A Hybrid Covert Communication Method and Related Devices for the Internet of Things

Abstract

The present application discloses a hybrid covert communication method and related devices for the Internet of Things, which relates to the field of covert communication technology. The method includes: determining whether the number of bits of the secret information to be covertly transmitted is greater than a preset number of bits. If not, based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sorting multiple CoAP data packets so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted. If so, based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sorting multiple CoAP data packets, and embedding the secret information of the first number of bits in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted. The present application can perform covert communication based on the CoAP network protocol, and can ensure the robustness, anti-detection performance, and high-capacity performance of covert communication.

Description

Technical Field

[0001] This application relates to the field of covert communication technologies, and particularly to a hybrid covert communication method and related devices for the Internet of Things. Background Art

[0002] For the Internet of Things, communication is a key technology in its development process. Similar to the Internet, in the communication process of the Internet of Things, network protocols also play a crucial role. Countless network nodes in the Internet of Things communicate through network protocols. Network protocols with various characteristics, a considerable number of network data packets, and redundant parts in the network data packets all provide the feasibility for the construction of covert channels.

[0003] CoAP (Constrained Application Protocol) is one of the most widely used Internet of Things communication protocols currently. CoAP is a transport protocol specifically designed for constrained nodes and constrained networks in the Internet of Things. It is based on the REST architecture and uses the "request / response" mechanism for information exchange. It defines CoAP data packets of 4 different message types, and a CoAP data packet consists of a fixed header, a variable-length Token, optional Options, and an optional payload. The length of the CoAP data packet is flexible and variable, and these characteristics provide the feasibility for covert communication in the Internet of Things environment based on this CoAP network protocol. Summary of the Invention

[0004] The purpose of this application is to provide a hybrid covert communication method and related devices for the Internet of Things, which can perform covert communication based on the CoAP network protocol.

[0005] To achieve the above purpose, this application provides the following solutions:

[0006] In a first aspect, this application provides a hybrid covert communication method for the Internet of Things. The hybrid covert communication method for the Internet of Things includes:

[0007] Judge whether the number of bits of the secret information to be covertly transmitted is greater than a preset number of bits;

[0008] If not, then based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sort multiple CoAP data packets so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted;

[0009] If so, based on the correspondence between the length intervals where the lengths of the preset CoAP data packets are located and the secret information, sort the multiple CoAP data packets, and embed the secret information of the first digit in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted; where the first digit is equal to the difference between the total number of digits of the secret information to be secretly transmitted and the preset number of digits.

[0010] Optionally, before sorting the multiple CoAP data packets based on the correspondence between the length intervals where the lengths of the preset CoAP data packets are located and the secret information, the hybrid stealth communication method for the Internet of Things further includes:

[0011] According to the CoAP data packet length distribution, divide the CoAP data packet lengths into i + 1 length intervals; where i = 2 k -1, and k is a positive integer;

[0012] Perform permutations and combinations on the k-bit secret information to obtain i + 1 combinations;

[0013] Set each length interval to correspond to one combination to obtain the correspondence between the length intervals where the lengths of the preset CoAP data packets are located and the secret information.

[0014] Optionally, sorting the multiple CoAP data packets based on the correspondence between the length intervals where the lengths of the preset CoAP data packets are located and the secret information, so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted, specifically includes:

[0015] Select the first k-bit secret information of the secret information to be secretly transmitted as the secret information to be embedded;

[0016] Based on the secret information to be embedded and the correspondence between the length intervals where the lengths of the preset CoAP data packets are located and the secret information, determine the length interval corresponding to the secret information to be embedded;

[0017] Select a CoAP data packet with a packet length within the length interval corresponding to the secret information to be embedded from the multiple CoAP data packets as the selected data packet;

[0018] Judge whether the number of digits of the secret information to be secretly transmitted in the current iteration is 0;

[0019] If not, remove the secret information to be embedded from the secret information to be secretly transmitted in the current iteration to obtain the secret information to be secretly transmitted in the next iteration, and return to the step of "selecting the first k-bit secret information of the secret information to be secretly transmitted as the secret information to be embedded";

[0020] If so, sort all the selected data packets in the selected order to sort multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted.

[0021] Optionally, embed the secret information of the first digit in the sorted multiple CoAP data packets, specifically including:

[0022] Among the sorted multiple CoAP data packets, select the CoAP data packet with the packet length in the largest length interval as the data packet to be embedded;

[0023] Embed the secret information of the first digit in the variable field of the data packet to be embedded.

[0024] Optionally, embed the secret information of the first digit in the variable field of the data packet to be embedded, specifically including:

[0025] For each data packet to be embedded, according to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded. The secret information embedded in all the data packets to be embedded forms the secret information of the first digit;

[0026] Among them, the number of bits of the embedding information b is a random number within the range of [b min , b max , b min is the minimum value, b max is the maximum value, 0 ≤ b min ≤ b max , b min ≤ b max ≤ Min(V max , L max ), V max is the theoretical maximum number of bits of the embedding information, and L max is the actual maximum number of bits of the embedding information.

[0027] Optionally, according to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded, specifically including: write the number of bits of the embedding information in the optional Option of the data packet to be embedded, and embed the secret information in the optional payload of the data packet to be embedded; among them, the optional Option and the optional payload correspond to each other.

[0028] Optionally, after making the sorted multiple CoAP data packets form the secret information to be covertly transmitted, the hybrid covert communication method for the Internet of Things further includes:

[0029] Add a start boundary identifier in front of multiple sorted CoAP data packets, and add an end boundary identifier behind the multiple sorted CoAP data packets to form a data packet to be transmitted, and send the data packet to be transmitted to the receiving end; wherein, both the start boundary identifier and the end boundary identifier include n CoAP data packets with the same message type, n is a positive integer greater than 1, and the message types include messages that require confirmation, messages that do not require confirmation, confirmation reply messages, and reset messages.

[0030] Optionally, the selection methods of i and b include: if the communication network environment is complex or there is a security threat, then reduce i and b; if the demand for the embedding amount of the secret information is large, then increase i and b.

[0031] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor executes the computer program to implement the hybrid covert communication method for the Internet of Things described in any one of the above.

[0032] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the hybrid covert communication method for the Internet of Things described in any one of the above.

[0033] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0034] The present application provides a hybrid covert communication method for the Internet of Things and related devices. The method includes: determining whether the number of bits of the secret information to be covertly transmitted is greater than a preset number of bits. If not, then based on the correspondence between the preset length range of the CoAP data packet length and the secret information, sort multiple CoAP data packets so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted. If so, then based on the correspondence between the preset length range of the CoAP data packet length and the secret information, sort multiple CoAP data packets, and embed the secret information of the first number of bits in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted, wherein the first number of bits is equal to the difference between the total number of bits of the secret information to be covertly transmitted and the preset number of bits. The present application can perform covert communication based on the CoAP network protocol, and can ensure the robustness and anti-detection of covert communication through the time covert channel method of embedding secret information based on different combinations of CoAP data packet lengths. At the same time, the storage covert channel method of embedding secret information in the variable fields of CoAP data packets with a certain length range of packet lengths achieves the high-capacity performance of the covert channel. Description of the Drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 It is an application environment diagram of a hybrid covert communication method for the Internet of Things provided in Embodiment 1 of the present application.

[0037] Figure 2 It is a schematic flowchart of a hybrid covert communication method for the Internet of Things provided in Embodiment 1 of the present application.

[0038] Figure 3 It is a schematic structural diagram of a computer device provided in Embodiment 2 of the present application. Detailed implementation manners

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0040] Embodiment 1

[0041] The hybrid covert communication method for the Internet of Things provided in the embodiments of the present application can be applied, for example, as Figure 1In the application environment shown. Among them, the terminal communicates with the server through the network. The data storage system can store the data that the server needs to process. The data storage system can be set separately, integrated on the server, or placed on the cloud or other servers. The terminal can send an embedding request to be processed (used to request to embed the secret information to be secretly transmitted in the CoAP data packet) to the server. After receiving the embedding request to be processed, for the embedding request to be processed, the server determines whether the number of bits of the secret information to be secretly transmitted is greater than the preset number of bits; if not, based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sort multiple CoAP data packets so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted; if so, based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sort multiple CoAP data packets, and embed the secret information of the first number of bits in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted; where the first number of bits is equal to the difference between the total number of bits of the secret information to be secretly transmitted and the preset number of bits. The server can feedback the embedding result for the embedding request obtained to the terminal.

[0042] In addition, in some embodiments, the hybrid stealth communication method for the Internet of Things can also be implemented by the server or the terminal alone. For example, the terminal can directly process the embedding request to be processed, or the server can obtain the embedding request to be processed from the data storage system and process the embedding request to be processed.

[0043] Among them, the terminal can be, but is not limited to, various desktop computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The server can be implemented by an independent server or a server cluster composed of multiple servers, and can also be a cloud server.

[0044] In an exemplary embodiment, as Figure 2 shown, a hybrid stealth communication method for the Internet of Things is provided. This method is executed by a computer device, and can be specifically executed by a computer device such as a terminal or a server alone, or jointly executed by the terminal and the server. In the embodiments of the present application, taking this method as applied to Figure 1 the server in it as an example for description, it includes the following steps.

[0045] Step S1, determine whether the number of bits of the secret information to be secretly transmitted is greater than the preset number of bits.

[0046] Step S2. If the answer is no, then sort the multiple CoAP data packets based on the corresponding relationship between the length intervals where the preset CoAP data packet lengths are located and the secret information, so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted.

[0047] Step S3. If the answer is yes, then sort the multiple CoAP data packets based on the corresponding relationship between the length intervals where the preset CoAP data packet lengths are located and the secret information, and embed the secret information of the first digit in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be secretly transmitted; where the first digit is equal to the difference between the total number of digits of the secret information to be secretly transmitted and the preset number of digits.

[0048] By implementing the above Steps S1 to S3, the secret information to be secretly transmitted in this embodiment is secretly transmitted by mixing two methods: the time hidden channel and the storage hidden channel. The time hidden channel method embeds the secret information through a combination sequence of CoAP data packets of different lengths. The storage hidden channel method directly embeds the secret information into the variable fields of CoAP data packets whose packet lengths are in a certain length interval. If the amount of secret information to be embedded is less than the preset number of digits, only the time hidden channel method can be selected for embedding, that is, the direct field embedding amount is zero. If the amount of secret information to be embedded is greater than the preset number of digits, the time hidden channel and the storage hidden channel can be used simultaneously for embedding. The time hidden channel method of embedding the secret information through a combination sequence of CoAP data packets of different lengths can ensure the robustness and anti-detection ability of the covert communication. This is because the length of the CoAP data packet is not changed, only the CoAP data packets are sorted, and as long as it satisfies being in a certain length interval during sorting, CoAP data packets of different lengths will represent the same secret information, which is difficult to distinguish from the original CoAP data packets. At the same time, the storage hidden channel method of embedding the secret information into the variable fields of CoAP data packets whose packet lengths are in a certain length interval achieves the high-capacity performance of the hidden channel.

[0049] The preset number of digits is (m - 2n) × k bits, where m is the number of CoAP data packets available for hiding the secret information, n is the number of CoAP data packets used as boundary identifiers, and k is the number of bits of secret information that a CoAP data packet can hide.

[0050] The time hidden channel method is: According to the CoAP data packet length distribution, set i length boundaries l j , where j = 1, 2,..., i, i = 2 k -1, k is a positive integer, that is, the CoAP data packet length l is divided into i + 1 length intervals, which are: l ≤ l1, l1 < l ≤ l2, l2 < l ≤ l3,..., lj-1 <l≤l j , …, l i-1 <l≤l i , l>l i , so that all CoAP data packets can be divided into i + 1 length categories. Then each CoAP data packet can represent k bits of secret information according to the length interval it belongs to. That is, each CoAP data packet can hide k bits of secret information. For example, if three length boundaries l1, l2, and l3 are set for the CoAP data packet length, the CoAP data packet length l is divided into 4 length intervals, namely: l≤l1, l1<l≤l2, l2<l≤l3, l>l3. Then each CoAP data packet can represent 2 bits of secret information according to the length interval it belongs to, corresponding to "00", "01", "10", "11" respectively. If the length of a certain CoAP data packet is between l1 and l2, that is, l1<l≤l2, then this CoAP data packet is equivalent to carrying two bits of secret information "01".

[0051] The storage steganographic channel method is as follows: To increase the capacity of the steganographic channel, that is, the embedding amount of secret information, select CoAP data packets with lengths in the largest length interval (i.e., l>l i ), and directly embed the secret information in the variable fields of these CoAP data packets. The embedding amount is set according to the embedding requirements. Specifically, write the number of embedded information bits b into field s1, and embed the corresponding number of bits of secret information into field s2. Field s1 is an optional Option, and field s2 is an optional payload. The embedding amount b each time is a random number not exceeding the maximum value V max represented by field s1. V max can be understood as the maximum number of bits of information that can be written into field s1 theoretically, that is, V max is the theoretical maximum embedding information bit number. At the same time, the peak value of the embedding amount b cannot exceed the actual maximum bit number L max represented by this field of the original traffic data packet. L max can be understood as the maximum number of bits of information written into field s1 during actual use, that is, L max is the actual maximum embedding information bit number. That is to say, the range of b is [b min , b max , where the value range of b min is 0≤b min ≤b max , and the value range of b max is b min ≤b max ≤Min(V max , L max ). When b min and b maxWhen both are set to zero, the direct embedding amount of the data packet field is zero, which is equivalent to suspending the covert communication of the storage covert channel at this time, but does not affect the normal operation of the time covert channel. When the covert channel has a high-capacity requirement, b min and b max can be appropriately increased within their value ranges.

[0052] At this time, before sorting multiple CoAP data packets based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, the hybrid covert communication method for the Internet of Things in this embodiment further includes:

[0053] (1) According to the CoAP data packet length distribution, divide the CoAP data packet length into i + 1 length intervals, where i = 2 k -1, and k is a positive integer.

[0054] (2) Perform permutations and combinations on the k-bit secret information to obtain i + 1 combinations.

[0055] (3) Set each length interval to correspond to one combination to obtain the correspondence between the length interval where the preset CoAP data packet length is located and the secret information.

[0056] At this time, in S2, based on the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, sort the multiple CoAP data packets so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted, specifically including:

[0057] (1) Select the first k-bit secret information of the secret information to be covertly transmitted as the secret information to be embedded.

[0058] (2) Based on the secret information to be embedded and the correspondence between the length interval where the preset CoAP data packet length is located and the secret information, determine the length interval corresponding to the secret information to be embedded.

[0059] (3) Select a CoAP data packet whose packet length is within the length interval corresponding to the secret information to be embedded from the multiple CoAP data packets as the selected data packet.

[0060] (4) Determine whether the number of bits of the secret information to be covertly transmitted in the current iteration is 0.

[0061] (5) If not, remove the secret information to be embedded from the secret information to be covertly transmitted in the current iteration to obtain the secret information to be covertly transmitted in the next iteration, and return to the step of "selecting the first k-bit secret information of the secret information to be covertly transmitted as the secret information to be embedded".

[0062] (6) If so, sort all the selected data packets in the order of selection to sort multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information to be covertly transmitted.

[0063] At this time, in S3, based on the corresponding relationship between the length interval where the preset CoAP data packet length is located and the secret information, sort the multiple CoAP data packets, specifically including:

[0064] (1) Select secret information with a preset number of bits from the secret information to be covertly transmitted, and select the first k bits of the secret information with the preset number of bits as the secret information to be embedded.

[0065] (2) Based on the secret information to be embedded and the corresponding relationship between the length interval where the preset CoAP data packet length is located and the secret information, determine the length interval corresponding to the secret information to be embedded.

[0066] (3) Select a CoAP data packet whose packet length is within the length interval corresponding to the secret information to be embedded from the multiple CoAP data packets as the selected data packet.

[0067] (4) Determine whether the number of bits of the secret information with the preset number of bits in the current iteration is 0.

[0068] (5) If not, remove the secret information to be embedded from the secret information with the preset number of bits in the current iteration to obtain the secret information with the preset number of bits in the next iteration, and return to the step of "selecting the first k bits of the secret information with the preset number of bits as the secret information to be embedded".

[0069] (6) If so, sort all the selected data packets in the order of selection to sort multiple CoAP data packets, so that the sorted multiple CoAP data packets form the secret information with the preset number of bits.

[0070] At this time, in S3, embed the secret information of the first digit in the sorted multiple CoAP data packets, specifically including:

[0071] (1) In the sorted multiple CoAP data packets, select the CoAP data packet with the packet length in the largest length interval as the data packet to be embedded.

[0072] (2) Embed the secret information of the first digit in the variable field of the data packet to be embedded.

[0073] Embed the secret information of the first digit in the variable field of the data packet to be embedded, specifically including: for each data packet to be embedded, according to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded. The secret information embedded in all data packets to be embedded constitutes the secret information of the first digit. Among them, the number of bits of the embedding information b is a random number within the range of [b min ,b max , b min is the minimum value, b max is the maximum value, 0 ≤ b min ≤ b max , b min ≤ b max ≤ Min(V max , L max ), V max is the theoretical maximum number of bits of embedding information, and L max is the actual maximum number of bits of embedding information.

[0074] Among them, according to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded, specifically including: write the number of bits of the embedding information in the optional Option of the data packet to be embedded, and embed the secret information in the optional payload of the data packet to be embedded, where the optional Option and the optional payload correspond to each other.

[0075] At this time, multiple sorted CoAP data packets form the secret information to be covertly transmitted.

[0076] In this embodiment, the CoAP data packets of four message types are set as P1, P2, P3, and P4 respectively. Select a combination sequence of n (preferably, n ≥ 4) consecutive CoAP data packets of one of the message types as the boundary identification sequence. For example, specify a combination sequence of four consecutive P1 data packets as the start boundary identification for the start of covert communication and the end boundary identification for the end of covert communication. If four consecutive P1 data packets appear in the original traffic data packet, adjust the data packet sequence so that data packets of other message types are inserted into these four consecutive P1 data packets to avoid the appearance of a consecutive combination sequence identical to the boundary identification sequence. When the start boundary identification composed of n consecutive CoAP data packets of a certain same message type appears, covert communication starts, and when the end boundary identification composed of n consecutive CoAP data packets of a certain same message type appears, covert communication ends.

[0077] At this time, after making multiple CoAP data packets after sorting form the secret information to be covertly transmitted, the hybrid covert communication method for the Internet of Things in this embodiment further includes: adding a start boundary identifier in front of the multiple sorted CoAP data packets, and adding an end boundary identifier behind the multiple sorted CoAP data packets to form a data packet to be transmitted, and sending the data packet to be transmitted to the receiving end. Among them, both the start boundary identifier and the end boundary identifier include n CoAP data packets with the same message type, n is a positive integer greater than 1, and the message types include messages that require confirmation, messages that do not require confirmation, confirmation response messages, and reset messages.

[0078] In this embodiment, the selection methods of i and b include: if the communication network environment is complex or there are security threats, then reduce i and b; if the demand for the embedding amount of secret information is large, then increase i and b.

[0079] This embodiment can adjust parameters according to the mobile network situation or the embedding amount requirement to achieve the self-adaptability of security requirements. If the communication network environment is complex or there are security threats, the value of i can be appropriately reduced and the value of b can also be reduced. In this way, the robustness and anti-detection ability of the covert channel can be improved. This is because the smaller the value of i, the more CoAP data packets available for the same secret information, and the stronger the concealment; if the demand for the embedding amount of secret information is large, the value of i can be appropriately increased and the value of b can also be appropriately increased. In this way, the number of bits of secret information carried by each CoAP data packet of different lengths will increase, especially the direct embedding amount of secret information in the CoAP data packets in the maximum length interval will also become larger.

[0080] This embodiment provides a hybrid covert communication method based on the Internet of Things communication protocol CoAP. In the Internet of Things environment using the CoAP network protocol, the secret information to be covertly transmitted is covertly transmitted by mixing the time covert channel and the storage covert channel. The time covert channel method embeds the secret information through the combination sequence of CoAP data packets of different lengths, and the storage covert channel method directly embeds the secret information into the variable fields of CoAP data packets whose packet lengths are in a certain length interval. This method can not only ensure the robustness, anti-detection ability and high capacity of the covert channel, but also adjust parameters according to the mobile network situation or the embedding amount requirement to achieve the self-adaptability of security requirements.

[0081] The present application also provides an application scenario, which applies the above-mentioned hybrid covert communication method for the Internet of Things. Specifically, the hybrid covert communication method for the Internet of Things provided in this embodiment can be applied in a covert communication scenario. The covert communication scenario includes a secret information embedding link and a communication link. The secret information embedding link is used to embed the secret information to be covertly transmitted in the CoAP data packet, and the communication link is used to send the CoAP data packet embedded with the secret information to be covertly transmitted to the receiving end. The hybrid covert communication method for the Internet of Things provided in this embodiment belongs to the secret information embedding link.

[0082] Embodiment 2

[0083] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 3 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a hybrid covert communication method for the Internet of Things.

[0084] Those skilled in the art can understand that Figure 3 the structure shown in

[0085] is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0086] Embodiment 3

[0087] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which, when executed by a processor, implements the hybrid covert communication method for the Internet of Things in Embodiment 1.

[0088] Embodiment 4

[0089] In an exemplary embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the hybrid covert communication method for the Internet of Things in Embodiment 1.

[0090] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0091] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0092] Specific examples are used in this article to elaborate on the principles and implementation manners of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A hybrid covert communication method for the Internet of Things, characterized in that The hybrid covert communication method for the Internet of Things includes: Determine whether the number of bits of the secret information to be covertly transmitted is greater than a preset number of bits; If not, based on the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information, sort multiple CoAP packets so that the sorted multiple CoAP packets form the secret information to be covertly transmitted; If so, based on the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information, sort multiple CoAP packets, and embed the secret information of the first number of bits in the sorted multiple CoAP packets so that the sorted multiple CoAP packets form the secret information to be covertly transmitted; wherein, the first number of bits is equal to the difference between the total number of bits of the secret information to be covertly transmitted and the preset number of bits; Embedding the secret information of the first number of bits in the sorted multiple CoAP packets specifically includes: among the sorted multiple CoAP packets, select the CoAP packet with the packet length in the largest length interval as the packet to be embedded; embed the secret information of the first number of bits in the variable field of the packet to be embedded.

2. The hybrid covert communication method for the Internet of Things according to claim 1, characterized in that Before sorting multiple CoAP packets based on the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information, the hybrid covert communication method for the Internet of Things further includes: According to the CoAP packet length distribution, the CoAP packet length is divided into i + 1 length intervals; where i = 2 k - 1, and k is a positive integer; Perform permutations and combinations on the k-bit secret information to obtain i + 1 combinations; Set each length interval to correspond to one combination to obtain the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information.

3. The hybrid covert communication method for the Internet of Things according to claim 1, characterized in that Sorting multiple CoAP packets based on the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information so that the sorted multiple CoAP packets form the secret information to be covertly transmitted specifically includes: Select the first k-bit secret information of the secret information to be covertly transmitted as the secret information to be embedded; Based on the secret information to be embedded and the correspondence between the length intervals where the preset CoAP packet lengths are located and the secret information, determine the length interval corresponding to the secret information to be embedded; Among multiple CoAP packets, select a CoAP packet with a packet length within the length interval corresponding to the secret information to be embedded as the selected packet; Determine whether the number of bits of the secret information to be covertly transmitted in the current iteration is 0; If not, remove the secret information to be embedded from the secret information to be covertly transmitted in the current iteration to obtain the secret information to be covertly transmitted in the next iteration, and return to the step of "selecting the first k-bit secret information of the secret information to be covertly transmitted as the secret information to be embedded"; If so, sort all the selected packets in the order of selection to sort multiple CoAP packets so that the sorted multiple CoAP packets form the secret information to be covertly transmitted.

4. The hybrid covert communication method for the Internet of Things according to claim 2, characterized in that Embedding the secret information of the first number of bits in the variable field of the packet to be embedded specifically includes: For each data packet to be embedded, according to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded, and the secret information embedded in all data packets to be embedded forms the secret information of the first number of bits; Among them, the number of embedded information bits b is a random number within the range of [b min , b max , b min is the minimum value, b max is the maximum value, 0 ≤ b min ≤ b max , b min ≤ b max ≤ Min(V max , L max ), V max is the theoretical maximum number of embedded information bits, and L max is the actual maximum number of embedded information bits.

5. The hybrid covert communication method for the Internet of Things according to claim 4, characterized in that According to the number of bits of the embedding information of the data packet to be embedded, embed the secret information in the variable field of the data packet to be embedded, specifically including: write the number of bits of the embedding information in the optional Option of the data packet to be embedded, and embed the secret information in the optional payload of the data packet to be embedded; wherein, the optional Option and the optional payload correspond to each other.

6. The hybrid covert communication method for the Internet of Things according to claim 1, characterized in that After the sorted multiple CoAP data packets form the secret information to be covertly transmitted, the hybrid covert communication method for the Internet of Things further includes: Add a start boundary identifier in front of the sorted multiple CoAP data packets, and add an end boundary identifier behind the sorted multiple CoAP data packets to form a data packet to be transmitted, and send the data packet to be transmitted to the receiving end; wherein, both the start boundary identifier and the end boundary identifier include n CoAP data packets with the same message type, n is a positive integer greater than 1, and the message types include messages that require confirmation, messages that do not require confirmation, confirmation reply messages, and reset messages.

7. The hybrid covert communication method for the Internet of Things according to claim 4, characterized in that The selection method of i and b includes: if the communication network environment is complex or there is a security threat, then reduce i and b; if the demand for the embedding amount of the secret information is large, then increase i and b.

8. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the hybrid covert communication method for the Internet of Things according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the hybrid covert communication method for the Internet of Things according to any one of claims 1-7.

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