-1.

[0028] Table 1-1 Accuracy of SM4 Difference Calculation

[0029] Sample size 10 20 23 30 100 accuracy 0％ 0％ 50％ 100％ 100％

[0030] As shown in Table 1-1, when the software used for analysis has sufficient traces, the analysis accuracy can reach 100%, which indicates that SM4 cannot resist differential calculation analysis.

[0031] When performing differential computation analysis on the optimized white-box SM4 scheme, the sampling analysis analyzed 100 samples. The results showed that the analysis tool failed to give the correct results regardless of the initial key or encoding selected. Figure 3-1 and Figure 3-2 The differential trace plots corresponding to the optimal target bit are presented when the key byte guess is correct and when the guess is incorrect. These plots show that regardless of the accuracy of the guess, the differential trace plots appear as smooth line segments without obvious distinguishing features, making them unrecognizable. Therefore, this improved scheme can effectively defend against differential computation analysis attacks.

[0032] To verify the performance of the encrypted transmission system designed using this method against existing mainstream encryption algorithms, a comparative experiment was conducted as follows:

[0033] Several documents were carefully selected and adjusted to meet the specific data scale requirements of the experiment; all were in txt file format. Data sets of 500KB, 1MB, 10MB, and 20MB in size were prepared. Two different encryption algorithm combinations were applied to these txt files of different sizes. After each algorithm was repeated 30 times, their average time complexity was compared. Tables 1-3 show that both the hybrid encryption algorithm based on the improved SM4 and SM2 combination exhibited faster key generation speed. Conversely, the encryption algorithm combining RSA and SM4 showed an increase in key generation time with the increase in the amount of data processed.

[0034] Table 1-3 Comparison of key generation time for the three algorithms

[0035] Data size RSA+SM4(ms) SM2+SM4(ms) 500KB 17.0 1 1M 17.2 1 10M 18.3 1 20M 19.9 1

[0036] In-depth analysis of the chart data reveals that the proposed SM2 and SM4 hybrid encryption algorithm does not show a significant correlation between key generation time and data volume; the key generation speed remains relatively fast regardless of the data volume. On the other hand, the encryption algorithm combining RSA and SM4 exhibits a linear increase in key generation time with increasing data volume.

[0037] Tables 1-4 provide a detailed record of the encryption time for the two different algorithms when handling various data sizes. These analyses clearly show that the encryption time for all three examined algorithms is positively correlated with the data size; that is, the larger the data volume, the longer the required encryption time.

[0038] Table 1-4 Comparison of Encryption Time

[0039] Data size RSA+SM4(ms) SM2+SM4(ms) 500KB 6.2 7.9 1M 15.4 9.2 10M 103.0 75.1 20M 205.7 171.0

[0040] Further comparison of encryption times reveals that the hybrid encryption algorithm has a significant advantage in efficiency over other algorithms, especially when the data size is in the range of 1MB to 20MB. The improved SM2 and SM4 hybrid algorithm in this study has a shorter encryption time than other hybrid algorithms, significantly improving encryption efficiency.

[0041] Table 1-5 details the time required for two different hybrid encryption algorithms to perform digital signature operations on data of various sizes. The table shows that the time required for both algorithms to perform digital signatures increases linearly with the amount of data. However, based on experimental data, the improved SM4 and SM2 hybrid encryption algorithm has a more significant advantage in time efficiency for digital signatures compared to the other algorithm.

[0042] Table 1-5 Comparison of signature time required for two algorithms

[0043] Data size RSA+SM4(ms) SM2+SM4(ms) 500KB 3.6 3.0 1M 6.1 4.2 10M 57.6 51.1 20M 107.8 99.2

[0044] Furthermore, Tables 1-6 compare the time required by the two decryption algorithms when processing data of different sizes. It can be observed that the decryption time increases linearly with the amount of data, indicating a direct proportionality between data size and decryption time. When comparing the two hybrid encryption algorithms, the proposed optimized SM4 / SM2 hybrid algorithm exhibits relatively shorter decryption times and better time efficiency as the amount of data processed increases. These findings are significant for understanding the performance of different encryption algorithms when processing large-scale data and provide experimental evidence for selecting appropriate decryption strategies.

[0045] Table 1-6 Comparison of Decryption Time

[0046] Data size RSA+SM4(ms) SM2+SM4(ms) 500KB 6.7 5.9 1M 13.2 7.1 10M 89.3 66.2 20M 174.8 155.9

[0047] A comprehensive examination was conducted on the four key stages of key generation, encryption, decryption, and digital signature and decryption, with a detailed analysis of the time consumption of different algorithms. As shown in Table 1-7, the optimized SM4 / SM2 hybrid encryption algorithm demonstrates outstanding overall performance in these aspects, placing it in a leading position.

[0048] Table 1-7 Performance Comparison of Two Schemes

[0049] Key generation SM2+SM4>RSA+SM4 encryption SM2+SM4>RSA+SM4 Decryption SM2+SM4>RSA+SM4 Digital Signature SM2+SM4>RSA+SM4

[0050] To ensure information security during transmission, this paper employs the SM4 algorithm to encrypt sensitive data. To further enhance key security, an innovative encryption strategy is adopted: encrypting the SM4 key using the SM2 encryption algorithm. This process ensures that only authorized recipients with the correct decryption key can unlock the encrypted data, effectively reducing the risk of sensitive information leakage. Furthermore, to verify the identities of both communicating parties and ensure the integrity of transmitted information, public-key digital signatures and message verification codes are introduced. In this way, the combination of SM2 and SM4 algorithms not only improves data transmission security but also cleverly solves the security challenges encountered by SM4 in key distribution. The application of this hybrid encryption mechanism enhances the flexibility and reliability of key management, significantly improves the defense against man-in-the-middle attacks, and effectively prevents unauthorized data access and eavesdropping even in the event of accidental key loss.

[0051] The system structure of this invention comprises three main modules: an encrypted communication device, a decryption communication device, and a communication transmission scheme. The encrypted communication device is used to encrypt communication content and complete digital signatures, the decryption communication device is used to decrypt and verify digital signatures, and the communication transmission scheme is responsible for the transmission of ciphertext and keys between the encrypted and decryption devices.

[0052] Compared with the prior art, the present invention has the following advantages and effects:

[0053] 1. Hybrid schemes based on national cryptographic algorithms help reduce reliance on imported encryption algorithms.

[0054] 2. The introduction of public key digital signature and message verification code mechanisms not only improves the security of data transmission, but also cleverly solves the security problems encountered by SM4 in the key distribution process.

[0055] 3. The application of this hybrid encryption mechanism enhances the flexibility and reliability of key management, significantly improves the defense against man-in-the-middle attacks, and can effectively prevent unauthorized data access and eavesdropping even in the event of accidental key loss.

[0056] 4. It ensures both security and practicality, adapting to diverse application needs in the field of network security. Attached Figure Description

[0057] Figure 1 A schematic diagram illustrating the data processing flow of a method for an information encryption transmission system based on an improved national cryptographic algorithm;

[0058] Figure 2 This is a schematic diagram of the overall module of an information encryption transmission system based on an improved national cryptographic algorithm.

[0059] Figure 3-1 A schematic diagram of differential traces when the key bytes are correct.

[0060] Figure 3-2 A schematic diagram of the differential trace when there is a key byte error. Detailed Implementation

[0061] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0062] Example 1:

[0063] An information encryption transmission system based on an improved national cryptographic algorithm includes an encryption communication device (any existing device), a decryption communication device (any existing device), and a communication transmission scheme (any existing device); a method for information encryption transmission system based on an improved national cryptographic algorithm includes the following steps:

[0064] I. SM4 Improvement Methods:

[0065] This study proposes a novel white-box implementation scheme for the SM4 algorithm, the specific design of which is as follows:

[0066] In the first round, to protect the lookup table associated with the key, we employ non-linear encoding, as shown in formula (1-1) below:

[0067]

[0068] Here, I 0,j =I 0,j,1 ||I 0,j,2 ||I 0,j,3 Each part is an 8-bit non-linear replacement, adding non-linear encoding to the TD table. The output c of the TC table... 1,i With the output d of the TD table 1,i Since XOR operations cannot be performed directly, an additional XOR table is required. We define:

[0069]

[0070]

[0071] c 1,i C1 can be obtained directly by performing an XOR operation. However, calculating d1 requires 12 XOR tables that map 16-bit inputs to 8-bit outputs. For a 16-bit input x = x0||x1, where x0 and x1 are both 8-bit values, the XOR table definition for d1 is as follows:

[0072]

[0073] Here J,I -1 J -1 Both represent 8-bit nonlinear transformations.

[0074] To obtain X′4, we need to calculate Use the following XOR table:

[0075]

[0076] Among them, H,J -1 It is also an 8-bit non-linear replacement.

[0077] For the second to fifth rounds of design, the lookup table is constructed according to the following formula.

[0078]

[0079] In the final stage of the design, we introduced an 8-bit nonlinear transformation into the output of the TD table, along with a corresponding TE table to perform the XOR operation. This scheme embeds an 8-bit nonlinear substitution into the output of the TD table and combines it with 32 TE tables to perform the XOR operation. Even if an attacker gains access to the memory data, because all nonlinear transformations are integrated into the lookup table, the attacker cannot extract the nonlinear transformations or round key information separately.

[0080] Example 2:

[0081] like Figure 1 , 2 As shown, an information encryption transmission system based on an improved national cryptographic algorithm includes an encryption communication device (any existing device), a decryption communication device (any existing device), and a communication transmission scheme (any existing device); a method for an information encryption transmission system based on an improved national cryptographic algorithm includes the following steps:

[0082] Step 1: The sender generates an SM4 key using the SM4 key expansion algorithm through an encrypted communication device, and then uses an improved version of the SM4 algorithm to encrypt the original text information.

[0083] Step 2: The encrypted communication device uses the SM2 algorithm to further encrypt the SM4 encryption key obtained in the above steps, generating an SM4 key information block for transmission;

[0084] Step 3: The encrypted communication device uses digital signature technology, combined with the sender's private key, to sign the original text, thereby generating a digital digest of the original text, i.e., the signature information block;

[0085] Step 4: The communication transmission scheme sends the encrypted text information, the SM4 key information block, and the signature information block containing the digital digest to the recipient.

[0086] Step 5: The receiver uses its private key to decrypt the received SM2 encrypted key information block through the decryption communication device, thereby recovering the original SM4 key.

[0087] Step Six: Decryption The communication device will use the recovered SM4 key to decrypt the received ciphertext in order to reconstruct the original plaintext information;

[0088] The decryption communication device uses the sender's public key to verify and decrypt the transmitted signature information block. At the same time, it compares the digest provided by the encryption communication device with the digest calculated by the decryption communication device. If the digest information matches, it ensures that the data has not been tampered with during transmission.

[0089] The SM4 encryption method for encrypted communication devices is as follows:

[0090] The encrypted communication device uses the SM4 algorithm to encrypt 128-bit blocks. The data length during the encryption process is 4 bytes. The encryption process includes 32 rounds of loop operations and a final reverse transformation R.

[0091] Let the plaintext input be Ciphertext output is Round key is The 32 iterations (1-13) and the reverse transformation (1-14) are as follows:

[0092]

[0093] (Y0,Y1,Y2,Y3)=R(X 32 ,X 33 ,X 34 ,X 35 )=(X 35 ,X 34 ,X 33 ,X 32 (1-14)

[0094] The SM2 encryption and decryption methods for communication devices are as follows:

[0095] Before encrypting plaintext data M, it needs to be converted into elliptic curve E through mapping. p A point on (a,b) is given, while ensuring that M∈GF(p). Before encrypting plaintext data M, it needs to be transformed into an elliptic curve E through mapping. p A point on (a,b), while ensuring that M∈GF(p).

[0096] (1) Encryption steps:

[0097] Randomly select an integer r, ensuring that it is less than n;

[0098] The plaintext M is transformed into an elliptic curve E using the mapping function ENC. p Point P in (a,b) m (x,y), denoted as P m =ENC(M)

[0099] Calculations yield C1 and C2: C1 = rG, C2 = P m+rK p ;

[0100] Send a pair of ciphertext (C1, C2) to the decryption device.

[0101] (2) Decryption steps:

[0102] The decryption device receives the ciphertext pair (C1, C2);

[0103] Calculate C2-K s C1 = P m +rK p -K s rG=P m +rK s GK s rG=P m ;

[0104] Using the inverse process of the mapping function ENC to P m Decode and restore the plaintext data M.

[0105] The digital signature method is as follows:

[0106] In the digital signature process implemented using the SM2 algorithm, the initial step involves applying the SM3 algorithm to the original information to generate a corresponding hash digest H. Subsequently, this digest is combined with the signer's private key to perform a signature operation, forming the final signature output. The verification phase combines the public key, signature data, and hash digest H to perform verification steps to authenticate the signature's legitimacy.

[0107] (1) The process of generating a digital signature:

[0108] When an encrypted communication device signs a message M and sends it to a decryption communication device, it should perform the following sequence of operations:

[0109] Randomly select an integer k∈[1,n-1];

[0110] Calculate the points on the elliptic curve. Given kG = (x1, y1) and x1 ∈ Z, calculate r = x1 mod n. If r = 0, repeat the step.

[0111] Solve for t = k -1 mod n, get the value of t;

[0112] The SM3 algorithm is used to obtain the hash value e = H(M) of the plaintext M;

[0113] Solve for s = k -1 (e+K s If r)modn, and s=0, then return to step one;

[0114] Send message M along with its signature (r,s) to the decryption communication device.

[0115] (2) Verification of digital signature process:

[0116] After receiving message M and signature (r,s), the decryption communication device should perform the following verification process:

[0117] Check the validity of r and s, verify whether r and s satisfy r,s∈[1.n-1], if not within this range, the verification fails;

[0118] Calculate e = H(M) and w = s -1 modn, u1=ew modn, u2=rwmodn and U=u1G+u2K p = (x2, y2);

[0119] If U = 0, the verification fails; if U ≠ 0, further calculate v = x²modn.

[0120] If v = r, the signature verification is valid; if v ≠ r, the verification fails.

[0121] The system structure is as follows:

[0122] Figure 2 An example is a schematic diagram of the system architecture, such as... Figure 2 As shown, the system may include: an encrypted communication device 201, a communication transmission scheme 202, and a decryption communication device 203, wherein the encrypted communication device 201 and the decryption communication device 203 communicate with each other through the communication transmission scheme 202.

[0123] In this process, the encrypted communication device 201 generates an SM4 key using the SM4 key extension algorithm and encrypts the original text information using an improved version of the SM4 algorithm. The encrypted communication device further encrypts the SM4 encryption key obtained in the previous steps using the SM2 algorithm, generating an SM4 key information block for transmission. The encrypted communication device then uses digital signature technology, combined with the sender's private key, to sign the original text, thereby generating a digital digest of the original text, i.e., a signature information block. The communication transmission scheme 202 combines the encrypted text information, the SM4 key information block, and the signature information block containing the digital digest, and sends them to the decryption communication device 203. The decryption communication device uses its private key to decrypt the received SM2-encrypted key information block, thereby recovering the original SM4 key. The decryption communication device then uses the recovered SM4 key to decrypt the received ciphertext to reconstruct the original plaintext information. Finally, the decryption communication device uses the sender's public key to verify and decrypt the transmitted signature information block, and compares the digest provided by the encrypted communication device with the digest calculated by the decryption communication device. If the digests match, it ensures that the data has not been tampered with during transmission.

[0124] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0125] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An information encryption transmission system based on an improved national cryptographic algorithm, characterized in that: Includes encrypted communication equipment, decryption communication equipment, and communication transmission scheme; a method for an information encryption transmission system based on an improved national cryptographic algorithm, the steps of which are: Step 1: The sender generates an SM4 key using the SM4 key expansion algorithm through an encrypted communication device, and then uses an improved version of the SM4 algorithm to encrypt the original text information. Step 2: The encrypted communication device uses the SM2 algorithm to further encrypt the SM4 encryption key obtained in the above steps, generating an SM4 key information block for transmission; Step 3: The encrypted communication device uses digital signature technology, combined with the sender's private key, to sign the original text, thereby generating a digital digest of the original text, i.e., the signature information block; Step 4: The communication transmission scheme sends the encrypted text information, the SM4 key information block, and the signature information block containing the digital digest to the recipient. Step 5: The receiver uses its private key to decrypt the received SM2 encrypted key information block through the decryption communication device, thereby recovering the original SM4 key. Step Six: Decryption The communication device will use the recovered SM4 key to decrypt the received ciphertext in order to reconstruct the original plaintext information; The decryption communication device uses the sender's public key to verify and decrypt the transmitted signature information block. At the same time, it compares the digest provided by the encryption communication device with the digest calculated by the decryption communication device. If the digest information is consistent, it ensures that the data has not been tampered with during transmission.

2. The information encryption transmission system based on the improved national cryptographic algorithm according to claim 1, characterized in that: The improved SM4 algorithm optimization scheme embeds an 8-bit nonlinear substitution in the output of the TD table and combines it with 32 TE tables to perform an XOR operation, so that all nonlinear transformations are integrated into the lookup table. Attackers cannot extract the nonlinear transformations or round key information separately, thus improving security.

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