Mobile Internet of Things equipment group signature method and system based on privacy protection

Abstract

The invention provides a mobile Internet of Things device group signature method and system based on privacy protection, and the method comprises the steps: obtaining a group initialization parameter generated by an issuer, and distributing a group signature key to a target device applying for joining a group based on the group initialization parameter; determining a current event token of the target device on the basis of the group signature key in combination with a preset event definition rule, and judging whether the event of the target vehicle changes or not on the basis of the event token to obtain a judgment result; if the judgment result is yes, signing based on the group signature key and the current event token to obtain a group signature; if the judgment result is no, signing based on the group signature successfully obtained last time and the current event token to obtain an event signature; and performing effective verification on the group signature or the event signature based on the group public key and the current event token to obtain an effective group signature or an effective event signature. According to the invention, the privacy protection requirement of dynamic change in the scene of the mobile Internet of Things is met.

Description

Technical Field

[0001] This invention relates to the field of computer technology, and in particular to a privacy-preserving method and system for group signature of mobile Internet of Things (IoT) devices. Background Technology

[0002] In mobile Internet of Things (IoT) applications, such as fleet formation and road cooperative driving, it is necessary to authenticate the messages sent by devices while protecting device privacy and preventing the leakage of specific identity information. Group signature technology has emerged to meet this need.

[0003] Existing group signature methods for mobile IoT devices typically involve a group management organization generating a unified group key and distributing it to all group members. Group members use this group key to sign messages, and a verifier uses the group public key to verify whether the message originated from a member within the group. However, in existing methods, the use of a unified group key leads to excessive computational overhead during the signing and verification process, especially in scenarios with many group members and frequent message transmissions. This reduces communication efficiency and affects the real-time response performance of mobile IoT devices. Furthermore, the balance between privacy protection and identity traceability is poor. Either effective privacy revocation is difficult to achieve, making it impossible to trace the sender's true identity when necessary, or the privacy protection is insufficient, making it easy for member identity information to be illegally cracked. Moreover, the scope and duration of identity linkability cannot be flexibly controlled, making it difficult to meet the dynamically changing privacy protection needs in mobile IoT scenarios. Summary of the Invention

[0004] This invention provides a privacy-preserving mobile IoT device group signature method and system to solve the problems of high computational overhead, low communication efficiency, and reduced real-time response performance caused by the unified group key in existing methods. It balances the relationship between privacy protection and identity traceability, and achieves the effect of tracing the real identity through privacy revocation when necessary, while strengthening the privacy protection by relying on exclusive keys and dynamic tokens.

[0005] In a first aspect, the present invention provides a privacy-preserving method for group signature of mobile Internet of Things (IoT) devices, comprising: Obtain the group initialization parameters generated by the issuer, and allocate the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key, and the group public key; Based on the group signature key and the preset event definition rules, the current event token of the target device is determined, and the event token is used to determine whether the event of the target vehicle has changed, and the determination result is obtained. If the judgment result is yes, then the group signature is obtained by signing based on the group signature key and the current event token; if the judgment result is no, then the event signature is obtained by signing based on the previously successfully obtained group signature and the current event token. The group signature or event signature is verified based on the group public key and the current event token to obtain a valid group signature or a valid event signature. Privacy revocation is then performed based on the master unlocking key and the registration information of the target device, combined with the valid group signature, to obtain the corresponding traceability result.

[0006] Secondly, the present invention also provides a privacy-preserving mobile IoT device group signature system, applied to the privacy-preserving mobile IoT device group signature method as described in the first aspect; the privacy-preserving mobile IoT device group signature system includes: The key distribution module is used to obtain the group initialization parameters generated by the issuer and distribute the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key and the group public key; The event token generation and change judgment module is used to determine the current event token of the target device based on the group signature key and the preset event definition rules, and to judge whether the event of the target vehicle has changed based on the event token, and obtain the judgment result. The layered signature generation module is used to sign the event signature based on the group signature key and the current event token if the judgment result is yes; if the judgment result is no, it is used to sign the event signature based on the previously successfully obtained group signature and the current event token. The valid verification and privacy revocation module is used to verify the group signature or event signature based on the group public key and the current event token to obtain a valid group signature or valid event signature, and to revoke privacy based on the master unlocking key and the registration information of the target device combined with the valid group signature to obtain the corresponding traceability result.

[0007] Thirdly, the present invention also provides an electronic device, comprising: a memory for storing computer software programs; and a processor for reading and executing the computer software programs, thereby implementing the privacy-preserving mobile Internet of Things device group signature method as described above.

[0008] Fourthly, the present invention also provides a non-transitory computer-readable storage medium storing a computer software program, which, when executed by a processor, implements the privacy-preserving mobile Internet of Things device group signature method as described above.

[0009] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the privacy-preserving mobile Internet of Things device group signature method as described above.

[0010] The privacy-preserving mobile IoT device group signature method provided in this invention obtains a unique group signature key bound to the group initialization parameters by acquiring the group initialization parameters generated by the issuer and allocating a group signature key. Based on this group signature key and preset event definition rules, the current event token suitable for the target vehicle is determined, thereby judging whether the event has changed and obtaining an accurate event change judgment result. Then, based on this judgment result, a flexible signature method is selected: when the event has changed, the current group signature key and the current event token are used for signing; when the event has not changed, the previous group signature key and the current event token are used for signing. This eliminates the need for repeated signature calculations using a unified group key each time, effectively reducing the computational overhead in the signature process. Finally, the method... The signature is effectively verified using the group public key and the current event token, ensuring its validity while controlling the computational complexity of the verification phase. By combining the master unlocking key, target device registration information, and signature, privacy revocation is performed and traceability results are obtained. This solves the problems of high computational overhead, low communication efficiency, and impact on real-time response performance caused by the unified group key in existing methods. It also balances the relationship between privacy protection and identity traceability, achieving the effect of tracing the real identity through privacy revocation when necessary, while strengthening privacy protection by relying on exclusive keys and dynamic tokens. Furthermore, the dynamic adjustment of the signature method through the event token flexibly controls the scope and duration of identity linkability, meeting the dynamically changing privacy protection needs in mobile IoT scenarios. Attached Figure Description

[0011] Figure 1 This is a flowchart illustrating the privacy-preserving mobile IoT device group signature method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a privacy-preserving mobile IoT device group signature system provided in an embodiment of the present invention; Figure 3 An embodiment diagram of the electronic device provided in this invention; Figure 4 An embodiment diagram of a computer-readable storage medium provided in accordance with the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0014] In the description of this invention, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this invention is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.

[0015] See Figure 1 , Figure 1 This is a flowchart illustrating the privacy-preserving mobile IoT device group signature method provided by the present invention. In this embodiment, the executing entity of the privacy-preserving mobile IoT device group signature method is a group signature system. Therefore, the privacy-preserving mobile IoT device group signature method includes: Step 10: Obtain the group initialization parameters generated by the issuer, and allocate a group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key, and the group public key.

[0016] Optionally, at the initial stage, the group signature system performs a group initialization operation by the built-in issuer, generating three sets of group initialization parameters with specific functions, including a master issuing key, a master unlocking key, and a group public key. The master issuing key is a core key specifically used by the issuer to generate group signature keys for devices applying to join the group. It is held exclusively by the issuer and is used to ensure the security and uniqueness of the group signature key allocation. The master unlocking key is a key for subsequent privacy revocation and tracing the sender's true identity. It is also held exclusively by the issuer and is used to unlock the real identity information corresponding to the group signature when necessary. The group public key is a public verification key that can be obtained and used by all verifiers who need to verify message signatures to confirm whether the message signature comes from a member within the group.

[0017] After the issuer generates the group initialization parameters, the target device, as a user wishing to join the group, submits a request to the group signature system. This request includes the target device's valid identification information, which the issuer uses to verify the target device's eligibility to join. Upon receiving the request, the group signature system forwards it to the issuer, which then verifies the validity of the target device's identification information. This verification includes confirming whether the target device is a mobile IoT device that meets the group's access criteria and whether the identification information is authentic and valid.

[0018] If the target device passes the legitimacy verification, the issuer will generate a unique group signature key for the target device based on the generated master issuance key and group public key, combined with the target device's identity information. The group signature key is the exclusive key used by the target device for subsequent message signing; each target device's group signature key is unique to ensure signature uniqueness and traceability. After generating the group signature key, the issuer sends it to the target device through a secure communication channel. Simultaneously, it stores the target device's identity information and group signature key allocation records as registration information for future privacy revocation. Upon receiving the group signature key, the target device verifies its validity using a preset verification algorithm. If verification is successful, the group joining process is complete, and the target device becomes a legitimate member of the group.

[0019] In one embodiment, in a mobile IoT application scenario involving a fleet of convoys, a logistics company plans to establish a fleet of 20 freight vehicles. Each freight vehicle's onboard unit serves as the target device and needs to be added to the corresponding mobile IoT device group for the fleet. First, the issuer of the group signature system generates three sets of group initialization parameters: a master issuing key, a master unlocking key, and a group public key. The group public key is then publicly disclosed to the logistics company's logistics management platform for subsequent use by the platform's verification module.

[0020] The on-vehicle unit of each freight vehicle sends an application request to join the group to the group signature system. The application request contains legal identity identification information such as the license plate number and vehicle identification number of the freight vehicle corresponding to the on-vehicle unit. The group signature system forwards these application requests to the issuer. The issuer verifies the legality of the license plate number and vehicle identification number of each freight vehicle, and confirms that these vehicles are all freight vehicles that have been registered and filed under the name of this logistics enterprise, and the identity identification information is true and valid.

[0021] After the verification is passed, the issuer generates a unique group signature key for the on-vehicle unit of each freight vehicle based on the master issuance key and the group public key. For example, it generates group signature key 1 for the on-vehicle unit corresponding to the freight vehicle with the license plate number Jing A12345, and generates group signature key 2 for the on-vehicle unit corresponding to the freight vehicle with the license plate number Jing A12346, and so on, to ensure that the on-vehicle units of 20 freight vehicles each hold an exclusive group signature key. The issuer sends the generated group signature key to the corresponding on-vehicle unit through an encrypted wireless communication channel, and at the same time stores the license plate number, vehicle identification number, corresponding group signature key allocation record, etc. of each vehicle as registration information in the issuer's database. After each on-vehicle unit receives the group signature key, it verifies the validity of the group signature key through the built-in verification program. After the verification is passed, it successfully joins the group of mobile Internet of Things devices.

[0022] Step 20: Based on the group signature key and the preset event definition rules, determine the current event token of the target device, and judge whether the event of the target vehicle has changed based on the event token, and obtain the judgment result.

[0023] Optionally, the group signature system obtains the group signature key and synchronously retrieves the preset event definition rules. The event definition rules refer to the rules jointly recognized and followed by all group members, which are used to clarify the type of events and the generation method of event tokens, and are pre-stored in the group signature system. The types of events include location-related types and time-related types. The location-related types of events refer to events divided based on a specific geographical range, such as a specific highway section with a length of 5 kilometers, a city road intersection, etc., which are clear geographical areas; the time-related types of events refer to events divided based on a fixed time interval, such as every 10 minutes, every 30 minutes, etc., which are fixed durations. Based on this, the current event token of the target device is generated, specifically as the process from step 201 to step 204.

[0024] Optionally, after generating the current event token for the target device at the current moment, the group signature system retrieves the historical event token used when the target device last signed a message, compares the current event token with the historical event token, and determines whether they are consistent. If they are inconsistent, it is determined that the event of the target device has changed, and the judgment result is yes; if they are consistent, it is determined that the event of the target device has not changed, and the judgment result is no.

[0025] Step 30: If the judgment result is yes, then sign based on the group signature key and the current event token to obtain the group signature; if the judgment result is no, then sign based on the previously successfully obtained group signature and the current event token to obtain the event signature.

[0026] Optionally, after obtaining the judgment result, the group signature system performs corresponding signature processing based on the different judgment results. That is, when the judgment result is yes, the event of the target device has changed. The group signature system calls the group signature key held by the target device and extracts the current event token generated in step 20. The group signature key and the current event token are used as the core input information for signature generation. The system performs calculations according to the preset group signature generation logic to generate the corresponding group signature. This group signature can identify that the message comes from a member within the group and includes core content such as the event status change identifier, signature time, and target device group affiliation information. When the judgment result is no, it indicates that the event of the target device has not changed. At this time, the group signature system retrieves the group signature and current event token that were successfully generated and stored on the target device last time, and generates an event signature based on these, as described in steps 301 to 303.

[0027] Step 40: Verify the group signature or event signature based on the group public key and the current event token to obtain a valid group signature or valid event signature. Then, perform privacy revocation based on the master unlocking key and the registration information of the target device combined with the valid group signature to obtain the corresponding traceability result.

[0028] Optionally, after receiving a message with a group signature or event signature from the target device, the group signature system extracts the group signature or event signature attached to the message. Simultaneously, it obtains the group formula and the generated current event token from the group initialization parameters. The system then uses the group public key and the current event token to verify the group signature or event signature, determining whether it conforms to the generation rules, is consistent with the current event state, and originates from a legitimate group member device. If the verification passes, the group signature or event signature is confirmed as a valid signature, resulting in a valid group signature or a valid event signature, as detailed in steps 401 to 404. Simultaneously, the message received by the group signature system is considered a valid message, and it is confirmed that the message originates from a member within the group. If the verification fails, the group signature or event signature is determined to be an invalid signature, and the corresponding message is not trusted. The group signature system may refuse to process the message or send a verification failure message to the sending device.

[0029] Furthermore, when privacy revocation is required, the group signature system obtains the master unlocking key held by the issuer, retrieves the registration information of the target device stored in step 10, associates the master unlocking key, the registration information of the target device with the valid group signature, performs the operation according to the preset privacy revocation logic, clarifies the true identity information of the target device corresponding to the valid group signature, and obtains the corresponding traceability result, as detailed in steps 405 to 408.

[0030] This invention obtains a unique group signature key bound to the group initialization parameters by acquiring the group initialization parameters generated by the issuer and allocating a group signature key. Based on this group signature key and preset event definition rules, the current event token suitable for the target vehicle is determined, thereby judging whether the event has changed and obtaining an accurate event change judgment result. Based on this judgment result, a flexible signature method is selected: when the event has changed, the current group signature key and the current event token are used for signing; when the event has not changed, the previous group signature key and the current event token are used for signing. This eliminates the need to repeatedly use the same group key for signing each time, effectively reducing the computational overhead in the signing process. Finally, the group public key and the current event token are used to... The signature is effectively verified, ensuring its validity while controlling the computational complexity of the verification phase. By combining the master unlocking key, target device registration information, and signature, privacy revocation is performed and traceability results are obtained. This solves the problems of high computational overhead, low communication efficiency, and impact on real-time response performance caused by the unified group key in existing methods. It also balances the relationship between privacy protection and identity traceability, achieving the effect of tracing the real identity through privacy revocation when necessary, while strengthening privacy protection by relying on exclusive keys and dynamic tokens. Furthermore, the dynamic adjustment of the signature method through event tokens flexibly controls the scope and duration of identity linkability, meeting the dynamically changing privacy protection needs in mobile IoT scenarios.

[0031] Optionally, the processes of steps 201 to 204 include: Step 201: Cryptographically bind the group signature key and the device identity of the target device to obtain the context parameters of the device-specific event.

[0032] Optionally, the group signature system uses the group signature key allocated to the target device in step 10 and the device identity identifier of the target device obtained synchronously. The device identity identifier is information used to uniquely distinguish the target device, including but not limited to device number, hardware serial number, and legal identity information submitted during registration, ensuring the uniqueness of the identity identifier of each group member device. A preset cryptographic binding algorithm is used to associate and integrate the group signature key and the device identity identifier. This cryptographic binding algorithm is designed based on cryptographic principles such as symmetric encryption, asymmetric encryption, or hash functions. Its purpose is to establish an inseparable binding relationship between the group signature key and the device identity identifier, preventing them from being tampered with or illegally replaced. After processing by this algorithm, context parameters for a device-specific event are generated. These context parameters contain intermediate data of the binding information between the group signature key and the device identity identifier, and these context parameters correspond only to the current target device.

[0033] In one embodiment, in a convoy application scenario, the onboard unit (target device) of a freight vehicle has obtained the group signature key (the key content is an encrypted string of characters) allocated in step 10, and its device identification is the hardware serial number "1234567890123456" of the onboard unit. The group signature system uses a hash function-based cryptographic binding algorithm to associate and integrate the above-mentioned group signature key with the hardware serial number "1234567890123456". By performing hash calculation on the combined data of the two, a context parameter "hash value combination string D" for the device-specific event is generated. This context parameter uniquely corresponds to the onboard unit of this freight vehicle and contains the binding information of the device's group signature key and identification.

[0034] Step 202: Match the event type based on the context parameters and the event type in the event definition rules to obtain the current event type.

[0035] Optionally, the group signature system, based on the obtained context parameters and retrieving the event types from the event definition rules, performs correlation matching between the context parameters and the two event types in the event definition rules according to the preset matching logic in the event definition rules. That is, based on the event type classification criteria, it extracts the target device status association information implicit in the context parameters and determines which event type characteristics this information better matches. If the target device status information associated in the context parameters is related to geographical location, it matches as a location-related type; if it is related to time period, it matches as a time-related type, ultimately obtaining the current event type.

[0036] Continuing with the above embodiments, in the road cooperative driving application scenario, the event types in the preset event definition rules of the group signature system include location-related types (based on a 3-kilometer-long urban expressway segment) and time-related types (based on 15-minute intervals). The context parameter "hash value combination string E" generated in sub-step 201 of a target device (a small car's onboard unit) implicitly contains the real-time geographical location association information of the onboard unit. The group signature system, according to preset matching logic, extracts the geographical location association features from this context parameter and matches them with the two event types in the event definition rules. It finds that the feature matches the location-related type, thus determining the current event type to be location-related.

[0037] Step 203: Perform structured encapsulation based on the current event type and context parameters to obtain the event semantic structure; the event semantic structure includes the event type identifier, device identity context information, and event occurrence logic context.

[0038] Optionally, the group signature system, based on the current event type and context parameters, first extracts the device identity context information from the context parameters. This device identity context information is core data related to the target device's identity contained in the context parameters, clearly reflecting the target device's identity association attributes. Simultaneously, combining the characteristics of the current event type, an event occurrence logical context is generated. This event occurrence logical context refers to information describing the logical basis and judgment criteria for the occurrence and changes of the event under the current event type. For example, the event occurrence logical context for location-related types includes geographical boundaries and location judgment rules, while the event occurrence logical context for time-related types includes time intervals and time node judgment rules. Finally, according to a preset structured encapsulation format, the event type identifier, device identity context information, and event occurrence logical context are integrated and encapsulated to form an event semantic structure. The structured encapsulation format is a pre-defined fixed data organization form that ensures that various types of information within the event semantic structure are arranged in an orderly manner and clearly distinguished.

[0039] Continuing with the above embodiment, in the vehicle fleet formation application scenario, the current event type of a target device (the on-vehicle unit of a freight vehicle) is a time-related type (with an event cycle of every 10 minutes), and the corresponding event type identifier is "02". The group signature system extracts the device identity context information from the context parameter "hash value combination string F", and this information is "freight vehicle license plate number Jing A98765 - group signature key binding digest"; combining the characteristics of the time-related type, the event occurrence logic context is generated as "the event cycle is 10 minutes, starting from 0 minutes at the whole hour, and it is determined that the event has changed every time 10 minutes have elapsed cumulatively". According to the preset structured encapsulation format, the event type identifier "02", the device identity context information "freight vehicle license plate number Jing A98765 - group signature key binding digest", and the event occurrence logic context "the event cycle is 10 minutes, starting from 0 minutes at the whole hour, and it is determined that the event has changed every time 10 minutes have elapsed cumulatively" are integrated and encapsulated to obtain the event semantic structure "[event type identifier: 02; device identity context information: freight vehicle license plate number Jing A98765 - group signature key binding digest; event occurrence logic context: the event cycle is 10 minutes, starting from 0 minutes at the whole hour, and it is determined that the event has changed every time 10 minutes have elapsed cumulatively]".

[0040] Step 204, perform hash binding based on the event semantic structure and the group signature key to obtain the current event token of the target device.

[0041] Optionally, the group signature system uses a preset hash algorithm (such as the SHA-256 hash algorithm) according to the event semantic structure and the group signature key retrieved synchronously, and performs hash binding processing on the event semantic structure and the group signature key. That is, through this hash algorithm, the event semantic structure and the group signature key are integrated and calculated to generate data in the form of a fixed-length string, and this data is the current event token of the target device, which is used for subsequent event change judgment, signature generation, and signature verification processes.

[0042] Continuing with the above embodiment, in the road collaborative driving application scenario, the event semantic structure of a target device (the on-vehicle unit of a small car) is "[event type identifier: 01; device identity context information: small car license plate number Hu B12345 - group signature key binding digest; event occurrence logic context: the urban intersection area with a geographical range of 121.47 degrees - 121.49 degrees east longitude and 31.23 degrees - 31.25 degrees north latitude, and entering this area is determined as the current event]", and its group signature key is the exclusive key "encrypted character combination G" allocated in step 10. The group signature system uses the SHA-256 hash algorithm to perform an integrated calculation on the above event semantic structure and the group signature key "encrypted character combination G" to generate a 64-bit fixed-length string "hash result combination string H", and this string is the current event token of the target device.

[0043] The event token generated in this embodiment of the invention is both exclusively bound to the target device and dynamically associated with the current event state, making subsequent event change judgments based on the event token more accurate and reliable.

[0044] Optionally, the processes of steps 301 to 303 include: Step 301: Based on the previously successfully obtained group signature and the current event token, perform standardized cryptographic concatenation and binding to obtain the signature binding input.

[0045] Optionally, the group signature system retrieves the previously successfully obtained group signature. This group signature is a valid signature generated by the target device based on the group signature key and the corresponding event token when an event changes. It identifies that the message comes from a member within the group and is associated with a specific event state. Simultaneously, it retrieves the current event token and integrates the group signature and the current event token using a predefined, standardized cryptographic concatenation and binding rule. This standardized cryptographic concatenation and binding rule refers to a predefined concatenation logic with consistency and security. Its purpose is to ensure that the concatenation order of the group signature and the current event token is fixed, that data is not tampered with or lost during the concatenation process, and that the concatenation result is verifiable. After binding the group signature and the current event token using this rule, a signature binding input is generated. This signature binding input is intermediate data that integrates historical valid group signatures and current event state information.

[0046] In one embodiment, in a convoy application scenario, the group signature successfully obtained by the onboard unit (target device) of a freight vehicle in the previous instance is "Group Signature Data String 1" (this data string is a valid signature generated based on the group signature key and the previous event token), and the current event token is "Event Token Data String 2" (an encrypted string corresponding to the currently traveled 3-kilometer road segment). The group signature system concatenates "Group Signature Data String 1" and "Event Token Data String 2" sequentially according to the preset standardized cryptographic concatenation and binding rule of "group signature first, current event token second," and ensures that the boundary between the two is clear by adding a fixed-length separator (the separator is "###"), finally obtaining the signature binding input "Group Signature Data String 1###Event Token Data String 2".

[0047] Step 302: Perform encrypted signature processing based on the signature binding input and the group signature key to obtain the original signature.

[0048] Optionally, the group signature system uses a preset encryption signature algorithm (such as elliptic curve cryptography) to perform encryption operations on the signature binding input and the group signature key based on the signature binding input and the group signature key. During the encryption process, the group signature key serves as the core encryption key, ensuring that only the target device holding this exclusive key can generate a valid encryption result, and other devices cannot generate the same encrypted data through illegal means. After processing by this encryption signature algorithm, the original signature is obtained. This original signature is the encrypted core signature data, containing the encrypted information of the signature binding input and the verification association information of the group signature key.

[0049] Continuing with the above embodiments, in a road cooperative driving application scenario, the signature binding input generated by a small car's on-board unit (target device) is "group signature data string 3### event token data string 4", and the assigned group signature key is "dedicated key string 5" (this key is the unique encryption key of the on-board unit). The group signature system uses an elliptic curve cryptography algorithm (an asymmetric encryption signature algorithm), taking "group signature data string 3### event token data string 4" as the encrypted input data and "dedicated key string 5" as the encryption key, and performing encryption operations. After performing a series of operations such as elliptic curve point operations and hash operations on the input data, the original signature "original encrypted signature string 6" is generated.

[0050] Step 303: Perform structured encapsulation and encoding based on the original signature and the current event token to obtain the event signature.

[0051] Optionally, the group signature system integrates and encapsulates the original signature and the current event token based on a preset structured encapsulation format. The structured encapsulation format is a predefined, fixed data organization form used to clarify the order of the original signature and the current event token in the encapsulation result, field identifiers, data length, and other requirements, ensuring a clear data structure after encapsulation. After structured encapsulation, the group signature system uses a preset encoding algorithm (such as Base64 encoding) to encode the encapsulated data. Through structured encapsulation and encoding, the event signature is finally obtained.

[0052] Continuing with the above embodiments, in a convoy application scenario, the original signature generated by the onboard unit (target device) of a freight vehicle is "original encrypted signature string 7", and the current event token is "event token data string 8". The group signature system, according to a preset structured encapsulation format, identifies the original signature field as "original signature" and the current event token field as "event token", and integrates and encapsulates them to obtain "{original signature: original encrypted signature string 7; event token: event token data string 8}". Subsequently, the encapsulated data is encoded using the Base64 encoding algorithm, converting it into a transmittable string format, ultimately obtaining the event signature "encoded string 9" (this string is standardized data after Base64 encoding).

[0053] This invention first performs standardized cryptographic concatenation and binding of historical valid group signatures with the current event token, ensuring a strong correlation and data integrity between the event signature and historical signature states and the current event state. Then, it combines this with the target device's dedicated group signature key for encrypted signing, guaranteeing the security and uniqueness of the event signature and preventing illegal forgery or tampering. Finally, it forms a standardized event signature through structured encapsulation and encoding, ensuring the transmissibility and verifiability of the signature data, reducing the computational overhead of the signing process, and strengthening privacy protection through binding with the event token and the encrypted protection of the dedicated group signature key.

[0054] Optionally, the processes of steps 401 to 404 include: Step 401: Based on the current event token and the received signature to be verified, parse the signature header field and extract the type identifier to obtain the signature type.

[0055] Optionally, the group signature system, based on the current event token and the received signature to be verified, where the signature to be verified is a group signature or event signature generated by the target device in step 30, parses the signature header field of the signature to be verified. The signature header field is a pre-defined field area in the signature to be verified used to identify the basic signature information, and its position, length, and data format are all based on preset standardized specifications. During the parsing process, the type identifier in the signature header field is extracted. The type identifier refers to exclusive identification information used to clearly distinguish whether the signature to be verified is a group signature or an event signature. For example, "001" represents a group signature, and "002" represents an event signature. This identifier has been embedded in the signature header field according to unified rules during the signature generation stage. By parsing the signature header field and extracting the type identifier, the specific type of the signature to be verified is determined, and the signature type is obtained.

[0056] In one embodiment, in a road cooperative driving scenario, a message sent by a small car's onboard unit (target device) contains a signature to be verified, "signature data string 10," and the current event token is "event token data string 11" (an encrypted string corresponding to the currently driving urban intersection area). After receiving the message, the group signature system extracts "signature data string 10" as the signature to be verified and parses the header field of the signature according to a preset standardized specification. This header field is located in the first 10 bits of the signature data, with bits 5 to 7 being the type identifier area. After parsing, the identifier for bits 5 to 7 is "001." According to a preset rule, "001" corresponds to the group signature type, therefore the signature type is a group signature. If the parsed type identifier is "002," then the signature type is an event signature.

[0057] Step 402: If the signature type is a group signature, then the group signature validity is verified based on the group public key and the current event token to obtain the first verification result.

[0058] Optionally, when the group signature system receives a signature of type "group signature," it performs integrated verification of the group signature, group public key, and current event token based on the group public key and the current event token. The verification process includes: verifying whether the group signature was generated by the group signature key of a legitimate member within the group, i.e., decrypting the group signature using the group public key and determining whether the decryption result conforms to a preset format to confirm the legitimacy of the signature's source; and verifying the correlation between the group signature and the current event token, determining whether the event-related information embedded in the group signature is consistent with the current event token to confirm the validity of the event state corresponding to the signature. After verification, a first verification result is obtained. The first verification result is a binary judgment result, i.e., verification passed or verification failed. Verification passed indicates that the group signature's source is legitimate and matches the current event state; verification failed indicates that the group signature has problems such as an illegal source, data tampering, or mismatch with the current event token.

[0059] Continuing with the above embodiments, in the convoy application scenario, the signature to be verified, "Signature Data String 12," is a group signature. The group public key is "Public Verification Key String 13," and the current event token is "Event Token Data String 14." The group signature system uses the RSA public key verification algorithm, taking "Signature Data String 12" as the data to be verified, "Public Verification Key String 13" as the verification key, and "Event Token Data String 14" as the associated verification data, to perform a legality verification operation. Upon verification, if the result obtained by decrypting the group signature using the group public key conforms to the preset format, and the event information embedded in the group signature is completely consistent with "Event Token Data String 14," then the first verification result is successful. If the decryption result does not conform to the preset format, or the event information does not match, then the first verification result is unsuccessful.

[0060] Step 403: If the signature type is an event signature, then a dual verification of binding and legality is performed based on the group public key, the current event token, and the previously successfully obtained group signature to obtain a second verification result.

[0061] Optionally, when the group signature system receives an event signature, it performs a dual verification operation on binding and legitimacy based on the group public key, the current event token, and the previously successfully obtained group signature. Binding verification uses a preset binding verification algorithm (such as a hash association algorithm) to verify the association between the event signature and the previously successfully obtained group signature and the current event token, determining whether the event signature was generated based on the group signature and the current event token. This ensures the continuity and consistency of the event signature with historical signatures and the current event state, preventing unrelated illegal event signatures. Legitimacy verification uses a preset legitimacy verification algorithm (such as an elliptic curve public key verification algorithm) to decrypt and verify the event signature using the group public key, determining whether the event signature was generated by the group signature key of a legitimate member within the group. This ensures the legitimacy of the event signature's source and prevents unauthorized devices from forging the event signature. If both verifications pass, the second verification result is considered successful; if either verification fails, such as an invalid binding relationship or an illegal source, the second verification result is considered unsuccessful.

[0062] Continuing with the above embodiments, in the road cooperative driving application scenario, the signature to be verified, "Signature Data String 15," is an event signature. The group public key is "Public Verification Key String 16," the current event token is "Event Token Data String 17," and the previously successfully obtained group signature is "Group Signature Data String 18." The group signature system first verifies the association between "Signature Data String 15," "Group Signature Data String 18," and "Event Token Data String 17" using a hash association algorithm, confirming that the event signature is generated based on the group signature and the event token. Then, it uses an elliptic curve public key verification algorithm to decrypt and verify "Signature Data String 15" using "Public Verification Key String 16," confirming its legitimate origin. After double verification, if both verifications pass, the second verification result is considered successful. If the hash association algorithm verifies that the association is invalid, or the elliptic curve public key verification algorithm verifies that the origin is illegal, the second verification result is considered a failure.

[0063] Step 404: Based on the first verification result or the second verification result, perform valid signature marking and state encapsulation to obtain a valid group signature or a valid event signature.

[0064] Optionally, the group signature system performs a valid signature marking operation based on the first or second verification result. If the verification result is successful, the corresponding signature to be verified is marked as valid. The valid signature mark is a special mark used to clearly identify the legality and validity of the signature. For example, a valid identifier field is added to the end of the signature data. This mark facilitates the subsequent system to quickly identify the legal signature. If the verification result is unsuccessful, the signature to be verified is not marked as valid, and the reason for failure can be recorded (such as illegal source, invalid binding relationship, etc.).

[0065] Furthermore, after the group signature system completes the valid signature marking, it encapsulates the group signature or event signature with the valid signature marking according to a preset state encapsulation format. The state encapsulation format is a pre-defined standardized data organization form, containing fields such as the original signature data, valid mark information, verification time, and current event token association information, ensuring that the encapsulated signature data structure is complete and the information is comprehensive. Through valid signature marking and state encapsulation, a valid group signature (corresponding to the group signature type and verified) or a valid event signature (corresponding to the event signature type and verified) is finally obtained.

[0066] Continuing with the above embodiments, in the convoy application scenario, the first verification result is "verification passed", and the corresponding group signature to be verified is "signature data string 19"; or the second verification result is "verification passed", and the corresponding event signature to be verified is "signature data string 20". If it is a group signature, the group signature system adds a "valid" identifier field to the end of "signature data string 19" to obtain "signature data string 19 + valid", and then integrates the original signature data, "valid" marker information, verification time (e.g., 14:30:25 on October 1, 2024), and current event token "event token data string 21" according to the preset state encapsulation format to encapsulate and obtain a valid group signature as: {signature data: signature data string 19; marker status: valid; verification time: 14:30:25 on October 1, 2024; associated event token: event token data string 21}. If it is an event signature, the same marking and encapsulation operation is performed on "signature data string 20" to obtain a valid event signature.

[0067] This invention first extracts the type identifier from the header field of the signature to be verified, thus accurately distinguishing between group signatures and event signatures. Then, it performs legality verification or dual verification of binding and legality for different signature types. Combining the group public key, the current event token, and historical valid group signatures, a multi-layered and comprehensive verification system is constructed to ensure the accuracy and security of signature verification. Finally, a standardized valid signature is formed through valid signature marking and state encapsulation, ensuring the standardization of subsequent data processing.

[0068] Optionally, steps 405 to 408 include: Step 405: Perform group signature decryption mapping based on the valid group signature and the master unlocking key to obtain the device anonymous identifier.

[0069] Optionally, the group signature system decrypts the valid group signature using the master unlocking key, strips off the encryption protection layer in the signature, extracts the device association identification information hidden within, and then anonymizes the identification information to obtain the device anonymous identifier. The device anonymous identifier is a unique encrypted string that corresponds to the target device and is used to associate the target device's registration information. This avoids premature disclosure of the real identity during the privacy revocation process, thus ensuring privacy and security.

[0070] In one embodiment, in a convoy application scenario, the valid group signature is "valid group signature data string 22", and the master unlocking key is "dedicated unlocking key string 23". The group signature system adopts a decryption mapping algorithm based on the RSA asymmetric encryption and decryption principle. It uses "valid group signature data string 22" as decryption input data and "dedicated unlocking key string 23" as decryption key to perform decryption operations. By performing layered decryption and information extraction on the encrypted data of the valid group signature, the device anonymous identifier "anonymous identifier string 24" (this string is a unique associated identifier after anonymization processing) is finally obtained.

[0071] Step 406: Based on the device's anonymous identifier and the target device's registration information, a matching query is performed using a pre-built registration information database to obtain the target device's true identity information.

[0072] Optionally, the group signature system is based on the device's anonymous identifier and the target device's registration information, where the target device's registration information is obtained in step 10. This is combined with a pre-built registration information database, which is a structured database specifically used to store the registration information of all group members' devices. Each piece of registration information in the database has a unique mapping relationship with the corresponding device's anonymous identifier, meaning that one device's anonymous identifier corresponds to only one piece of registration information. The system compares the device's anonymous identifier with all the mapping relationships in the registration information database one by one. Through matching queries, the system extracts the corresponding target device's registration information from the registration information database. The information in the registration information that can clearly identify the device's specific identity is the target device's real identity information.

[0073] Continuing with the above embodiment, in the road collaborative driving application scenario, the device anonymous identifier is "anonymous identifier string 25", and the pre-constructed registration information database stores the registration information of each group member device and the corresponding mapping relationship between the device anonymous identifier. The group signature system uses an index matching query algorithm, takes "anonymous identifier string 25" as the query keyword, and retrieves and compares it in the registration information database to quickly locate the corresponding registration information entry. The registration information contained in this entry is "device number: 20240501; hardware serial number: 9876543210987654; license plate number: Yue C67890; vehicle identification number: LVXDG123456789012", where the license plate number: Yue C67890; vehicle identification number: LVXDG123456789012 are the true identity information of the target device.

[0074] Step 407, perform structured encapsulation based on the valid group signature, device anonymous identifier, and true identity information to obtain the identity attribution proof.

[0075] Optionally, the group signature system integrates and encapsulates the above three types of information according to a preset structured encapsulation format. The structured encapsulation format is a pre-defined standardized data organization form, which clarifies the field names, arrangement order, data length, and format requirements of the valid group signature, device anonymous identifier, and true identity information in the encapsulation result. During the encapsulation process, field annotation and format standardization processing are performed on various types of information. After structured encapsulation, an identity attribution proof is generated, where the identity attribution proof is a standardized file that can clarify the attribution relationship between the valid group signature and the true identity of the target device.

[0076] Continuing with the above embodiment, in the vehicle fleet formation application scenario, the valid group signature is "valid group signature data string 26", the device anonymous identifier is "anonymous identifier string 27", and the true identity information is "license plate number: Zhe A13579; vehicle identification number: LSGJA52H3XH123456". The group signature system integrates and encapsulates the three types of information according to a preset structured encapsulation format, and the field annotations are "valid group signature", "device anonymous identifier", and "true identity information" respectively. Finally, the identity attribution proof "{valid group signature: valid group signature data string 26; device anonymous identifier: anonymous identifier string 27; true identity information: license plate number: Zhe A13579, vehicle identification number: LSGJA52H3XH123456}" is obtained.

[0077] Step 408: Verify the decision based on the identity ownership certificate and the group public key to obtain the decision result. If the decision result is true, encapsulate the traceability result and supplement the event context to obtain the traceability result containing the real identity information. If the decision result is false, generate a traceability failure prompt directly.

[0078] Optionally, the group signature system integrates and verifies the proof of ownership and the group public key. Specifically, it uses the group public key to perform secondary verification on the valid group signature in the proof of ownership, confirming that the valid group signature was indeed generated by the group signature key of the target device corresponding to the real identity information. Simultaneously, it verifies the legality and validity of the mapping relationship between the device's anonymous identifier and the real identity information, ensuring that the proof of ownership has not been tampered with or forged. After verification, a decision result is obtained, which is a binary decision result: either the decision is true or the decision is false.

[0079] Furthermore, when the group signature system receives a true ruling, it indicates that the identity attribution proof is authentic and valid, and the attribution relationship between the valid group signature and the target device's authentic identity information is clear. The group signature system encapsulates the tracing results of the authentic identity information, that is, it organizes the authentic identity information in a structured manner according to a preset standardized format to form clear and standardized core tracing content; at the same time, it supplements the event context information corresponding to the valid group signature. The event context information includes relevant information such as the current event token generated in step 20, the event type, the event occurrence time, and the event occurrence location. Finally, through the tracing result encapsulation and event context supplementation, a complete tracing result containing authentic identity information and event context information is obtained.

[0080] If the ruling is false, it indicates that the proof of identity has been tampered with, forged, or the ownership relationship is invalid, making it impossible to clearly identify the true identity information corresponding to the valid group signature. The group signature system directly generates a traceability failure message. This message is a standardized message used to inform the relevant authorized party that the privacy revocation operation was unsuccessful, including an explanation of the reason for the failure (such as invalid proof of identity, invalid mapping relationship, etc.).

[0081] Continuing with the above embodiments, in the road cooperative driving application scenario, the identity ownership proof is {valid group signature: valid group signature data string 28; device anonymous identifier: anonymous identifier string 29; real identity information: license plate number: SuE24680; vehicle identification code: LBVPS310XKM012345}, and the group public key is the public verification key string 30.

[0082] The group signature system uses an elliptic curve public key adjudication verification algorithm to integrate and verify the identity ownership proof and the public verification key string 30. It confirms that the valid group signature is generated by the group signature key of the vehicle unit corresponding to the real identity information, and that the mapping relationship between the device anonymous identifier and the real identity information is legal and valid, thus obtaining a true adjudication result. Subsequently, the supplementary event context information is as follows: Current event token: event token data string 31; Event type: location-related type (urban expressway section between 119.95°E and 31.78°N); Event occurrence time: 09:15:30 on October 2, 2024. After being encapsulated in a standardized format, the traceability result is as follows: {Real identity information: License plate number: Su E24680, Vehicle identification number: LBVPS310XKM012345; Event context information: Current event token: event token data string 31, Event type: location-related type (urban expressway section between 119.95°E and 31.78°N); Event occurrence time: 09:15:30 on October 2, 2024}.

[0083] If the ruling verification finds that the valid group signature and the real identity information have no legitimate ownership relationship, the ruling result is false, and a traceability failure message is generated: traceability failure: the identity ownership proof is invalid, and the mapping relationship between the valid group signature and the real identity information is not established.

[0084] This invention uses a master unlocking key to decrypt and map a valid group signature to obtain an anonymous device identifier, ensuring the authority of the privacy revocation process while preventing premature leakage of real identity information. Then, by matching the anonymous device identifier with the registration information database, the true identity information of the target device is accurately located, achieving accurate identity tracing. Subsequently, a structured encapsulation is used to form an identity ownership proof, constructing a complete chain of ownership evidence. Finally, the group public key is used for adjudication verification, ensuring the legality and reliability of the tracing result. If the adjudication passes, a complete tracing result containing real identity information and event context is generated; if it fails, a clear prompt is generated.

[0085] Furthermore, the privacy-preserving mobile IoT device group signature system provided by the present invention will be described below. The privacy-preserving mobile IoT device group signature system described below can be referred to in correspondence with the privacy-preserving mobile IoT device group signature method described above.

[0086] Optional, refer to Figure 2 , Figure 2 This is a schematic diagram of the privacy-preserving mobile IoT device group signature system provided by the present invention. The privacy-preserving mobile IoT device group signature system includes: The key distribution module 210 is used to obtain the group initialization parameters generated by the issuer and distribute the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key and the group public key; The event token generation and change judgment module 220 is used to determine the current event token of the target device based on the group signature key and the preset event definition rules, and to judge whether the event of the target vehicle has changed based on the event token, and obtain the judgment result. The layered signature generation module 230 is used to sign based on the group signature key and the current event token to obtain a group signature if the judgment result is yes; and to sign based on the previously successfully obtained group signature and the current event token to obtain an event signature if the judgment result is no. The valid verification and privacy revocation module 240 is used to verify the group signature or event signature based on the group public key and the current event token to obtain a valid group signature or valid event signature, and to revoke privacy based on the master unlocking key and the registration information of the target device combined with the valid group signature to obtain the corresponding traceability result.

[0087] This invention obtains a unique group signature key bound to the group initialization parameters by acquiring the group initialization parameters generated by the issuer and allocating a group signature key. Based on this group signature key and preset event definition rules, the current event token suitable for the target vehicle is determined, thereby judging whether the event has changed and obtaining an accurate event change judgment result. Based on this judgment result, a flexible signature method is selected: when the event has changed, the current group signature key and the current event token are used for signing; when the event has not changed, the previous group signature key and the current event token are used for signing. This eliminates the need to repeatedly use the same group key for signing each time, effectively reducing the computational overhead in the signing process. Finally, the group public key and the current event token are used to... The signature is effectively verified, ensuring its validity while controlling the computational complexity of the verification phase. By combining the master unlocking key, target device registration information, and signature, privacy revocation is performed and traceability results are obtained. This solves the problems of high computational overhead, low communication efficiency, and impact on real-time response performance caused by the unified group key in existing methods. It also balances the relationship between privacy protection and identity traceability, achieving the effect of tracing the real identity through privacy revocation when necessary, while strengthening privacy protection by relying on exclusive keys and dynamic tokens. Furthermore, the dynamic adjustment of the signature method through event tokens flexibly controls the scope and duration of identity linkability, meeting the dynamically changing privacy protection needs in mobile IoT scenarios.

[0088] Please see Figure 3 , Figure 3 An embodiment diagram of an electronic device provided in accordance with the present invention. For example... Figure 3As shown, this embodiment of the invention provides an electronic device 300, including a memory 310, a processor 320, and a computer program 311 stored in the memory 310 and executable on the processor 320. When the processor 320 executes the computer program 311, it performs the following steps: Obtain the group initialization parameters generated by the issuer, and allocate the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key, and the group public key; Based on the group signature key and the preset event definition rules, the current event token of the target device is determined, and the event token is used to determine whether the event of the target vehicle has changed, and the determination result is obtained. If the judgment result is yes, then the group signature is obtained by signing based on the group signature key and the current event token; if the judgment result is no, then the event signature is obtained by signing based on the previously successfully obtained group signature and the current event token. The group signature or event signature is verified based on the group public key and the current event token to obtain a valid group signature or a valid event signature. Privacy revocation is then performed based on the master unlocking key and the registration information of the target device, combined with the valid group signature, to obtain the corresponding traceability result.

[0089] Please see Figure 4 , Figure 4 An embodiment diagram of a computer-readable storage medium provided in accordance with an embodiment of the present invention is shown. Figure 4 As shown, this embodiment provides a computer-readable storage medium 400 on which a computer program 311 is stored. When the computer program 311 is executed by a processor, it performs the following steps: Obtain the group initialization parameters generated by the issuer, and allocate the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key, and the group public key; Based on the group signature key and the preset event definition rules, the current event token of the target device is determined, and the event token is used to determine whether the event of the target vehicle has changed, and the determination result is obtained. If the judgment result is yes, then the group signature is obtained by signing based on the group signature key and the current event token; if the judgment result is no, then the event signature is obtained by signing based on the previously successfully obtained group signature and the current event token. The group signature or event signature is verified based on the group public key and the current event token to obtain a valid group signature or a valid event signature. Privacy revocation is then performed based on the master unlocking key and the registration information of the target device, combined with the valid group signature, to obtain the corresponding traceability result.

[0090] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the privacy-preserving mobile Internet of Things device group signature method provided by the above methods, the method comprising: Obtain the group initialization parameters generated by the issuer, and allocate the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key, and the group public key; Based on the group signature key and the preset event definition rules, the current event token of the target device is determined, and the event token is used to determine whether the event of the target vehicle has changed, and the determination result is obtained. If the judgment result is yes, then the group signature is obtained by signing based on the group signature key and the current event token; if the judgment result is no, then the event signature is obtained by signing based on the previously successfully obtained group signature and the current event token. The group signature or event signature is verified based on the group public key and the current event token to obtain a valid group signature or a valid event signature. Privacy revocation is then performed based on the master unlocking key and the registration information of the target device, combined with the valid group signature, to obtain the corresponding traceability result.

[0091] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0092] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A privacy-preserving method for group signature of mobile IoT devices, characterized in that, include: Obtain the group initialization parameters generated by the issuer, and allocate a group signature key to the target device applying to join the group based on the group initialization parameters; Group initialization parameters include the master issuing key, the master unlocking key, and the group public key; Based on the group signature key and the preset event definition rules, the current event token of the target device is determined, and the event token is used to determine whether the event of the target vehicle has changed, and the determination result is obtained. If the judgment result is yes, then a signature is obtained based on the group signature key and the current event token; If the result is negative, then the event signature is obtained by signing based on the previously successfully obtained group signature and the current event token; The group signature or event signature is verified based on the group public key and the current event token to obtain a valid group signature or a valid event signature. Privacy revocation is then performed based on the master unlocking key and the registration information of the target device, combined with the valid group signature, to obtain the corresponding traceability result.

2. The privacy-preserving mobile IoT device group signature method according to claim 1, characterized in that, The determination of the target device's current event token based on the group signature key combined with preset event definition rules includes: Cryptographic binding is performed based on the group signature key and the device identity of the target device to obtain the context parameters of the device-specific event; The current event type is obtained by matching the context parameters and the event types in the event definition rules. Based on the current event type and the context parameters, a structured encapsulation is performed to obtain an event semantic structure; The current event token of the target device is obtained by hash binding based on the event semantic structure and the group signature key.

3. The privacy-preserving mobile IoT device group signature method according to claim 1, characterized in that, The event semantic structure includes an event type identifier, device identity context information, and event occurrence logical context.

4. The privacy-preserving mobile IoT device group signature method according to claim 1, characterized in that, The process of obtaining an event signature based on the previously successfully obtained group signature and the current event token includes: Based on the previously successfully obtained group signature and the current event token, standardized cryptographic concatenation and binding are performed to obtain the signature binding input; Based on the signature binding input and the group signature key, perform encrypted signature processing to obtain the original signature; The event signature is obtained by structurally encapsulating and encoding the original signature and the current event token.

5. The privacy-preserving mobile IoT device group signature method according to claim 1, characterized in that, The process of validly verifying the group signature or event signature based on the group public key and the current event token to obtain a valid group signature or valid event signature includes: Based on the current event token and the received signature to be verified, the signature header field is parsed and the type identifier is extracted to obtain the signature type; If the signature type is a group signature, the group signature validity is verified based on the group public key and the current event token to obtain the first verification result; If the signature type is an event signature, then the binding and legality are double-checked based on the group public key, the current event token, and the group signature obtained in the last successful transaction, to obtain the second verification result; Based on the first verification result or the second verification result, a valid signature mark and state encapsulation are performed to obtain the valid group signature or the valid event signature.

6. The privacy-preserving mobile IoT device group signature method according to claim 1, characterized in that, The privacy revocation based on the master unlocking key and the target device's registration information combined with the group signature yields the corresponding traceability results, including: Based on the valid group signature and the master unlocking key, perform group signature decryption mapping to obtain the device anonymous identifier; Based on the anonymous identifier of the device and the registration information of the target device, a matching query is performed in conjunction with a pre-built registration information database to obtain the true identity information of the target device; Based on the valid group signature, device anonymity identifier, and real identity information, a structured encapsulation is performed to obtain the identity ownership proof; Based on the identity ownership proof and the group public key, an adjudication verification is performed to obtain an adjudication result. Based on the adjudication result being true, the tracing result is encapsulated and the event context is supplemented to obtain a tracing result containing real identity information.

7. The privacy-preserving mobile IoT device group signature method according to claim 6, characterized in that, If the ruling is false, a traceability failure message will be generated directly.

8. A privacy-preserving mobile IoT device group signature system, characterized in that, Applied to the privacy-preserving mobile IoT device group signature method as described in any one of claims 1 to 7; The privacy-preserving mobile IoT device group signature system includes: The key distribution module is used to obtain the group initialization parameters generated by the issuer and distribute the group signature key to the target device applying to join the group based on the group initialization parameters; the group initialization parameters include the master issuing key, the master unlocking key and the group public key; The event token generation and change judgment module is used to determine the current event token of the target device based on the group signature key and the preset event definition rules, and to judge whether the event of the target vehicle has changed based on the event token, and obtain the judgment result. The layered signature generation module is used to sign the event signature based on the group signature key and the current event token if the judgment result is yes; if the judgment result is no, it is used to sign the event signature based on the previously successfully obtained group signature and the current event token. The valid verification and privacy revocation module is used to verify the group signature or event signature based on the group public key and the current event token to obtain a valid group signature or valid event signature, and to revoke privacy based on the master unlocking key and the registration information of the target device combined with the valid group signature to obtain the corresponding traceability result.

9. An electronic device, characterized in that, include: Memory, used to store computer software programs; A processor is configured to read and execute the computer software program, wherein when the processor executes the computer software program, it implements the privacy-preserving mobile Internet of Things device group signature method as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, characterized in that, The storage medium stores a computer software program, which, when executed by a processor, implements the privacy-preserving mobile Internet of Things device group signature method as described in any one of claims 1 to 7.

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