Information hiding intelligence transmission method based on lattice password signature domain

Abstract

The invention discloses an information hiding information transmission method based on a lattice cipher signature domain, which supports both communication parties to extract secret information at the same time under the condition of correct verification of a signature, thereby completing information hiding and communication on the lattice cipher protocol signature domain on the basis of a lattice cipher protocol. All operations of the two communication parties are recorded, and it is guaranteed that the operation track reserved traces of the two parties can be traced back. Meanwhile, the client side and the server side are constructed, the server side is responsible for managing information and operation of the client side, and the client side can serve as an information sender and an information receiver for communication. Based on the fault tolerance of the lattice password, the method achieves the extraction of secret information and the lossless recovery of carriers on the premise of not needing any external information, improves a classical differential extension steganography scheme, and guarantees the information embedding bit rate even if the number of carriers is small.

Description

Technical Field

[0001] The present invention relates to the technical field of information hiding, and in particular to an information hiding intelligence transmission method based on a lattice cryptographic signature domain. Background Art

[0002] When discussing the innovation direction of current information hiding and intelligence transmission technology, traditional methods mostly focus on two core areas of image processing: spatial domain and frequency domain. Classical techniques in the spatial domain, such as the least significant bit (LSB) embedding method, are simple and easy to use, but they are easily detected by statistical methods such as chi-square analysis because they directly modify the lowest bit of the image pixel value, exposing the existence of steganographic operations. On the other hand, frequency domain techniques, such as information hiding in the discrete cosine transform (DCT) and discrete Fourier transform (DFT) domains, can achieve information embedding while maintaining low distortion, but these methods are highly dependent on carriers with complex variable correlations such as images, which limits their versatility and flexibility. What is particularly critical is that these technologies have failed to fundamentally solve the problem of inevitable permanent distortion of the original carrier after embedding information. This defect significantly increases the risk of being detected by a third party during information transmission.

[0003] In addition, with the rapid development of quantum computing technology, the traditional intelligence transmission system based on modern cryptography is facing unprecedented security challenges. The rise of quantum cryptography indicates the vulnerability of traditional encryption methods in quantum computing environments, forcing us to seek more secure and reliable intelligence protection strategies. Summary of the invention

[0004] The purpose of the present invention is to solve the above defects in the prior art and provide an information hiding intelligence transmission method based on lattice cryptographic signature domain. The method integrates information hiding technology into the advanced lattice cryptography framework, and utilizes the unique mathematical complexity and security of lattice cryptography to achieve the hidden embedding and efficient transmission of secret information.

[0005] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0006] An information hiding intelligence transmission method based on a lattice cryptographic signature domain, the information hiding intelligence transmission method comprising the following steps:

[0007] S1. The intelligence sender uses the system establishment algorithm Setup (Info) to establish the system. Info is the input, which is the identity information of the intelligence sender. After the identity information is successfully verified, the system is established and operated. The intelligence sender is not only the sender of intelligence, but also the generator of public and private keys and the sender of public keys.

[0008] S2. The intelligence receiver uses the system establishment algorithm Setup (Info) to establish the system. Info is the input, which is the identity information of the intelligence receiver. After the identity information is successfully verified, the system is established and operated. The intelligence receiver is both the receiver of the intelligence and the receiver of the public key.

[0009] S3. The intelligence sender uses the public key function SendPKE to generate a public key Pk and a private key Sk, keeps the private key Sk private, and sends the public key Pk to the intelligence receiver;

[0010] S4. The intelligence sender selects the required transmission method for intelligence transmission, where the transmission methods include two types: a signature method without secret information and a signature method with secret information. If the intelligence sender selects a signature method without secret information, the intelligence sender uses the private key Sk generated by itself as the signature key and calls the function NoSecretSign(Message, Sk) to sign the plaintext Message to generate a signature S. The system then sends the plaintext and the generated signature to the intelligence receiver, where the input of the function NoSecretSign(Message, Sk) is the plaintext Message and the private key Sk, and the output is the signature S, where the signature S belongs to the signature domain and is in the form of a matrix. Each element in the matrix stores the corresponding data element, and each data element is stored in the matrix in decimal. If the intelligence sender selects a signature method with secret information, the function Embed is called. Sign(Message, Sk, Secret, LenSecret) generates a signature S, and uses the differential extended steganography function DE_HS_n_H(Carrier, Secret) on the signature to hide information and generate a signature S′, and sends the plaintext and the new signature S′ to the intelligence receiver, where the input of the function EmbedSign(Message, Sk, Secret, LenSecret) is the plaintext Message, the private key Sk, the secret information Secret and the length of the secret information LenSecret, and the output is the signature S, the input of the differential extended steganography function DE_HS_n_H(Carrier, Secret) is the carrier Carrier and the secret information Secret, the carrier Carrier corresponds to the signature S and the secret information Secret corresponds to the information to be hidden, and the output is the new signature S′;

[0011] S5. After receiving the plaintext and signature, the intelligence receiver selects the required processing method to verify the information. There are two verification methods: direct verification and verification after extracting secret information. If direct verification is selected, the direct verification function Verrify(S, Message, Pk) is called for direct verification to obtain the verification result. The input of the function Verrffy(S, Message, Pk) is the signature S, the plaintext Message, and the public key Pk, and the output is the verification result. If verification is selected after extracting secret information, the differential extension extraction function DE_HS_n_E(S) is first called to extract the secret information. The input of the function DE_HS_n_E(S) is the signature S, and the output is the secret information. Then the function Verrify(S, Message, Pk) is called to obtain the verification result.

[0012] Furthermore, in the system establishment algorithm Setup (Info), the intelligence receiver or the intelligence sender inputs personal identity information Info by connecting to the back-end database, verifies the personal identity information Info with the back-end database information, and determines whether the system establishment is successful or not based on the verification result. If the verification is successful, the system of the intelligence receiver or the intelligence sender is established, the intelligence receiver database and the intelligence sender database are generated, and the system function is called, wherein the intelligence receiver database includes a public key data table, a plaintext and signature table, and the intelligence sender database includes a private key data table. If the verification fails, the system cannot be established, and the information hiding intelligence transmission method cannot be started.

[0013] Furthermore, during the implementation of the public key sending function SendPKE, the system generates a random public key-private key pair, both of which are in matrix form, and the element types in the matrix are all decimal numbers. The generated public key is transmitted to the public key data table of the intelligence receiver by connecting to the back-end database, and the private key is stored in the private key data table of the intelligence sender, wherein the public key data table stores all public keys received by the intelligence receiver, and the private key data table stores all private keys saved by the intelligence sender.

[0014] Furthermore, in the process of implementing NoSecretSign(Message, Sk) sent by the intelligence sender in a signature mode without secret information, the intelligence sender connects to the backend database, selects the private key used for the signature from the private key data table, inputs the message Message to be signed, and then the system signs the message, generates a signature S, encapsulates the message Message, signature S and other descriptive information and sends them to the plaintext and signature table of the intelligence receiver's database, where the other descriptive information includes the length LenSecret of the secret information, and the length of the secret information of the signature information without secret information is 0.

[0015] Furthermore, during the direct verification function Verify(S, Message, Pk), by connecting to the back-end database, the intelligence receiver selects the message Message and signature S to be verified from the plaintext and signature information table, and selects the public key corresponding to the signature from the public key data table. The system uses the signature S to verify the message Message, obtains the verification result and outputs it.

[0016] Furthermore, in the implementation of the differential extended steganographic function DE_HS_n_H (Carrier, Secret), the input carrier Carrier is the signature S, the Secret is the information to be hidden, and the matrices S1 and S2 of the signature S = {S1, S2} are concatenated head to tail to convert into an N-dimensional square matrix. First, each element is preprocessed, that is, a constant Num is added, Num = 128 or 256, and the adjacent elements of each row after preprocessing are grouped in pairs, and each row has groups, total groups, N is the dimension of the square matrix formed by splicing matrices S1 and S2 together end to end, calculate the difference h and mean i of each group, form matrix H and mean matrix I, and draw a difference distribution histogram. Then, the hidden information Secret is converted into binary information in the format of ASCII code, and the length of the binary information LenSecret is counted. According to the raster scanning order, the group with the smallest absolute value of the difference and the expandable M-bit all-1 secret information is preferentially selected from the difference histogram, where M is a constant with a limited value range, M=1, 2, 4 or 8, and the maximum absolute value Delta of the selected difference is determined, and the histogram is shifted accordingly; the two LSB valid information of the four corner elements of the shifted matrix is ​​retained, and the LSB is the least significant bit, which is retained at the end of the hidden information Secret in order to generate Secret′; Delta is converted into an 8-bit binary number and embedded in the lowest two LSBs of the four corner elements in order, and then Secret′ is split into groups of M bits, where M is a constant with a limited value range, M=1, 2, 4 or 8, and a secret information group is embedded in each selected difference group in the raster scanning order. The signature generated after the embedding is processed again, that is, Num is added to the value of each element to generate a signature S′ with secret information. The system sends the newly generated signature field and plain text to the plain text and signature table in the intelligence recipient's database.

[0017] Furthermore, when the intelligence sender sends the function EmbedSign(Message, Sk, Secret, LenSecret) in the signature mode containing secret information, the backend database is connected, the intelligence sender selects the private key used for the signature from the private key data table, the intelligence sender inputs the message Message to be signed, the system signs the message Message, generates a signature S, the intelligence sender inputs the secret information Secret to be transmitted and the length of the secret information LenSecret, uses the function DE_HS_n_H(Carrier, Secret) to embed the information on the obtained signature S, and obtains a new signature S′, where the signature S is used as the carrier Carrier. The system encapsulates the message Message, the new signature S′ and other descriptive information and sends them to the plaintext and signature table in the intelligence receiver's database, where other descriptive information includes the length of the secret information LenSecret, and the length of the secret information embedded in the secret information is not 0.

[0018] Furthermore, in the process of implementing the differential extension extraction function DE_HS_n_E(S), the intelligence receiver selects the signature S′ embedded with secret information from the plaintext and signature table, and the system preprocesses the elements in the signature S′. The signature S′ is in the form of a square matrix. Each element in the square matrix is ​​subtracted from Num. The two LSBs of the four corner elements in the square matrix of the signature S′ are extracted in order, and concatenated to form Delta. The difference matrix H′ and the mean matrix I′ are calculated, and the difference range of the embedded secret information is determined according to Delta. The grouping of the embedded secret information is determined according to the raster scanning order, and the number of extended bits is determined according to the number of extended bits. M, extract and concatenate the secret information according to the differential expansion recovery formula to form Secret′. After the extraction, perform a histogram reverse shift operation on the groups and restore the histogram; restore the recovered groups to the signature matrix after the histogram reverse shift to generate S″. The system intercepts the last eight binary bits of Secret′, and the rest is the secret information Secret. The last eight LSB information is restored to S″ in order to generate the original signature S. Finally, the system groups the secret information Secret by 8 bits, converts it into a decimal ASCII code, and returns the embedded secret information.

[0019] Compared with the prior art, the present invention has the following advantages and effects:

[0020] (1) The present invention can not only correctly verify the authenticity of the signature, but also correctly extract the ciphertext information.

[0021] (2) In the invention, the maximum embedding bit rate of the traditional differential expansion scheme is theoretically 0.5, while the invention can exceed this maximum embedding bit rate when the embedding bit number is selected to be 2 and 4. Therefore, under the premise of selecting a suitable embedding bit number and the element distribution range being smaller than the value range, the information hiding scheme can embed a large amount of data on a smaller carrier.

[0022] (3) The present invention implements an intelligence transmission method based on the signature domain of the lattice cryptographic protocol, where the secret information carrier is the signature domain of the lattice cryptographic protocol. This ensures that even if the signature domain is irreversibly distorted, the signature can be successfully verified and the secret information can be extracted, and the operation of embedding the secret message is less likely to be detected by the middleman. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is a logical structure diagram of an intelligence transmission system based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0025] Figure 2 It is a workflow diagram of a client subsystem based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0026] Figure 3 It is an example of a histogram after preprocessing (n=128) in a ciphertext domain intelligence transmission method based on a lattice cipher disclosed in an embodiment of the present invention;

[0027] Figure 4 It is an example of a histogram after information is embedded in a ciphertext domain intelligence transmission method based on a lattice code disclosed in an embodiment of the present invention;

[0028] Figure 5 It is a secret information embedding flow chart based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0029] Figure 6 It is a flow chart of secret information extraction based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0030] Figure 7 It is a flowchart of a client subsystem public key sending program based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0031] Figure 8It is a flowchart of a client subsystem information signature sending program without secret information based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0032] Fig. 9 It is a flow chart of an information signature sending program in which a client subsystem embeds secret information based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0033] Fig.10 It is a flow chart of a client subsystem verification program based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0034] Fig.11 It is a flowchart of a client subsystem extraction program based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention;

[0035] Fig.12 It is a flow chart of an intelligence transmission method based on lattice cryptographic signature domain information hiding disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] With the continuous development of cryptographic technology, more and more companies or individuals need an absolutely secure intranet-specific intelligence transmission system. This intelligence transmission system does not access the network, but it will cause certain distortion to the carrier, making the hidden information easier to be discovered. Therefore, a reversible information hiding method was proposed. However, in real life, the cost of this reversible information hiding method is very high, and with the development of quantum cryptography, it poses a threat to the traditional cryptographic protocol of information transmission. Therefore, how to ensure that the operation of embedding secret information is not easy to detect and make the transmission system more secure and reliable is directly related to the practicality of the intelligence transmission system in various fields.

[0039] In view of the above problems, this embodiment studies the signature domain generated by the lattice cipher hash-and-sign algorithm, proposes an information hiding function DE_HS_n for the signature domain, and designs an intelligence transmission method based on lattice cipher signature domain information hiding. The algorithm transfers the principle of image information hiding to signature domain information hiding. By converting the signature domain into two dimensions, extracting the LSB information at the corresponding position and splicing it into an information extraction key, the secret information can be directly extracted without providing an additional key; and the original image information is stored in the secret information. Through the extraction of the secret information, the lossless recovery of the signature can be achieved, so that the embedding of the secret information will not affect the signature domain itself, which not only realizes the error-free transmission of the original signature, but also embeds more secret messages in the signature domain.

[0040] Combine the following Figure 1-11 The specific process of an intelligence transmission method based on lattice cryptographic signature domain information hiding disclosed in this embodiment is described in detail.

[0041] When establishing communication between the two parties, the lattice cryptographic hash-and-sign algorithm based on the error-tolerant learning problem (LWE) and the short integer solution problem (SIS) is chosen to construct the signature domain, where the parameters of the key generation algorithm are N=512, q=1024.

[0042] An information hiding intelligence transmission method based on a lattice cryptographic signature domain comprises the following steps:

[0043] S1. The intelligence sender uses the system establishment algorithm Setup (Info) to establish the system. Info is the input, which is the identity information of the intelligence sender. After the identity information is successfully verified, the system is established and operated. The intelligence sender is not only the sender of intelligence, but also the generator of public and private keys and the sender of public keys.

[0044] S2. The intelligence receiver uses the system establishment algorithm Setup (Inf0) to establish the system. Info is the input, which is the identity information of the intelligence receiver. After the identity information is successfully verified, the system is established and operated. The intelligence receiver is both the receiver of the intelligence and the receiver of the public key.

[0045] The following will be combined Figure 1 Describe the implementation process of establishing the system algorithm Setup(Inf0):

[0046] T1, connect to the backend database;

[0047] T2, the intelligence receiver or intelligence sender inputs personal identity information Info;

[0048] T3, verify the personal identity information Info with the back-end database information;

[0049] T4. If the verification is successful, the intelligence receiver or intelligence sender system is established, and the intelligence receiver database and intelligence sender database are generated, and the system functions can be used. Among them, the intelligence receiver database includes a public key data table, a plaintext and signature table, and the intelligence sender database includes a private key data table. If the verification fails, the system cannot be established and the information hiding intelligence transmission method cannot be started.

[0050] Figure 1 It indicates that the entire system to be established will include three objects: the server, the intelligence receiver, and the intelligence sender. Each object has a corresponding back-end database. The server authenticates and manages users based on the back-end database, and the intelligence receiver and the intelligence sender complete the transmission of intelligence information based on the back-end database.

[0051] S3. The intelligence sender uses the public key function SendPKE to generate a public key Pk and a private key Sk, keeps the private key Sk private, and sends the public key Pk to the intelligence receiver;

[0052] The following will be combined Figure 7 The following flow describes the implementation process of the public key sending function SendPKE:

[0053] D1. Connect to the backend database;

[0054] D2. The system generates a random public key-private key pair; both the public key and the private key are in the form of a matrix, and the element type in the matrix is ​​a decimal number;

[0055] D3. The system transmits the generated public key to the public key data table of the intelligence receiver, and stores the private key in the private key data table of the intelligence sender. The public key data table stores all public keys received by the intelligence receiver, and the private key data table stores all private keys saved by the intelligence sender.

[0056] S4. The intelligence sender selects the required transmission method for intelligence transmission, where the transmission methods include two types: a signature method without secret information and a signature method with secret information. If the intelligence sender selects a signature method without secret information, the intelligence sender uses the private key Sk generated by itself as the signature key and calls the function NoSecretSign(Message, Sk) to sign the plaintext Message to generate a signature S. The system then sends the plaintext and the generated signature to the intelligence receiver, where the input of the function NoSecretSign(Message, Sk) is the plaintext Message and the private key Sk, and the output is the signature S, where the signature S belongs to the signature domain and is in the form of a matrix. Each element in the matrix stores the corresponding data element, and each data element is stored in the matrix in decimal. If the intelligence sender selects a signature method with secret information, the function Embed is called. Sign(Message, Sk, Secret, LenSecret) generates a signature S, and uses the differential extended steganography function DE_HS_n_H(Carrier, Secret) on the signature to hide information and generate a signature S′, and sends the plaintext and the new signature S′ to the intelligence receiver, where the input of the function EmbedSign(Message, Sk, Secret, LenSecret) is the plaintext Message, the private key Sk, the secret information Secret and the length of the secret information LenSecret, and the output is the signature S, the input of the differential extended steganography function DE_HS_n_H(Carrier, Secret) is the carrier Carrier and the secret information Secret, the carrier Carrier corresponds to the signature S and the secret information Secret corresponds to the information to be hidden, and the output is the new signature S′;

[0057] The following will be combined Figure 8 Describe the implementation process of the message sender sending NoSecretSign(Message, Sk) without signing secret information:

[0058] E1, connect to the backend database;

[0059] E2. The intelligence sender selects the private key used for signing from the private key data table;

[0060] E3. Enter the message to be signed;

[0061] E4. The system signs the information and generates a signature S;

[0062] E5. Encapsulate the message Message, signature S and other descriptive information and send them to the plaintext and signature table in the intelligence receiver's database, where the other descriptive information includes the length LenSecret of the secret information. The length of the secret information of the signature information without secret information is 0.

[0063] The following will be combined Fig. 9 Describe the implementation process of the function EmbedSign(Message, Sk, Secret, LenSecret) sent by the intelligence sender in the signature mode containing secret information:

[0064] G1, connect to the backend database;

[0065] G2. The intelligence sender selects the private key used for signing from the private key data table;

[0066] G3. The sender of the information enters the message to be signed;

[0067] G4. Sign the message Message through the system and generate a signature S;

[0068] G5. The intelligence sender inputs the secret information Secret and the length of the secret information LenSecret to be transmitted, and uses DE_HS_n_H (Carrier, Secret) to embed the information in the obtained signature S to obtain a new signature S′, where the signature S is used as the carrier Carrier;

[0069] G6. The system encapsulates the message Message, the new signature S′ and other descriptive information and sends them to the plaintext and signature table in the intelligence receiver's database. The other descriptive information includes the secret information length LenSecret, and the length of the secret information embedded in the secret information is not 0.

[0070] The following will be combined Figure 3 , Figure 5 To describe the differential extended steganography function DE_HS_n_H (Carrier, Secret) process:

[0071] H1. Connect the signature matrices S1 and S2 of S = {S1, S2} together to form an N-dimensional square matrix. First, preprocess each element, that is, add a constant Num, Num = 128 or 256, and group the adjacent elements of each row after preprocessing. Each row has groups, total groups, N is the dimension of the square matrix formed by splicing the matrices S1 and S2 together end to end, calculate the difference h and mean i of each group, form the difference matrix H and mean matrix I, and draw a difference distribution histogram;

[0072] H2. Convert the hidden information Secret into binary information in the format of ASCII code, count the length of the binary information LenSecret, and select the group of secret information with smaller absolute difference value and expandable M bits of all 1 from the difference histogram in the order of raster scanning, where M is a constant with a limited value range, M=1, 2, 4 or 8, determine the maximum absolute value Delta of the selected difference, and shift the histogram accordingly; retain the two LSB valid information of the four corner elements of the shifted matrix, where LSB is the least significant bit, and retain it at the end of the hidden information Secret in order to generate Secret′; convert Delta into an 8-bit binary number, and embed it into the lowest two LSBs of the four corner elements in order, and then split Secret′ into groups of M bits, where M is a constant with a limited value range, M=1, 2, 4 or 8, and embed a secret information group into each selected difference group in the order of raster scanning;

[0073] H3. After embedding, the generated signature is processed again, that is, Num is added to the value of each element to generate a signature S′ with secret information;

[0074] H4. The system sends the newly generated signature field and plain text to the plain text and signature table in the intelligence recipient's database.

[0075] Figure 5 Embed processes for secret information.

[0076] S5. After receiving the plaintext and signature, the intelligence receiver selects the required processing method to verify the information. There are two verification methods: direct verification and verification after extracting secret information. If direct verification is selected, the direct verification function Verify(S, Message, Pk) is called for direct verification to obtain the verification result. The input of the function Verify(S, Message, Pk) is the signature S, the plaintext Message, and the public key Pk, and the output is the verification result. If verification is selected after extracting secret information, the differential extension extraction function DE_HS_n_E(S) is first called to extract the secret information. The input of the function DE_HS_n_E(S) is the signature S, and the output is the secret information. Then the function Verify(S, Message, Pk) is called to obtain the verification result.

[0077] The following will be combined Fig.10 Describe the direct verification function Verify(S, Message, Pk) process:

[0078] F1, connect to the backend database;

[0079] F2. The intelligence receiver selects the message Message and signature S to be verified from the plaintext and signature information table, and selects the public key corresponding to the signature from the public key data table;

[0080] F3. The system uses the signature S to verify the information Message, obtains the verification result and outputs it.

[0081] The following will be combined Figure 6 and Fig.11 To describe the differential expansion extraction function DE_HS_n_E(S) process:

[0082] N1. The intelligence receiver selects a signature S′ embedded with secret information from the plaintext and signature table;

[0083] N2. The system preprocesses the elements in the matrix S′, that is, subtracts Num from each element. The two LSBs of the four corner elements of the matrix S′ are extracted in order, concatenated into Delta, and the difference matrix H′ and the mean matrix I′ are calculated;

[0084] N3. According to Delta, determine the difference range of the embedded secret information, determine the grouping of the embedded secret information according to the raster scanning order, extract and splice the secret information according to the differential expansion recovery formula according to the extension bit number M, and form Secret′. After the extraction, perform a histogram reverse shift operation on the grouping and restore the histogram; restore the restored grouping to the signature matrix after the histogram reverse shift to generate S″;

[0085] N4. The system intercepts the last eight bits of binary information of Secret′, generates the original secret information Secret, and restores them to S″ in order to generate the original signature S;

[0086] N5. The system groups the secret information Secret by 8 bits, converts it into decimal ASCII code, and returns the embedded secret information.

[0087] Figure 6 Extraction process for secret information.

[0088] Fig.11 The process of extracting and verifying the signature of embedded secret information.

[0089] Example 2

[0090] In Example 2, except for step H2, the same steps as those in Example 1 are adopted. In step H2 in Example 2, groups of all-1 secret information are respectively selected for extension 1, 2, 4, and 8.

[0091] Table 1. Average capacity of different number of bits embedded after the shift strategy is improved

[0092] Embedded Bits Embeddable location Theoretical capacity Actual capacity Embedding bit rate 1 512.0 512 512 0.5000 2 511.99 1024 1022.92 0.9990 4 376.19 1626.92 1201.64 1.1734 8 28.17 186.96 111.52 0.1089

[0093] In order to obtain the maximum embedding capacity and embedding bit rate, it is concluded from the comparison of the experimental results of the embodiments that the optimal embedding bit number in the present invention should be 4 bits as described in the present invention. As can be seen from Table 1, after the histogram shift strategy is improved, the theoretical capacity and actual capacity of the present invention are greatly improved, and the actual embedding bit rate reaches more than 1, far exceeding the maximum embedding bit rate of 0.5 of the traditional differential expansion scheme, greatly improving the information embedding capacity. Figure 4 This is the histogram of the embedded information after the shift strategy is improved. It can be seen that the histogram has become more compact, avoiding difference and element overflow.

[0094] In the company's intranet environment, the implementation of the intelligence transmission mechanism based on the lattice cryptographic signature domain information hiding is as follows: Figure 1 As shown in the figure, the diagram contains three entities, and the operations performed by each entity are as follows.

[0095] (1) Intelligence sender. The sender of intelligence information uses the intelligence client subsystem to sign and hide the intelligence information and send it to the connected client subsystem. Since the sending client needs to store the private key used by the signature algorithm, which comes from itself, it is necessary to establish a database for the client and manage it.

[0096] (2) Intelligence receiver. This is the recipient of intelligence information. It uses the intelligence client subsystem to extract secret information and verify it. Since it is necessary to store the received information and the public key used by the verification algorithm, which comes from the intelligence sender, it is necessary to establish a database for this client and manage it.

[0097] (3) Server: Manage client users and record all information used by the system to control access to the system and ensure system security.

[0098] In summary, in order to resist quantum cryptographic attacks and overcome the drawbacks of traditional information hiding, the above embodiments construct a method for intelligence transmission based on lattice cryptographic signature domain. The present invention supports the use of lattice cryptographic protocol in the intelligence transmission system to realize communication between the two parties. The information communicated by the two parties must be signed and then transmitted to ensure information security. S is the signature generated by the lattice cryptographic hash-and-sign signature algorithm, which overcomes the threat of quantum cryptography. At the same time, the present invention selects the signature domain S as the information hiding carrier and uses the N-bit differential extension steganography scheme with histogram shift for information hiding. The present invention does not require additional keys and can directly extract secret information. In addition, the present invention can realize lossless recovery of the signature, so that the embedding of secret information will not affect the signature domain itself, which not only realizes the error-free transmission of the original signature, but also embeds more secret messages in the signature domain.

[0099] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for information hiding and intelligence transmission based on lattice cryptographic signature domain, characterized in that: The information hiding intelligence transmission method comprises the following steps: S1. The intelligence sender uses the system establishment algorithm Setup (Info) to establish the system. Info is the input, which is the identity information of the intelligence sender. After the identity information is successfully verified, the system is established and operated. The intelligence sender is not only the sender of intelligence, but also the generator of public and private keys and the sender of public keys. S2. The intelligence receiver uses the system establishment algorithm Setup (Info) to establish the system. Info is the input, which is the identity information of the intelligence receiver. After the identity information is successfully verified, the system is established and operated. The intelligence receiver is both the receiver of the intelligence and the receiver of the public key. S3. The intelligence sender uses the public key function SendPKE to generate a public key Pk and a private key Sk, keeps the private key Sk private, and sends the public key Pk to the intelligence receiver; S4. The intelligence sender selects the required transmission method for intelligence transmission, where the transmission methods include two types: a signature method without secret information and a signature method with secret information. If the intelligence sender selects a signature method without secret information, the intelligence sender uses the private key Sk generated by itself as the signature key and calls the function NoSecretSign(MessageSk) to sign the plaintext Message to generate a signature S. The system then sends the plaintext and the generated signature to the intelligence receiver, where the input of the function NoSecretSign(MessageSk) is the plaintext Message and the private key Sk, and the output is the signature S, where the signature S belongs to the signature domain and is in the form of a matrix. Each element in the matrix stores the corresponding data element, and each data element is stored in the matrix in decimal. If the intelligence sender selects a signature method with secret information, the function Embed is called. Sign(MessageSk, Secret, LenSecret) generates a signature S, and uses the differential extended steganography function DE-HSn_H(Carrier, Secret) on the signature to hide information and generate a signature S′, and sends the plaintext and the new signature S′ to the intelligence receiver, where the input of the function EmbedSign(Message, Sk, Secret, LenSecret) is the plaintext Message, the private key Sk, the secret information Secret and the length of the secret information LenSecret, and the output is the signature S, the input of the differential extended steganography function DE-HSn_H(Carrier, Secret) is the carrier Carrier and the secret information Secret, the carrier Carrier corresponds to the signature S and the secret information Secret corresponds to the information to be hidden, and the output is the new signature S′; S5. After receiving the plaintext and signature, the intelligence receiver selects the required processing method to verify the information. There are two verification methods: direct verification and verification after extracting secret information. If direct verification is selected, the direct verification function Verify(S, Message, Pk) is called for direct verification to obtain the verification result. The input of the function Verify(S, Message, Pk) is the signature S, the plaintext Message, and the public key Pk, and the output is the verification result. If verification is selected after extracting secret information, the differential extension extraction function DE-HS_n_E(S) is first called to extract the secret information. The input of the function DE-HSn_E(S) is the signature S, and the output is the secret information. Then the function Verify(S, Message, Pk) is called to obtain the verification result.

2. According to claim 1, a method for information hiding and intelligence transmission based on lattice cryptographic signature domain is characterized in that: The system establishes the algorithm Setup (Info), and the implementation process is as follows: T1, connect to the backend database; T2, the intelligence receiver or intelligence sender inputs personal identity information Info; T3, verify the personal identity information Info with the back-end database information; T4. If the verification is successful, the system of the intelligence receiver or the intelligence sender is established, the intelligence receiver database and the intelligence sender database are generated, and the system function is called. Among them, the intelligence receiver database includes a public key data table, a plaintext and signature table, and the intelligence sender database includes a private key data table. If the verification fails, the system cannot be established and the information hiding intelligence transmission method cannot be started.

3. According to claim 2, a method for information hiding and intelligence transmission based on a lattice cryptographic signature domain is characterized in that: The implementation process of the sending public key function SendPKE is as follows: D1. Connect to the backend database; D2. The system generates a random public key-private key pair; both the public key and the private key are in the form of a matrix, and the element type in the matrix is ​​a decimal number; D3. The system transmits the generated public key to the public key data table of the intelligence receiver, and stores the private key in the private key data table of the intelligence sender. The public key data table stores all public keys received by the intelligence receiver, and the private key data table stores all private keys saved by the intelligence sender.

4. According to claim 3, a method for information hiding and intelligence transmission based on lattice cryptographic signature domain is characterized in that: The implementation process of the message sender sending NoSecretSign(Message, Sk) without the signature of secret information is as follows: E1, connect to the backend database; E2. The intelligence sender selects the private key used for signing from the private key data table; E3. Enter the message to be signed; E4. The system signs the information and generates a signature S; E5. Encapsulate the message Message, signature S and other descriptive information and send them to the plaintext and signature table in the intelligence receiver's database. The other descriptive information includes the length LenSecret of the secret information. The length of the secret information of the signature information without secret information is 0.

5. According to claim 4, a method for information hiding and intelligence transmission based on lattice cryptographic signature domain is characterized in that: The direct verification function Verify(S, Message, Pk) process is as follows: F1, connect to the backend database; F2. The intelligence receiver selects the message Message and signature S to be verified from the plaintext and signature information table, and selects the public key corresponding to the signature from the public key data table; F3. The system uses the signature S to verify the information Message, obtains the verification result and outputs it.

6. According to claim 5, the information hiding intelligence transmission method based on the lattice cryptographic signature domain is characterized in that: The implementation process of the differential extended steganographic function DE_HSn_H (Carrier, Secret) is as follows, where the input carrier Carrier is the signature S and Secret is the information to be hidden: H1. Connect the signature matrices S1 and S2 of S = {S1, S2} together to form an N-dimensional square matrix. First, preprocess each element, that is, add a constant Num, Num = 128 or 256, and group the adjacent elements of each row after preprocessing. Each row has groups, total groups, N is the dimension of the square matrix formed by splicing matrices s1 and S2 together end to end, calculate the difference h and mean i of each group, form the difference matrix H and mean matrix I, and draw a difference distribution histogram; H2. Convert the hidden information Secret into binary information in the format of ASCII code, count the length of the binary information LenSecret, and select the group of secret information with smaller absolute difference value and expandable M bits of all 1 from the difference histogram in the raster scanning order, where M is a constant with a limited value range, M=1, 2, 4 or 8, determine the maximum absolute value Delta of the selected difference, and shift the histogram accordingly; retain the two LSB valid information of the four corner elements of the shifted matrix, where LSB represents the least significant bit, and retain them at the end of the hidden information Secret in order to generate Secret′; convert Delta into an 8-bit binary number, and embed it into the lowest two LSBs of the four corner elements in order, and then split Secret′ into groups of M bits, where M is a constant with a limited value range, M=1, 2, 4 or 8, and embed a secret information group into each selected difference group in the raster scanning order; H3. After embedding, the generated signature is processed again, that is, Num is added to the value of each element to generate a signature S′ with secret information; H4. The system sends the newly generated signature field and plain text to the plain text and signature table in the intelligence recipient's database.

7. The information hiding intelligence transmission method based on lattice cryptographic signature domain according to claim 6 is characterized in that: The sender of the message sends the function EmbedSign(Message, Sk, Secret, LenSecret) in a signature method containing secret information. The implementation process is as follows: G1, connect to the backend database; G2. The intelligence sender selects the private key used for signing from the private key data table; G3. The sender of the information enters the message to be signed; G4. Sign the message Message through the system and generate a signature S; G5. The intelligence sender inputs the secret information Secret and the length of the secret information LenSecret to be transmitted, and uses the function DE-HSn_H (Carrier, Secret) to embed the information in the obtained signature S to obtain a new signature S′, where the signature S is used as the carrier Carrier; G6. The system encapsulates the message Message, the new signature S′ and other descriptive information and sends them to the plaintext and signature table in the intelligence receiver's database. The other descriptive information includes the secret information length LenSecret, and the length of the secret information embedded in the secret information is not 0.

8. The information hiding intelligence transmission method based on lattice cryptographic signature domain according to claim 7 is characterized in that: The implementation process of the differential extension extraction function DE_HSn_E(S) is as follows: N1. The intelligence receiver selects a signature S′ embedded with secret information from the plaintext and signature table; N2. The system preprocesses the elements in the signature S′. The signature S′ is in the form of a square matrix. Num is subtracted from each element in the square matrix. Two LSBs are extracted from the four corner elements in the square matrix of the signature S′ in order, and the two LSBs are concatenated to form Delta. The difference matrix H′ and the mean matrix I′ are calculated. N3. According to Delta, determine the difference range of the embedded secret information, determine the grouping of the embedded secret information according to the raster scanning order, extract and splice the secret information according to the differential expansion recovery formula according to the extension bit number M, and form Secret′. After the extraction, perform a histogram reverse shift operation on the grouping and restore the histogram; restore the restored grouping to the signature matrix after the histogram reverse shift to generate S″; N4. The system intercepts the last eight bits of binary information of Secret′, and the rest is the secret information Secret. The last eight LSB information is restored to S″ in order to generate the original signature S; N5. The system groups the secret information Secret by 8 bits, converts it into decimal ASCII code, and returns the embedded secret information.

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