Hybrid covert communication method for Internet of Things and related device

Abstract

The invention discloses a hybrid covert communication method for the Internet of Things and a related device, and relates to the technical field of covert communication, and the method comprises the steps: judging whether the digit of secret information to be transmitted in a concealed manner is greater than a preset digit, and if not, transmitting the secret information to be transmitted in a concealed manner based on the corresponding relation between a length interval where a preset CoAP data packet length is located and the secret information; sorting the plurality of CoAP data packets to enable the plurality of sorted CoAP data packets to form secret information to be transmitted in a hidden manner, if so, sorting the plurality of CoAP data packets based on a corresponding relationship between a length interval where a preset CoAP data packet length is located and the secret information, and embedding the secret information of a first digit in the plurality of sorted CoAP data packets, according to the method and the device, the covert communication can be carried out based on the CoAP network protocol, and the robustness, the detection resistance and the high capacity performance of the covert communication can be ensured.

Description

Technical Field

[0001] The present application relates to the field of covert communication technology, and in particular 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. Like the Internet, network protocols also play a vital role in the communication process of the Internet of Things. Countless network nodes in the Internet of Things communicate through network protocols. The unique network protocols, the considerable number of network data packets, and the redundant parts in the network data packets all provide feasibility for the construction of covert channels.

[0003] CoAP (Constrained Application Protocol) is one of the most widely used IoT communication protocols. CoAP is a transmission protocol designed specifically for constrained nodes and networks in the IoT. It is based on the REST architecture and uses a "request / response" mechanism for information exchange. It defines four different message types of CoAP packets, and the CoAP packet consists of a fixed header, a variable-length token, an optional option, and an optional payload. The length of the CoAP packet is flexible and changeable. These features make it feasible to conduct covert communication in the IoT environment based on the 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 objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a hybrid covert communication method for the Internet of Things, the hybrid covert communication method for the Internet of Things comprising:

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

[0008] If not, based on the correspondence between the preset CoAP data packet length interval and the secret information, the multiple CoAP data packets are sorted so that the sorted multiple CoAP data packets constitute the secret information to be concealedly transmitted;

[0009] If so, based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, multiple CoAP data packets are sorted, and the first digit of the secret information is embedded in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly; wherein the first digit is equal to the difference between the total number of bits of the secret information to be transmitted covertly and the preset number of bits.

[0010] Optionally, before sorting the multiple CoAP data packets based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, the hybrid covert communication method for the Internet of Things further includes:

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

[0012] Arrange and combine the k bits of secret information to obtain i+1 combinations;

[0013] Each length interval is set to correspond to a combination, and the corresponding relationship between the length interval of the preset CoAP data packet length and the secret information is obtained.

[0014] Optionally, based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, multiple CoAP data packets are sorted so that the sorted multiple CoAP data packets constitute the secret information to be covertly transmitted, specifically including:

[0015] Select the first k bits of the secret information to be transmitted covertly as the secret information to be embedded;

[0016] Determine the length interval corresponding to the secret information to be embedded based on the correspondence between the secret information to be embedded, the preset CoAP data packet length, and the secret information;

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

[0018] Determine whether the number of bits of the secret information to be concealedly transmitted in the current iteration is 0;

[0019] If not, the secret information to be embedded is removed from the secret information to be concealedly transmitted in the current iteration to obtain the secret information to be concealedly transmitted in the next iteration, and the process returns to the step of "selecting the first k bits of the secret information to be concealedly transmitted as the secret information to be embedded";

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

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

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

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

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

[0025] For each data packet to be embedded, according to the number of embedded information bits 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 the data packets to be embedded constitutes the secret information of the first digit;

[0026] Among them, the number of embedded information bits b is in [b min , b max ]A random number in the range 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, L max is the actual maximum number of embedded information bits.

[0027] Optionally, according to the number of embedded information bits of the data packet to be embedded, secret information is embedded in the variable field of the data packet to be embedded, specifically including: writing the number of embedded information bits in the optional Option of the data packet to be embedded, and embedding secret information in the optional load of the data packet to be embedded; wherein the optional Option and the optional load correspond to each other.

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

[0029] A start boundary identifier is added in front of the sorted multiple CoAP data packets, and an end boundary identifier is added after the sorted multiple CoAP data packets to form a data packet to be transmitted, and the data packet to be transmitted is sent to the receiving end; wherein, the start boundary identifier and the end boundary identifier both include n CoAP data packets of the same message type, n is a positive integer greater than 1, and the message types include confirmation required messages, confirmation not required messages, confirmation response messages and reset messages.

[0030] Optionally, the method for selecting i and b includes: if the communication network environment is complex or there is a security threat, then reducing i and b; if the amount of secret information embedded is required to be large, then increasing i and b.

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

[0032] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the hybrid covert communication methods for the Internet of Things described above.

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

[0034] The present application provides a hybrid covert communication method and related device for the Internet of Things, the method comprising: determining whether the number of bits of secret information to be transmitted covertly is greater than a preset number of bits, if not, sorting multiple CoAP packets based on the correspondence between the length interval of the preset CoAP packet length and the secret information, so that the sorted multiple CoAP packets constitute the secret information to be transmitted covertly, if so, sorting multiple CoAP packets based on the correspondence between the length interval of the preset CoAP packet length and the secret information, and embedding the first digit of secret information in the sorted multiple CoAP packets, so that the sorted multiple CoAP packets constitute the secret information to be transmitted covertly, wherein the first digit is equal to the difference between the total number of bits of the secret information to be transmitted covertly 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 performance of covert communication by embedding secret information in a time covert channel method based on a combined sequence of CoAP packets of different lengths, and at the same time achieve high capacity performance of the covert channel by embedding secret information in a variable field of a CoAP packet whose packet length is in a certain length interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0037] Figure 2 A flow chart of a hybrid covert communication method for the Internet of Things provided in Example 1 of the present application.

[0038] Figure 3 A schematic diagram of the structure of a computer device provided in Example 2 of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] Example 1

[0041] The hybrid covert communication method for the Internet of Things provided in the embodiment of the present application can be applied to 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 up separately, integrated on the server, or placed on the cloud or other servers. The terminal can send a pending embedding request (used to request to embed the secret information to be transmitted covertly in the CoAP data packet) to the server. After the server receives the pending embedding request, for the pending embedding request, the server determines whether the number of bits of the secret information to be transmitted covertly is greater than the preset number of bits; if not, based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, the multiple CoAP data packets are sorted, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly; if so, based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, the multiple CoAP data packets are sorted, and the first number of secret information is embedded in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly; wherein the first number is equal to the difference between the total number of bits of the secret information to be transmitted covertly and the preset number of bits. The server can feedback the embedding result obtained for the embedding request to the terminal.

[0042] In addition, in some embodiments, the hybrid covert communication method for the Internet of Things can also be implemented independently by a server or a terminal. For example, the terminal can directly process the pending embedded request, or the server can obtain the pending embedded request from the data storage system and process the pending embedded request.

[0043] The terminals may be, but are not limited to, various desktop computers, laptops, smart phones, tablet computers, IoT devices and portable wearable devices. IoT devices may be smart speakers, smart TVs, smart air conditioners, smart car-mounted devices, etc. Portable wearable devices may be smart watches, smart bracelets, head-mounted devices, etc. The server may be implemented as an independent server or a server cluster consisting of multiple servers, or a cloud server.

[0044] In an exemplary embodiment, Figure 2 As shown, a hybrid covert communication method for the Internet of Things is provided. The method is executed by a computer device, and specifically can be executed by a computer device such as a terminal or a server alone, or can be executed by a terminal and a server together. In the embodiment of the present application, the method is applied to Figure 1 The following steps are used to illustrate the server in the example.

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

[0046] Step S2: If not, based on the correspondence between the preset CoAP data packet length interval and the secret information, the multiple CoAP data packets are sorted so that the sorted multiple CoAP data packets constitute the secret information to be concealedly transmitted.

[0047] Step S3, if yes, then based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, multiple CoAP data packets are sorted, and the first digit of the secret information is embedded in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly; wherein the first digit is equal to the difference between the total number of bits of the secret information to be transmitted covertly and the preset number of bits.

[0048] By implementing the above steps S1 to S3, the secret information to be covertly transmitted in this embodiment is covertly transmitted by mixing the time covert channel and the storage covert channel. The time covert channel method is to embed the secret information through a combined sequence of CoAP packets of different lengths. The storage covert channel method is to directly embed the secret information into the variable field of the CoAP packets whose packet length is in a certain length interval. If the amount of secret information embedded is less than the preset number of bits, only the time covert channel method can be selected for embedding, that is, the direct field embedding amount is zero; if the amount of secret information embedded is greater than the preset number of bits, the time covert channel and the storage covert channel can be mixed and embedded at the same time. The time covert channel method for embedding secret information based on the combined sequence of CoAP packets of different lengths can ensure the robustness and anti-detection performance of covert communication. This is because the length of the CoAP packet is not changed, but the CoAP packet is sorted, and when sorting, as long as it is in a certain length interval, the CoAP packets of different lengths will represent the same secret information, which is difficult to distinguish from the original CoAP packet. At the same time, the storage covert channel method of embedding secret information in the variable field of the CoAP packet whose packet length is in a certain length interval achieves the high capacity performance of the covert channel.

[0049] The preset number of bits is (m-2n)×k bits, where m is the number of CoAP packets that can be used to hide secret information, n is the number of CoAP packets used as boundary markers, and k is the number of bits of secret information that can be hidden in a CoAP packet.

[0050] The time covert channel method is: according to the distribution of CoAP packet length, set i length boundaries l for the CoAP packet length 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≤l 1 , l1 <l≤l 2 , l 2 <l≤l 3 ,…,l j-1 <l≤l j ,…,l i-1 <l≤l i , l>l i , so that all CoAP packets can be divided into i+1 length categories, then each CoAP packet can represent k bits of secret information according to its length interval, that is, each CoAP packet can hide k bits of secret information. For example, set 3 length boundaries for the CoAP packet length l 1 , l 2 , l 3 , then the CoAP data packet length l is divided into 4 length intervals, namely: l≤l 1 , l 1 <l≤l 2 , l 2 <l≤l 3 , l>l 3 , then each CoAP packet can represent 2 bits of secret information according to its length range, which correspond to "00", "01", "10", and "11" respectively. If the length of a CoAP packet is l 1 and l 2 Between, that is, l 1 <l≤l 2 , then the CoAP data packet is equivalent to carrying two bits of secret information "01".

[0051] The storage method of the covert channel is as follows: In order to increase the capacity of the covert channel, that is, the amount of secret information embedded, the length of the data packet is selected to be in the maximum length interval (i.e., l>l i ) and embed secret information directly in the variable fields of these CoAP packets. The embedding amount is set according to the embedding requirements. Specifically, the number of bits of embedded information b is written into field s 1 , corresponding to the number of bits of secret information embedded in field s 2 , field s 1 For optional Option, field s 2 is an optional payload, and the amount of embedding b each time is no more than field s 1 The maximum value V max A random number, V max It can be understood as field s 1 Theoretically, the maximum number of bits of information that can be written is V max is the theoretical maximum number of embedded information bits. At the same time, the peak value of the embedded amount b cannot exceed the actual maximum number of bits L represented by this field in the original traffic data packet. max, L max It can be understood that in actual use, field s 1 The maximum number of bits of information to be written, i.e. L max is the actual maximum number of embedded information bits. That is, the size range of b is [b min , b max ], where b min The value range is 0≤b min ≤ b max , and b max The value range is b min ≤ b max ≤Min(V max , L max ). When b min and b max When both are set to zero, the amount of data packet field embedded directly is zero, which is equivalent to suspending the covert communication of the storage covert channel at this time, but it does not affect the normal operation of the time covert channel. When the covert channel has a high capacity demand, b min and b max The value of is appropriately increased within its value range.

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

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

[0054] (2) Arrange and combine the k bits of secret information to obtain i+1 combinations.

[0055] (3) Each length interval is set to correspond to a combination, and the corresponding relationship between the length interval of the preset CoAP data packet length and the secret information is obtained.

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

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

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

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

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

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

[0062] (6) If so, all selected data packets are sorted in the order in which they are selected, so as to sort the multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be concealedly transmitted.

[0063] At this time, in S3, based on the correspondence between the preset CoAP data packet length interval and the secret information, multiple CoAP data packets are sorted, specifically including:

[0064] (1) Selecting a preset number of bits of secret information from the secret information to be concealed and transmitted, and selecting the first k bits of secret information of the preset number of bits as the secret information to be embedded.

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

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

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

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

[0069] (6) If so, all selected data packets are sorted in the order in which they are selected, so as to sort the multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute a secret information of a preset number of bits.

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

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

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

[0073] Embedding the first digit of secret information in the variable field of the data packet to be embedded specifically includes: for each data packet to be embedded, according to the number of embedded information bits of the data packet to be embedded, embedding the secret information in the variable field of the data packet to be embedded, and the secret information embedded in all the data packets to be embedded constitutes the first digit of secret information. Wherein, the number of embedded information bits b is in [b min , b max ]A random number in the range 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, L max is the actual maximum number of embedded information bits.

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

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

[0076] In this embodiment, four message types of CoAP data packets are set as P1, P2, P3, and P4, and a combination sequence of n (preferably, n≥4) consecutive CoAP data packets of one message type is selected as a boundary identification sequence. For example, a combination sequence of four consecutive P1 data packets is designated as a start boundary identification of the start of covert communication and an end boundary identification of the end of covert communication. If four consecutive P1 data packets appear in the original traffic data packet, the data packet sequence is adjusted so that data packets of other message types are inserted into the four consecutive P1 data packets to avoid the appearance of a continuous combination sequence that is the same as the boundary identification sequence. When the set start boundary identification consisting of n consecutive CoAP data packets of the same message type appears, the covert communication begins, and when the set end boundary identification consisting of n consecutive CoAP data packets of the same message type appears, the covert communication ends.

[0077] At this time, after making the sorted multiple CoAP data packets form the secret information to be transmitted covertly, the hybrid covert communication method for the Internet of Things of this embodiment further includes: adding a start boundary identifier in front of the sorted multiple CoAP data packets, adding an end boundary identifier after the sorted multiple CoAP data packets to form a data packet to be transmitted, and sending the data packet to be transmitted to the receiving end. Wherein, the start boundary identifier and the end boundary identifier both include n CoAP data packets of the same message type, n is a positive integer greater than 1, and the message types include confirmation-required messages, confirmation-unrequired messages, confirmation response messages, and reset messages.

[0078] In this embodiment, the method for selecting i and b includes: if the communication network environment is complex or there is a security threat, then i and b are reduced; if the amount of secret information embedded is required to be large, then i and b are increased.

[0079] This embodiment can adjust parameters according to the mobile network situation or the embedding amount requirement to achieve the adaptability of security requirements. If the communication network environment is complex or there is a security threat, the i value can be appropriately adjusted to a smaller value and the b value can also be adjusted to a smaller value, which can improve the robustness and anti-detection of the covert channel. This is because the smaller the i value, the more CoAP packets that can be selected for the same secret information, and the stronger the concealment; if the embedding amount of secret information is required to be large, the i value can be appropriately increased and the b value can also be appropriately increased, so that the number of secret information bits carried by each CoAP packet of different lengths will increase, especially the direct embedding amount of secret information in the CoAP packet of the maximum length range will also increase.

[0080] This embodiment provides a hybrid covert communication method based on the Internet of Things communication protocol CoAP. In an Internet of Things environment using the CoAP network protocol, secret information to be covered is covered by using a mixture of a time covert channel and a storage covert channel. The time covert channel method embeds secret information through a combined sequence of CoAP data packets of different lengths, and the storage covert channel method directly embeds secret information into a variable field of CoAP data packets whose lengths are within a certain length range. This method can ensure the robustness, anti-detection and high capacity of covert channels for covert communication, and can adjust parameters according to mobile network conditions or embedding requirements to achieve adaptability to 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 covered and 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 covered and 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] Example 2

[0083] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 3 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to 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 an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a hybrid covert communication method for the Internet of Things is implemented.

[0084] Those skilled in the art will understand that Figure 3The structure shown in the figure is only a block diagram of a part of the structure 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 certain components, or have a different arrangement of components.

[0085] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the hybrid covert communication method for the Internet of Things in Example 1 is implemented.

[0086] Example 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] Example 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 used 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 must comply with relevant regulations.

[0091] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0092] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting 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: Determining whether the number of bits of the secret information to be concealedly transmitted is greater than a preset number of bits; If not, based on the correspondence between the preset CoAP data packet length interval and the secret information, the multiple CoAP data packets are sorted so that the sorted multiple CoAP data packets constitute the secret information to be concealedly transmitted; If so, based on the correspondence between the length interval of the preset CoAP data packet length and the secret information, multiple CoAP data packets are sorted, and the first digit of the secret information is embedded in the sorted multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly; wherein the first digit is equal to the difference between the total number of bits of the secret information to be transmitted covertly and the preset number of bits.

2. The hybrid covert communication method for the Internet of Things according to claim 1 is characterized in that: Before sorting the multiple CoAP data packets based on the correspondence between the preset CoAP data packet length interval and the secret information, the hybrid covert communication method for the Internet of Things further includes: According to the distribution of CoAP packet length, the CoAP packet length is divided into i+1 length intervals; where i=2 k -1, k is a positive integer; Arrange and combine the k bits of secret information to obtain i+1 combinations; Each length interval is set to correspond to a combination, and the corresponding relationship between the length interval of the preset CoAP data packet length and the secret information is obtained.

3. The hybrid covert communication method for the Internet of Things according to claim 1 is characterized in that: Based on the correspondence between the preset CoAP data packet length interval and the secret information, multiple CoAP data packets are sorted so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly, specifically including: Select the first k bits of the secret information to be transmitted covertly as the secret information to be embedded; Determine the length interval corresponding to the secret information to be embedded based on the correspondence between the secret information to be embedded, the preset CoAP data packet length, and the secret information; Selecting a CoAP data packet whose data packet length is within a length interval corresponding to the secret information to be embedded from multiple CoAP data packets as the selected data packet; Determine whether the number of bits of the secret information to be concealedly transmitted in the current iteration is 0; If not, the secret information to be embedded is removed from the secret information to be concealedly transmitted in the current iteration to obtain the secret information to be concealedly transmitted in the next iteration, and the process returns to the step of "selecting the first k bits of the secret information to be concealedly transmitted as the secret information to be embedded"; If so, all selected data packets are sorted in the order in which they are selected, so as to sort the multiple CoAP data packets, so that the sorted multiple CoAP data packets constitute the secret information to be transmitted covertly.

4. The hybrid covert communication method for the Internet of Things according to claim 2 is characterized in that: The secret information of the first digit is embedded in the sorted multiple CoAP packets, including: Among the sorted CoAP data packets, a CoAP data packet with a data packet length in the largest length interval is selected as the data packet to be embedded; The first digit of secret information is embedded in the variable field of the data packet to be embedded.

5. The hybrid covert communication method for the Internet of Things according to claim 4 is characterized in that: Embed the first digit of secret information in the variable field of the data packet to be embedded, including: For each data packet to be embedded, according to the number of embedded information bits 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 the data packets to be embedded constitutes the secret information of the first digit; Among them, the number of embedded information bits b is in [b min , b max ]A random number in the range 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, L max is the actual maximum number of embedded information bits.

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

7. The hybrid covert communication method for the Internet of Things according to claim 1, characterized in that: After the sorted multiple CoAP data packets are made into secret information to be covertly transmitted, the hybrid covert communication method for the Internet of Things further includes: A start boundary identifier is added in front of the sorted multiple CoAP data packets, and an end boundary identifier is added after the sorted multiple CoAP data packets to form a data packet to be transmitted, and the data packet to be transmitted is sent to the receiving end; wherein, the start boundary identifier and the end boundary identifier both include n CoAP data packets of the same message type, n is a positive integer greater than 1, and the message types include confirmation required messages, confirmation not required messages, confirmation response messages and reset messages.

8. The hybrid covert communication method for the Internet of Things according to claim 4, characterized in that: The method for selecting i and b includes: if the communication network environment is complex or there is a security threat, then i and b are reduced; if the amount of secret information embedded is required to be large, then i and b are increased.

9. A computer device comprising: A memory, a processor, and a computer program stored in 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 as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the hybrid covert communication method for the Internet of Things described in any one of claims 1 to 8 is implemented.

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