A data security transmission method and system in a vehicle networking environment
By introducing congestion era division and hierarchical key derivation mechanism in the vehicle-to-everything (V2X) environment and dynamically adjusting the key update strategy, the problem of reduced security protection capability caused by untimely key updates in V2X is solved, and the security stability and transmission efficiency of the system are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 天津仁爱学院
- Filing Date
- 2025-09-02
- Publication Date
- 2026-06-23
AI Technical Summary
In high-density traffic scenarios of the Internet of Vehicles, the scarcity of channel resources and the fixed-period key mechanism lead to untimely key updates, creating a window of opportunity for attacks and resulting in a decline in security protection capabilities.
By introducing a congestion epoch division and a stable vehicle queue identification mechanism, the trusted communication range is dynamically determined. A hierarchical key derivation mechanism is adopted to perform hierarchical authentication and aggregate digest of secure broadcast messages, including multi-level derivation of congestion epoch number, anchor key, high-frequency information key and local subkey. Combined with the channel occupancy rate change rate, the hash algorithm is dynamically selected to ensure authentication security and transmission efficiency.
To improve the security, stability, and transmission efficiency of the system in complex traffic environments, avoid the decline in chain authentication efficiency, reduce the complexity of key management, and achieve rapid response and enhanced security strength in the face of instantaneous high-risk environments.
Smart Images
Figure CN120980524B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of data security transmission technology, specifically a data security transmission method and system in a vehicle-to-everything (V2X) environment. Background Technology
[0002] Vehicle-to-everything (V2X) technology enables collaborative traffic safety, intelligent scheduling, and information sharing through wireless communication between vehicles and between vehicles and roadside units. However, in complex and dynamic traffic environments, especially in scenarios with high vehicle density and frequent topology changes, communication links are highly vulnerable to eavesdropping, identity spoofing, and man-in-the-middle attacks.
[0003] Existing secure communication mechanisms typically rely on fixed-period key rotation. This mechanism cannot flexibly adjust to instantaneous changes in risk, providing attackers with a exploitable window of opportunity. Furthermore, in high-density traffic, communication frequencies increase significantly, channel resources become scarce, and systems, while ensuring basic broadcast and routing functions, often passively extend key update cycles or reduce encryption strength, further weakening security. Attackers can exploit this security window to disrupt the integrity and reliability of information transmission by forging node identities or inserting malicious data.
[0004] Therefore, there is an urgent need for a data security transmission method and system in the vehicle-to-everything (V2X) environment that can effectively compress the time window for attacks while ensuring communication continuity and improve the system's protection capabilities in instantaneous high-risk environments. Summary of the Invention
[0005] (1) Technical problems to be solved
[0006] The purpose of this invention is to provide a data security transmission method and system in a vehicle-to-everything (V2X) environment, in order to solve the problem that in high-density traffic scenarios of V2X, the shortage of channel resources and the fixed-period key mechanism lead to untimely key updates, which in turn create a time window for attacks and cause a decline in security protection capabilities.
[0007] (2) Technical solution
[0008] To achieve the above objectives, in one aspect, the present invention provides a method for secure data transmission in a vehicle-to-everything (V2X) environment, the method comprising:
[0009] Step S1: Obtain the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculate the linear density and relative speed characteristic value of consecutive adjacent vehicles in the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, generate a stable vehicle queue identifier and calculate the channel occupancy rate based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, determine that a congestion era has begun.
[0010] Step S2: Determine the congestion epoch number based on the stable vehicle queue identifier, timestamp, and road segment identifier; obtain the anchor key established by the vehicle, adjacent vehicles, and roadside units; perform key derivation on the anchor key and congestion epoch number to obtain a high-frequency information key and a local subkey bound to the vehicle identifier.
[0011] Step S3: Construct anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs and broadcasts the anchor message content; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; verify the chain authentication record to obtain the anchor message authentication record; perform symmetric authentication on the secure broadcast message based on the high-frequency information key and aggregate to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, authenticate the vehicle entry / exit event based on the local subkey, generate a vehicle entry / exit record, and synchronously update the local subkeys of the vehicle and adjacent vehicles.
[0012] Step S4: At the end of the congestion epoch, the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record are used to obtain the anchor key seed for the next congestion epoch through key advancement operation; the anchor key seed for the next congestion epoch is used to obtain the anchor key for the next congestion epoch through initialization derivation operation.
[0013] Furthermore, the method for determining the congestion era number based on the stable vehicle queue identifier, timestamp, and road segment identifier includes:
[0014] The timestamp of the moment when congestion begins is obtained through the vehicle's local synchronization clock. This timestamp is then divided into continuous, non-overlapping time segments according to a preset time resolution. The time segment number where the congestion begins is obtained as the basic congestion era number. This basic congestion era number is combined with the stable vehicle queue identifier, the timestamp, and the road segment identifier in a preset concatenation order to obtain the original congestion era number data. A checksum is calculated on the original congestion era number data to obtain a checksum. This checksum is then appended to the original congestion era number data to obtain the congestion era number.
[0015] Furthermore, the method for deriving a high-frequency information key and a local subkey bound to the vehicle identifier from the anchor key and the congestion epoch number includes:
[0016] The anchor key and the congestion epoch number are concatenated in a preset byte order to obtain the derived original data; multiple rounds of key derivation function operations are performed on the derived original data to obtain the derived output sequence; the target derived value is selected from the derived output sequence according to a preset index rule as the high-frequency information key; the high-frequency information key is combined with the vehicle identifier to further derive a local subkey.
[0017] Furthermore, the method for constructing the anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier includes:
[0018] Cryptographic operations are performed on the high-frequency information key to obtain a binding credential; the binding credential, congestion epoch number, and stable vehicle queue identifier are combined according to a preset field order to obtain the anchor message content.
[0019] Furthermore, the method for obtaining the binding credential by performing cryptographic operations on the high-frequency information key includes:
[0020] The channel occupancy rate is monitored in real time according to the preset sampling period.
[0021] When the channel occupancy rate change rate exceeds the preset mutation threshold, the binding credential is obtained by performing BLAKE3 hash algorithm operation on the concatenated data of high-frequency information key and random number.
[0022] When the channel occupancy rate change rate does not exceed the preset mutation threshold, the binding credential is obtained by performing a SHA3-256 hash operation on the concatenated data of the high-frequency information key and the random number.
[0023] Furthermore, the method for obtaining the binding credential by performing a BLAKE3 hash algorithm operation on the concatenated data of the high-frequency information key and the random number includes:
[0024] The concatenated data is processed using the BLAKE3 hash algorithm to obtain a 256-bit hash value; a 160-bit short hash value is obtained by truncation of the 256-bit hash value using a bitmask; a Merkle tree is constructed based on the 256-bit hash value, and the 256-bit hash value is used as a leaf node; the path node sequence connecting the leaf node to the root node and the hash values of the sibling nodes of each path node are combined according to a preset path order to obtain a path containing the proof.
[0025] The root node hash value is digitally signed using the vehicle's temporary private key to obtain the root node signature; the 160-bit short hash value, containing the proof path, and the root node signature are combined to obtain the binding credential.
[0026] Furthermore, the method for performing symmetric authentication of secure broadcast messages based on the high-frequency information key and aggregating them to obtain digest records includes:
[0027] Within the congestion period, all secure broadcast messages are received within a preset time window; each secure broadcast message is symmetrically authenticated according to the high-frequency information key to generate an authentication result sequence; the authentication result sequence is sorted by message sequence number and then cryptographically hashed to obtain a hash value sequence; the hash value sequence is sequentially accumulated into a digest chain structure according to the preset message order; the final hash value of the digest chain structure at the end of the time window is taken as the digest record.
[0028] Furthermore, the method for obtaining the anchor key seed for the next congestion era at the end of a congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry / exit queue record through key propagation operation includes:
[0029] The high-frequency information key is subjected to multiple iterative hash operations to obtain the key propulsion base value; the key propulsion base value is concatenated with the digest value of the anchor message authentication record, the final hash value of the digest record, and the digest value of the vehicle entry and exit queue record in a preset digest order to obtain propulsion input data; the propulsion input data is subjected to key derivation function operation to obtain the anchor key seed for the next congestion era.
[0030] Furthermore, the method for performing key derivation function operations on the input data to obtain the anchor key seed for the next congestion epoch includes:
[0031] The total number of authenticated messages is obtained by counting the number of successfully verified security broadcast messages based on the anchor message authentication record; the base salt value is determined based on the congestion epoch trigger number; when the total number of authenticated messages exceeds the preset high load threshold, the additional salt value is determined based on the unified clock time at the end of the congestion epoch.
[0032] When the total number of certified messages does not exceed a preset high load threshold, an additional salt value is determined based on the hash aggregation result of the identifiers of all vehicle nodes participating in the Congestion Era communication.
[0033] The base salt value and the additional salt value are concatenated in a preset salt value order to obtain the final salt value; the final salt value and the push input data are processed by the key derivation function to obtain the anchor key seed for the next congestion era.
[0034] Based on the same inventive concept, this invention also provides a data security transmission system in a vehicle-to-everything (V2X) environment, the system comprising:
[0035] The congestion determination module is used to acquire the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculate the linear density and relative speed characteristic value of consecutive adjacent vehicles in the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, generate a stable vehicle queue identifier and calculate the channel occupancy rate based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, determine that a congestion era has begun.
[0036] The key derivation module is used to determine the congestion epoch number based on the stable vehicle queue identifier, timestamp, and road segment identifier; obtain the anchor key established by the vehicle with adjacent vehicles and roadside units; and perform key derivation on the anchor key and congestion epoch number to obtain a high-frequency information key and a local subkey bound to the vehicle identifier.
[0037] The message authentication module is used to construct anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs the anchor message content and broadcasts it; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; the chain authentication record is verified to obtain the anchor message authentication record; the secure broadcast message is symmetrically authenticated based on the high-frequency information key and aggregated to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, the vehicle entry / exit event is authenticated based on the local subkey, a vehicle entry / exit record is generated, and the local subkeys of the vehicle and adjacent vehicles are updated synchronously.
[0038] The key advancement module is used to obtain the anchor key seed for the next congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record through key advancement operation at the end of the congestion era; and to obtain the anchor key for the next congestion era by using the anchor key seed for the next congestion era through initialization derivation operation.
[0039] (3) Beneficial effects
[0040] Compared with the prior art, the beneficial effects of the present invention are:
[0041] 1. By introducing the division of congestion eras and a stable vehicle queue identification mechanism, a reliable communication range can be dynamically determined in complex traffic environments, avoiding the problem of reduced chain authentication efficiency caused by frequent vehicle entry and exit, thereby improving the security and stability of the system.
[0042] 2. By implementing hierarchical authentication and aggregated digests for secure broadcast messages through a hierarchical derivation mechanism of anchor key, high-frequency information key, and local subkey, the complexity of key management can be reduced while ensuring authentication security, thereby improving transmission efficiency and scalability in the vehicle-to-everything (V2X) environment. Attached Figure Description
[0043] Figure 1 This is a flowchart of a data security transmission method in a vehicle-to-everything (V2X) environment according to Embodiment 1 of the present invention;
[0044] Figure 2 This is a schematic diagram of a data security transmission system in a vehicle networking environment according to Embodiment 2 of the present invention. Detailed Implementation
[0045] 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.
[0046] Before providing examples, it is necessary to describe the application scenarios of this invention. This invention targets high-density traffic flow scenarios during peak urban traffic hours, and is particularly suitable for areas where vehicles frequently start and stop, and where communication links fluctuate drastically, such as intersections of urban expressway ramps and main roads. In such environments, vehicles and roadside units need to continuously exchange safety-critical information such as collision warnings and coordinated lane-changing instructions. However, the surge in communication requests can easily lead to channel resource shortages. Traditional fixed-period security mechanisms are often forced to extend the key derivation interval or reduce computational complexity when the computational load is too high, thus creating security gaps that attackers can exploit. This solution dynamically senses the coupling relationship between traffic flow and channel status, and based on congestion epoch triggering and a multi-level key derivation mechanism, it ensures the continuity of basic vehicle communication while achieving rapid response to instantaneous high-risk scenarios, effectively solving the core contradiction of balancing security strength and real-time communication under resource-constrained conditions.
[0047] Example 1: As Figure 1 As shown, this embodiment provides a method for secure data transmission in a vehicle-to-everything (V2X) environment, the method comprising:
[0048] Step S1: Obtain the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculate the linear density and relative speed characteristic value of consecutive adjacent vehicles in the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, generate a stable vehicle queue identifier and calculate the channel occupancy rate based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, determine that a congestion era has begun.
[0049] Step S2: Determine the congestion epoch number based on the stable vehicle queue identifier, timestamp, and road segment identifier; obtain the anchor key established by the vehicle, adjacent vehicles, and roadside units; perform key derivation on the anchor key and congestion epoch number to obtain a high-frequency information key and a local subkey bound to the vehicle identifier.
[0050] Step S3: Construct anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs and broadcasts the anchor message content; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; verify the chain authentication record to obtain the anchor message authentication record; perform symmetric authentication on the secure broadcast message based on the high-frequency information key and aggregate to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, authenticate the vehicle entry / exit event based on the local subkey, generate a vehicle entry / exit record, and synchronously update the local subkeys of the vehicle and adjacent vehicles.
[0051] Step S4: At the end of the congestion epoch, the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record are used to obtain the anchor key seed for the next congestion epoch through key advancement operation; the anchor key seed for the next congestion epoch is used to obtain the anchor key for the next congestion epoch through initialization derivation operation.
[0052] When road traffic flow decreases, for example, when the linear density is lower than the preset congestion threshold, the relative speed characteristic value is higher than the preset stability threshold, or the channel occupancy rate is lower than the preset occupancy threshold, the congestion era is considered to have ended.
[0053] In this embodiment, the preset congestion threshold is set at 100 vehicles / km for main roads according to the "Design Code for Urban Expressways". The stability threshold adopts the upper limit of the standard deviation of relative speed of vehicle queues as specified in ISO 15622:2018, which is 5 km / h. The continuous adjacent judgment criterion adopts the 5m safe following distance defined in ISO 15622:2018. When the distance between vehicles is ≤5m, they are included in the continuous queue. When the linear density of the vehicle position sequence obtained by millimeter-wave radar reaches 125 vehicles / km and exceeds the preset congestion threshold of 100 vehicles / km, and the relative speed characteristic value is 3.2 km / h and less than the 5km / h stability threshold, the system automatically generates a stable vehicle queue identifier VQ-038 according to the preset queue rules. At the same time, the DSRC module monitors the channel occupancy rate to reach 88%, which exceeds the 85% threshold specified in ETSI TS102687, triggering a congestion era. In this process, adjacent vehicles are defined as all nodes within one hop of the current vehicle's wireless communication, and the communication range does not exceed 300m.
[0054] For example, the congestion epoch number is generated by concatenating the stable queue identifier VQ-038, the UTC timestamp 1689156835070, the 10ms resolution segment 507, and the road segment identifier G6-07, and then performing a CRC-32 checksum, resulting in "507-VQ-038-G6-07-9B2F". The anchor key is derived from KDF-CTR to obtain 0x8F2C, which is concatenated with the congestion epoch number and then subjected to HMAC-SHA256 iterative operation. The output result of 256-383 bits is used as the high-frequency information key 0x4E9A. Subsequently, this high-frequency information key is combined with the vehicle VIN-LDCW3AE0 and subjected to HMAC-SHA256 operation to obtain the local subkey 0xC82B.
[0055] The high-frequency information key is also used to generate binding credentials. The hash algorithm is dynamically selected based on the channel occupancy rate change rate; BLAKE3 is used when the change rate exceeds a threshold, otherwise SHA3-256 is used to obtain the initial binding credential. This credential is further processed through a Merkle tree to obtain a 160-bit short hash and proof path, and the root node is signed by the vehicle's temporary private key to form a complete binding credential. Secure broadcast messages undergo symmetric authentication using the high-frequency information key. The authentication results are sorted by message sequence number, hashed one by one, and accumulated into a digest chain structure. At the end of a 200ms window, the final hash value is taken as the digest record; an example is 0x4F6A.
[0056] At the end of the congestion era, the high-frequency information key 0x4E9A, the chained authentication digest 0x8F3D, the digest record 0x4F6A, and the entry / exit queue records all participate in the key propagation operation. Specifically, the high-frequency information key is iteratively hashed multiple times and then concatenated with the aforementioned digest information. A salt value generated based on the information load is used as input; under high load, the salt value is generated by a unified clock, while under low load, it is generated by aggregating vehicle identifiers. The final propagation input data is processed through KDF operations to obtain the anchor key seed 0x9D4A. Subsequently, an initialization derivation operation is performed to generate the anchor key for the next congestion era. This initialization derivation operation can be implemented using standardized KDF functions such as HKDF-Expand.
[0057] The method for determining the congestion era number based on the stable vehicle queue identifier, timestamp, and road segment identifier includes:
[0058] The timestamp of the moment when congestion begins is obtained through the vehicle's local synchronization clock; the timestamp is divided into continuous, non-overlapping time segments according to a preset time resolution; the time segment number where the moment when congestion begins is obtained is used as the basic congestion era number; the basic congestion era number is combined with the stable vehicle queue identifier, the timestamp, and the road segment identifier according to a preset splicing order to obtain the original data of the congestion era number; a checksum is calculated on the original data of the congestion era number to obtain a checksum; the checksum is appended to the original data of the congestion era number to obtain the congestion era number.
[0059] The time resolution is fixed at 10ms to match the synchronization accuracy of the vehicle's CAN bus clock. The trigger time GPS timestamp 1689156835070 is moduloed according to this resolution to obtain the basic number 507. The basic number 507 is concatenated with the stable vehicle queue identifier VQ-038, the complete timestamp 1689156835070, and the road segment identifier G6-07 in the preset concatenation order "Congestion Era Basic Number - Stable Vehicle Queue Identifier - Timestamp - Road Segment Identifier" to form "507-VQ-038-1689156835070-G6-07". After CRC-32 verification, a checksum of 0x9B2F is generated, finally obtaining the congestion era number "507-9B2F". CRC-32 has a low collision rate and meets the uniqueness guarantee.
[0060] For example, in the scenario of the entrance ramp of the G6 urban expressway, the queue identifier VQ-038 of a 5-vehicle platoon is concatenated together with the road identifier G6-07. The timestamp 1689156835070 corresponds to the UTC time 2025-08-15 18:30:25.070, which yields the base number 507 at a 10ms resolution. The checksum 0x9B2F is calculated using CRC-32 and appended to the base number to form the final epoch number "507-9B2F". The "507-9B2F" shown in this embodiment is merely an exemplary representation used to illustrate the numbering logic.
[0061] The method for deriving a high-frequency information key and a local subkey bound to a vehicle identifier from the anchor key and the congestion epoch number includes:
[0062] The anchor key and the congestion epoch number are concatenated in a preset byte order to obtain the derived original data; multiple rounds of key derivation function operations are performed on the derived original data to obtain the derived output sequence; the target derived value is selected from the derived output sequence according to a preset index rule as the high-frequency information key; the high-frequency information key is combined with the vehicle identifier to further derive a local subkey.
[0063] The anchor key 0x8F2C and the epoch number "507-9B2F" are concatenated in predefined big-endian byte order to form the derived input, which is then iteratively processed using KDF-CTR mode to output a 512-bit sequence. The indexing rules of the derived output sequence conform to the selection method of standardized KDF; for example, bits 256 to 383 are truncated as the high-frequency information key 0x4E9A for authentication of global broadcast messages. The derivation of the local subkey uses a single-round HMAC-SHA256 operation, concatenating the high-frequency key 0x4E9A with the vehicle's unique identifier VIN-LDCW3AE0 to generate a 256-bit vehicle-specific subkey 0xC82B, used for signature verification during the vehicle's entry and exit from the stable vehicle queue.
[0064] For example, when the high-frequency key 0x4E9A is concatenated with the VIN code, the local subkey 0xC82B of vehicle VIN-LDCW3AE0 in queue VQ-038 can be obtained through HMAC-SHA256 operation. When a vehicle changes lanes and leaves the queue, this key immediately becomes invalid and is updated, and its authentication status is written into the epoch data structure as a vehicle entry and exit record. This record enters the advance input data at the end of the epoch and participates in the key advancement operation together with the anchor message authentication record and digest record, thereby realizing a closed-loop connection between vehicle-level authentication and epoch-level key evolution.
[0065] The method for constructing anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier includes:
[0066] Cryptographic operations are performed on the high-frequency information key to obtain a binding credential; the binding credential, congestion epoch number, and stable vehicle queue identifier are combined according to a preset field order to obtain the anchor message content.
[0067] The default field order is fixed in the system as "binding credential – epoch number – queue identifier" to ensure that messages generated by different vehicles and in different epoch environments have a unified structure and verifiability.
[0068] For example, the high-frequency information key 0x4E9A is processed by a preset hash algorithm to generate a binding credential 0xC82B1F; the current congestion epoch number is "507-9B2F", and the stable vehicle queue identifier is VQ-038. These three are concatenated sequentially to obtain the anchor message content: "0xC82B1F-507-9B2F-VQ-038". This message content serves as a unified anchor point during broadcasting, ensuring that subsequent digest and authentication operations are traceable and tamper-proof.
[0069] The method for obtaining the binding credential by performing cryptographic operations on the high-frequency information key includes:
[0070] The channel occupancy rate is monitored in real time according to the preset sampling period.
[0071] When the channel occupancy rate change rate exceeds the preset mutation threshold, the binding credential is obtained by performing BLAKE3 hash algorithm operation on the concatenated data of high-frequency information key and random number.
[0072] When the channel occupancy rate change rate does not exceed the preset mutation threshold, the binding credential is obtained by performing a SHA3-256 hash operation on the concatenated data of the high-frequency information key and the random number.
[0073] The generation of binding credentials employs a channel state adaptive mechanism. Based on ETSI TR 102 861 channel transient data, the system sets the channel occupancy rate change threshold to ±5% / ms. During operation, this change rate is monitored in real time. When the detected value exceeds ±5% / ms, a BLAKE3 hash operation is performed on the concatenated data of the high-frequency information key and a random number; when the detected value does not exceed this threshold, a SHA3-256 hash operation is performed. Subsequently, the generated binding credentials are combined with the congestion epoch number and the stable vehicle queue identifier in the field order of "credential-number-queue ID" to form an anchor message content with tamper-resistant properties. This mechanism achieves a balance between real-time performance and security by dynamically switching hash algorithms under different channel load conditions.
[0074] For example, in one detection, the high-frequency information key is 0x4E9A, the channel change rate is +6.2% / ms, which is higher than the threshold of 1.2%. The system generates a random number 0x5D1F and concatenates it with the high-frequency information key in accordance with the requirements of GB / T 32915-2016. The BLAKE3 hash operation is performed to obtain a 256-bit output 0xC82B. The first 160 bits are truncated to form a short hash value 0xC82B1F. Then, the binding certificate is combined with the epoch number "507-9B2F" and the queue identifier VQ-038 to obtain the anchor message content "0xC82B1F-507-9B2F-VQ-038".
[0075] The method for obtaining the binding credential by performing a BLAKE3 hash algorithm operation on the concatenated data of the high-frequency information key and the random number includes:
[0076] The concatenated data is processed using the BLAKE3 hash algorithm to obtain a 256-bit hash value; a 160-bit short hash value is obtained by truncation of the 256-bit hash value using a bitmask; a Merkle tree is constructed based on the 256-bit hash value, and the 256-bit hash value is used as a leaf node; the path node sequence connecting the leaf node to the root node and the hash values of the sibling nodes of each path node are combined according to a preset path order to obtain a path containing the proof.
[0077] The root node hash value is digitally signed using the vehicle's temporary private key to obtain the root node signature; the 160-bit short hash value, containing the proof path, and the root node signature are combined to obtain the binding credential.
[0078] The random number is generated in real time by the vehicle security chip according to the GB / T 32915-2016 standard. The output of the BLAKE3 hash operation is first truncated to a 160-bit short hash value through a bitmask. Then, a Merkle tree is constructed using the original 256-bit hash value as the leaf nodes, and the root node hash 0x9E04 is generated according to the RFC 9162 specification. The path node sequence from the leaf node to the root node is combined with the sibling node hash values to form a complete proof path. The root node is then signed by the vehicle's temporary private key based on the GM / T0003.2SM2 algorithm to obtain the signature value 0x3045. The final binding credential consists of the short hash value, the proof path, and the root node signature. The path order is fixed, arranged sequentially from the leaf node to the root node, and the sibling node hashes at each level are combined according to the Merkle tree standard, with the left node taking precedence over the right node.
[0079] For example, when the leaf node value is 0xC82B, the corresponding path node sequence in the constructed Merkle tree is [0x5C21, 0x8A9F], the sibling node hash value is [0x3D7E, 0xF209], the root node hash is 0x9E04, and the signature result is 0x3045. The output binding credential in this case is composed of the short hash value 0xC82B1F, the path and hash pair [0x5C21:0x3D7E, 0x8A9F:0xF209], and the signature value 0x3045.
[0080] The method for performing symmetric authentication of secure broadcast messages based on the high-frequency information key and aggregating them to obtain digest records includes:
[0081] Within the congestion period, all secure broadcast messages are received within a preset time window; each secure broadcast message is symmetrically authenticated according to the high-frequency information key to generate an authentication result sequence; the authentication result sequence is sorted by message sequence number and then cryptographically hashed to obtain a hash value sequence; the hash value sequence is sequentially accumulated into a digest chain structure according to the preset message order; the final hash value of the digest chain structure at the end of the time window is taken as the digest record.
[0082] During congestion periods, the system receives all security broadcast messages within a fixed 200ms time window, consistent with the multi-channel switching period defined in IEEE 1609.4. Received messages are first symmetrically authenticated one by one based on the high-frequency information key, generating corresponding authentication status codes, where 0x01 indicates successful authentication. Subsequently, all authentication results are sorted by message sequence number according to the ascending order rule of ISO 24102-5:2013, and each message is subjected to a SHA3-384 hash operation. The resulting hash value sequence is accumulated according to the concatenated structure of RFC 6962: the hash output of the previous round is concatenated with the hash value of the current message, and the hash is calculated again until the window ends, yielding the final output, which serves as the digest record for this time window. This process ensures the integrity of the message order and the immutability of the digest results.
[0083] For example, three messages received within a 200ms window are: Msg#1017 (authentication successful, hash value 0x8A2F), Msg#1018 (authentication successful, hash value 0xB3E1), and Msg#1019 (authentication successful, hash value 0x9F07). Using an initial value of 0x0000 as an accumulator, it is first concatenated with the hash value of message #1017 to calculate an intermediate result of 0xD45C. Then, it is concatenated with the hash value of message #1018 to calculate 0x7E29. Finally, it is concatenated with the hash value of message #1019 to calculate the final value of 0x4F6A. The final output digest record is 0x4F6A, with a timestamp of 1689156835200 appended.
[0084] The method for obtaining the anchor key seed for the next congestion era at the end of a congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry / exit queue record through key propagation operation includes:
[0085] The high-frequency information key is subjected to multiple iterative hash operations to obtain the key propulsion base value; the key propulsion base value is concatenated with the digest value of the anchor message authentication record, the final hash value of the digest record, and the digest value of the vehicle entry and exit queue record in a preset digest order to obtain propulsion input data; the propulsion input data is subjected to key derivation function operation to obtain the anchor key seed for the next congestion era.
[0086] At the end of the congestion epoch, the high-frequency information key 0x4E9A undergoes a triple HMAC-SHA256 iterative operation to generate the key propagation base value. Specifically, the first round of operation outputs 0xB82F, which serves as the input for the second round; the second round outputs 0x3D07, which serves as the input for the final round; the final round result is truncated to the first 192 bits, yielding the propagation base value 0x5A1E. The number of iteration rounds is preset to 3 by the security level to balance computational complexity and security. Simultaneously, the Merkle root node 0x9E04, anchoring the message authentication record, is hashed to 0x8F3D using SHA-256; the digest record for this epoch directly references 0x4F6A; and the event of vehicle VIN-LN86 joining the queue is hashed to 0xE7D2 using SHA-256. The system concatenates the above four results in a preset order to form the input data, namely 0x5A1E||0x8F3D||0x4F6A||0xE7D2, and controls the total length to within 512 bits to ensure that it meets the processing requirements of cryptographic devices.
[0087] For example, the specific steps of the advancement process include: the high-frequency information key 0x4E9A is processed by HMAC-SHA256 to obtain 0xB82F; 0xB82F is used as input to continue the operation to obtain 0x3D07; 0x3D07 is used as input, and the first 192 bits of the HMAC output are taken to obtain the advancement base value 0x5A1E. Subsequently, the anchor message authentication record digest 0x8F3D, the broadcast message digest 0x4F6A, and the vehicle entry / exit record digest 0xE7D2 are concatenated in the order of the preset key advancement base value, with the anchor message digest, broadcast digest, and entry / exit record digest in the first position, to obtain the final advancement input data 0x5A1E||0x8F3D||0x4F6A||0xE7D2.
[0088] The method for performing key derivation function operations on the input data to obtain the anchor key seed for the next congestion epoch includes:
[0089] The total number of authenticated messages is obtained by counting the number of successfully verified security broadcast messages based on the anchor message authentication record; the base salt value is determined based on the congestion epoch trigger number; when the total number of authenticated messages exceeds the preset high load threshold, the additional salt value is determined based on the unified clock time at the end of the congestion epoch.
[0090] When the total number of certified messages does not exceed a preset high load threshold, an additional salt value is determined based on the hash aggregation result of the identifiers of all vehicle nodes participating in the Congestion Era communication.
[0091] The base salt value and the additional salt value are concatenated in a preset salt value order to obtain the final salt value; the final salt value and the push input data are processed by the key derivation function to obtain the anchor key seed for the next congestion era.
[0092] At the end of a congestion epoch, the system counts the total number of security broadcast messages based on the authentication counter. When the count exceeds a preset high-load threshold of 80,000 messages, the UTC timestamp at the end of the epoch is used as the additional salt value; when the count does not exceed the preset high-load threshold, the result of aggregating the VIN identifiers of all vehicles participating in this epoch using SHA-256 hashing is used as the additional salt value. The base salt value is generated by performing an HKDF-Extract operation on the UTF-8 byte stream of the congestion epoch number. For example, when the epoch number is "507-9B2F", the generated value is 0x2C8F. The final salt value is obtained by concatenating the preset base salt value first, followed by the additional salt value, and filling it to 256 bits according to the GM / T 0006 specification to ensure that it meets the input requirements of cryptographic devices. The system then inputs the final salt value and the push input data into the HKDF-Expand function to complete the expansion according to the NIST SP800-56C standard, and outputs the anchor key seed for the next congestion epoch.
[0093] For example, in a simulation test, the total number of authentication messages reached 85,400, exceeding the preset high-load threshold. Therefore, the additional salt value was taken as the UTC time of the end of the epoch, "20250815T183025Z". The final salt value was 0x2C8F concatenated with this timestamp and padded with zeros to 256 bits. This salt value, along with the propulsion input data 0x5A1E||0x8F3D||0x4F6A||0xE7D2, was input into HKDF-Expand, and the final output anchor key seed was 0x9D4A. If the total number of authentication messages was 75,000, not exceeding the threshold of 80,000, the additional salt value was changed to the concatenated hash result of the VIN identifiers of all vehicles in the convoy. For example, VIN1 and VIN2 were concatenated, and then SHA-256 was performed to obtain 0x3A8F. After padding and concatenation, it was then entered into the key derivation expansion operation.
[0094] To verify the effectiveness of the technology, peak-situation tests were conducted on a vehicle-to-everything (V2X) simulation platform. The results show that the proposed solution has a shorter d1 key update latency compared to the traditional fixed-period mechanism; key management traffic on the RSU side is reduced by 41.8%. Under conditions of channel abrupt changes, the BLAKE3 hash algorithm reduces authentication latency by 67.3% compared to SHA3-256, meeting the real-time requirements of DSRC communication under high-density traffic conditions.
[0095] Example 2: Based on the same inventive concept, such as Figure 2 As shown, this embodiment also provides a data security transmission system in a vehicle-to-everything (V2X) environment, the system comprising:
[0096] The congestion determination module is used to acquire the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculate the linear density and relative speed characteristic value of consecutive adjacent vehicles in the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, generate a stable vehicle queue identifier and calculate the channel occupancy rate based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, determine that a congestion era has begun.
[0097] The key derivation module is used to determine the congestion epoch number based on the stable vehicle queue identifier, timestamp, and road segment identifier; obtain the anchor key established by the vehicle with adjacent vehicles and roadside units; and perform key derivation on the anchor key and congestion epoch number to obtain a high-frequency information key and a local subkey bound to the vehicle identifier.
[0098] The message authentication module is used to construct anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs the anchor message content and broadcasts it; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; the chain authentication record is verified to obtain the anchor message authentication record; the secure broadcast message is symmetrically authenticated based on the high-frequency information key and aggregated to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, the vehicle entry / exit event is authenticated based on the local subkey, a vehicle entry / exit record is generated, and the local subkeys of the vehicle and adjacent vehicles are updated synchronously.
[0099] The key advancement module is used to obtain the anchor key seed for the next congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record through key advancement operation at the end of the congestion era; and to obtain the anchor key for the next congestion era by using the anchor key seed for the next congestion era through initialization derivation operation.
[0100] It should be noted that the specific methods by which each module performs operations in the system described in the above embodiments have been described in detail in the embodiments related to the method, and will not be elaborated here.
[0101] Finally, it should be noted that although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for secure data transmission in a vehicle-to-everything (V2X) environment, characterized in that, The method includes: The system acquires the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculates the linear density and relative speed characteristic value of consecutive adjacent vehicles within the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, a stable vehicle queue identifier is generated and the channel occupancy rate is calculated based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, it determines that a congestion era has begun. The congestion epoch number is determined based on the stable vehicle queue identifier, timestamp, and road segment identifier; the anchor key established by the vehicle, adjacent vehicles, and roadside units is obtained; the anchor key and the congestion epoch number are used to derive a high-frequency information key and a local subkey bound to the vehicle identifier; Anchor message content is constructed based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs and broadcasts the anchor message content; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; the chain authentication record is verified to obtain the anchor message authentication record; the secure broadcast message is symmetrically authenticated based on the high-frequency information key and aggregated to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, the vehicle entry / exit event is authenticated based on the local subkey, a vehicle entry / exit record is generated, and the local subkeys of the vehicle and adjacent vehicles are updated synchronously. At the end of the congestion era, the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record are used to obtain the anchor key seed for the next congestion era through key advancement operation; the anchor key seed for the next congestion era is then used to obtain the anchor key for the next congestion era through initialization derivation operation.
2. The data security transmission method in a vehicle-to-everything (V2X) environment according to claim 1, characterized in that, The method for determining the congestion era number based on the stable vehicle queue identifier, timestamp, and road segment identifier includes: The timestamp of the moment when congestion begins is obtained through the vehicle's local synchronization clock; the timestamp is divided into continuous, non-overlapping time segments according to a preset time resolution; the time segment number where the moment when congestion begins is obtained is used as the basic congestion era number; the basic congestion era number is combined with the stable vehicle queue identifier, the timestamp, and the road segment identifier according to a preset splicing order to obtain the original data of the congestion era number; a checksum is calculated on the original data of the congestion era number to obtain a checksum; the checksum is appended to the original data of the congestion era number to obtain the congestion era number.
3. The data security transmission method in a vehicle-to-everything (V2X) environment according to claim 1, characterized in that, The method for deriving a high-frequency information key and a local subkey bound to a vehicle identifier from the anchor key and the congestion epoch number includes: The anchor key and the congestion epoch number are concatenated in a preset byte order to obtain the derived original data; multiple rounds of key derivation function operations are performed on the derived original data to obtain the derived output sequence; the target derived value is selected from the derived output sequence according to a preset index rule as the high-frequency information key; the high-frequency information key is combined with the vehicle identifier to further derive a local subkey.
4. The data security transmission method in a vehicle-to-everything (V2X) environment according to claim 1, characterized in that, The method for constructing anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier includes: Cryptographic operations are performed on the high-frequency information key to obtain a binding credential; the binding credential, congestion epoch number, and stable vehicle queue identifier are combined according to a preset field order to obtain the anchor message content.
5. A method for secure data transmission in a vehicle-to-everything (V2X) environment according to claim 4, characterized in that, The method for obtaining the binding credential by performing cryptographic operations on the high-frequency information key includes: The channel occupancy rate change rate is monitored in real time according to the preset sampling period; When the channel occupancy rate change rate exceeds the preset mutation threshold, the binding credential is obtained by performing BLAKE3 hash algorithm operation on the concatenated data of high-frequency information key and random number; When the channel occupancy rate change rate does not exceed the preset mutation threshold, the binding credential is obtained by performing a SHA3-256 hash operation on the concatenated data of the high-frequency information key and the random number.
6. A data security transmission method in a vehicle-to-everything (V2X) environment according to claim 5, characterized in that, The method for obtaining the binding credential by performing a BLAKE3 hash algorithm operation on the concatenated data of the high-frequency information key and the random number includes: The concatenated data is processed using the BLAKE3 hash algorithm to obtain a 256-bit hash value; a 160-bit short hash value is obtained by truncation of the 256-bit hash value using a bitmask; a Merkle tree is constructed based on the 256-bit hash value, and the 256-bit hash value is used as a leaf node; the path node sequence connecting the leaf node to the root node and the hash values of the sibling nodes of each path node are combined according to a preset path order to obtain a path containing the proof. The root node hash value is digitally signed using the vehicle's temporary private key to obtain the root node signature; the 160-bit short hash value, containing the proof path, and the root node signature are combined to obtain the binding credential.
7. A method for secure data transmission in a vehicle-to-everything (V2X) environment according to claim 1, characterized in that, The method for performing symmetric authentication of secure broadcast messages based on the high-frequency information key and aggregating them to obtain digest records includes: Within the congestion period, all secure broadcast messages are received within a preset time window; each secure broadcast message is symmetrically authenticated according to the high-frequency information key to generate an authentication result sequence; the authentication result sequence is sorted by message sequence number and then cryptographically hashed to obtain a hash value sequence; the hash value sequence is sequentially accumulated into a digest chain structure according to the preset message order; the final hash value of the digest chain structure at the end of the time window is taken as the digest record.
8. A method for secure data transmission in a vehicle-to-everything (V2X) environment according to claim 1, characterized in that, The method for obtaining the anchor key seed for the next congestion era at the end of a congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry / exit queue record through key propagation operation includes: The high-frequency information key is subjected to multiple iterative hash operations to obtain the key propulsion base value; the key propulsion base value is concatenated with the digest result of the anchor message authentication record, the final hash value of the digest record, and the digest result of the vehicle entry and exit queue record in a preset digest order to obtain propulsion input data; the propulsion input data is subjected to key derivation function operation to obtain the anchor key seed for the next congestion era.
9. A method for secure data transmission in a vehicle-to-everything (V2X) environment according to claim 8, characterized in that, The method for performing key derivation function operations on the input data to obtain the anchor key seed for the next congestion epoch includes: The total number of authenticated messages is obtained by counting the number of successfully verified security broadcast messages based on the anchor message authentication record; the base salt value is determined based on the congestion epoch trigger number; when the total number of authenticated messages exceeds the preset high load threshold, the additional salt value is determined based on the unified clock time at the end of the congestion epoch. When the total number of certified messages does not exceed a preset high load threshold, an additional salt value is determined based on the hash aggregation result of the identifiers of all vehicle nodes participating in the Congestion Era communication. The base salt value and the additional salt value are concatenated in a preset salt value order to obtain the final salt value; the final salt value and the push input data are processed by the key derivation function to obtain the anchor key seed for the next congestion era.
10. A data security transmission system in a vehicle-to-everything (V2X) environment, characterized in that, The system includes: The congestion determination module is used to acquire the position sequence and communication link status information of the vehicle itself, adjacent vehicles, and roadside units within a preset time window; calculate the linear density and relative speed characteristic value of consecutive adjacent vehicles in the road segment based on the position sequence; when the linear density is greater than a preset congestion threshold and the relative speed characteristic value is less than a preset stability threshold, generate a stable vehicle queue identifier and calculate the channel occupancy rate based on the communication link status information; when the channel occupancy rate is greater than a preset occupancy threshold, determine that a congestion era has begun. The key derivation module is used to determine the congestion epoch number based on the stable vehicle queue identifier, timestamp, and road segment identifier; obtain the anchor key established by the vehicle with adjacent vehicles and roadside units; and perform key derivation on the anchor key and congestion epoch number to obtain a high-frequency information key and a local subkey bound to the vehicle identifier. The message authentication module is used to construct anchor message content based on the congestion epoch number, high-frequency information key, and stable vehicle queue identifier; the vehicle at the forefront of the stable vehicle queue in the direction of travel signs the anchor message content and broadcasts it; subsequent vehicles verify the validity of the previous signature and append their own signature to form a chain authentication record; the chain authentication record is verified to obtain the anchor message authentication record; the secure broadcast message is symmetrically authenticated based on the high-frequency information key and aggregated to obtain a digest record; when a vehicle enters or leaves the stable vehicle queue, the vehicle entry / exit event is authenticated based on the local subkey, a vehicle entry / exit record is generated, and the local subkeys of the vehicle and adjacent vehicles are updated synchronously. The key advancement module is used to obtain the anchor key seed for the next congestion era by using the high-frequency information key, anchor message authentication record, digest record, and vehicle entry and exit queue record through key advancement operation at the end of the congestion era; and to obtain the anchor key for the next congestion era by using the anchor key seed for the next congestion era through initialization derivation operation.