A privacy protection method for Internet of Vehicles based on CNTR on NTRU lattice

Abstract

The present invention belongs to the field of information technology security of Internet of Vehicles (IoV), and relates to an IoV privacy protection method based on CNTR on the NTRU lattice, including S1, initialization settings, in which a trusted center configures system parameters; S2, vehicle registration, in which a vehicle is registered with a trusted center upon leaving the factory, and a current vehicle private key is generated; S3, road test unit registration, in which the public key of the road test unit uses the system public key broadcast by the trusted center, and the private key of the road test unit uses the system private key; S4, message signcryption, in which a signcrypted message is broadcast; S5, message designcryption, in which the road test unit obtains the signcrypted message sent by the vehicle and designcrypts it using the system private key. The present invention has the advantages of using NTRU lattice cryptography and ring signature technology to achieve quantum security protection for IoV vehicle and Internet of Everything (V2X) communications.

Description

Technical Field

[0001] The present invention belongs to the field of information technology security of Internet of Vehicles (IoV), and specifically relates to the application of post-quantum cryptography in vehicular communications, and in particular to an IoV privacy protection method using a lightweight key encapsulation mechanism based on the NTRU (Number Theory Research Unit) lattice. Background Art

[0002] With the rapid development of intelligent connected vehicles, data security and privacy protection in connected vehicle communications face unprecedented challenges. Current mainstream encryption technologies rely primarily on elliptic curve cryptography (such as ECDSA) and traditional public key cryptography (such as RSA). The vulnerability of these algorithms to quantum computing attacks has become a recognized industry concern. The unique computational mechanisms of quantum computers expose classical cryptographic systems to the risk of rapid cracking. For example, a quantum attack based on the Shor algorithm can dismantle existing encryption systems within hours, posing a serious threat to connected vehicle infrastructure, which requires long-term security.

[0003] Existing technologies have exposed three key flaws in practical applications. First, traditional post-quantum cryptographic schemes struggle to adapt to the resource constraints of in-vehicle devices. Typical in-vehicle microcontrollers (MCUs) typically have less than 16KB of memory and a 100MHz clock speed. However, the key generation process for mainstream quantum-resistant schemes, such as NTRU-HRSS, requires over 18 milliseconds of computation time, significantly exceeding the real-time requirements of connected vehicle communications. Second, the high noise environment of wireless channels renders existing lattice cryptographic schemes unreliable. In complex scenarios such as urban canyons, the bit error rate can reach 0.4%, leading to frequent decryption failures in schemes based on ideal lattice assumptions, directly impacting vehicle safety decisions. Finally, existing schemes suffer from widespread communication inefficiency. Excessively large ciphertext sizes exacerbate channel congestion, potentially leading to transmission delays of critical safety information in high-frequency vehicle-to-vehicle (V2V) communications.

[0004] While the traditional NTRU (Number Theory Research Unit) algorithm offers advantages in quantum resistance, the complex polynomial inversion operations involved in key generation severely limit performance. Taking the NTRU-HRSS scheme as an example, its multiple modular operations and iterations not only consume significant computing resources but also result in high memory usage. On the other hand, while solutions based on the ring learning error (RLWE) hypothesis (such as Kyber) have improved some performance metrics, their non-optimized modular structure compromises algorithmic efficiency and inherent flaws in side-channel protection. More importantly, existing solutions have failed to effectively address the issue of reliable communication in noisy environments and lack adaptive fault-tolerance mechanisms designed specifically for connected vehicle scenarios.

[0005] At the engineering implementation level, existing technical solutions lack compatibility with connected vehicle industry standards. Current in-vehicle communication protocols (such as ETSI TS 103097) and security frameworks (such as AutosarSecOC) have yet to fully integrate post-quantum cryptographic components, leading to architectural adaptation difficulties in real-world deployments. Furthermore, traditional security proofs are often based on idealized assumptions and fail to fully consider the unique attack surfaces of in-vehicle systems (such as the physical accessibility of OBU devices), leaving theoretical gaps in verifiable security.

[0006] The current challenge facing this field is how to maintain quantum security while meeting the stringent requirements of the connected vehicle (IoV) environment for algorithm efficiency, communication reliability, and device compatibility. Existing solutions often require trade-offs across various dimensions, and a comprehensive, systematic solution to this technical challenge has yet to emerge. This situation severely hinders the progress of security upgrades in IoV systems, leaving the industry on the defensive in addressing the threat of quantum computing. Summary of the Invention

[0007] In view of the above problems, the purpose of the present invention is to provide a privacy protection method for the Internet of Vehicles (IoV) based on CNTR (new key encapsulation mechanism) on the NTRU lattice, which adopts NTRU lattice cryptography and ring signature technology to realize quantum security protection of IoV vehicles and the Internet of Everything (V2X) communication.

[0008] The present invention provides a method for protecting privacy in an Internet of Vehicles (IoV) based on CNTR on an NTRU grid, which specifically includes the following steps:

[0009] S1, initialization settings, the trusted center configures system parameters;

[0010] S2. Vehicle registration: The vehicle is registered with the trusted center when it leaves the factory, and the current vehicle private key is generated;

[0011] S3. The drive test unit registers. The public key of the drive test unit uses the system public key broadcast by the trusted center, and the private key of the drive test unit uses the system private key.

[0012] S4, message signcryption, sign the message broadcast;

[0013] S5. Message decryption: After the road test unit obtains the signcrypted message sent by the vehicle, it uses the system private key to decrypt the signcryption.

[0014] As a preferred embodiment of the present invention, step S1 further includes:

[0015] S1.1. Input to the trusted center at the server layer: security parameters , number of ring members , then the trusted center determines the system parameters; the ring polynomial dimension , modulus , central binomial distribution , Gaussian parameters , and hash functions 、 、 ,in Refers to the integer modulus The polynomial ring of ; is a hash function that maps binary data to a ring, It is a hash function that maps polynomials on a ring to binary data. The polynomial in the system private key and The result of the product is mapped into binary data;

[0016] S1.2. Determine the parameters selected by the trusted center ,in is the independent variable of the polynomial in the ring, is the modulus The integer ring of ; by compact Gaussian sampling in Gaussian distribution Choose a polynomial with small coefficients As the system private key , where the polynomial with small coefficients Must be reversible, otherwise reselect a small coefficient polynomial , use polynomial inversion and polynomial multiplication to calculate the system public key ,in It will The result of the operation and the modulus Take the remainder, Is the system public key ;

[0017] S1.3, the system public key , hash function Packaged as system public parameters ) and broadcast it to all vehicles, keeping the system private key secret.

[0018] As a preferred embodiment of the present invention, step S2 further includes:

[0019] S2.1. The vehicle is registered with the trusted center when it leaves the factory. , to obtain a digital certificate, where It is the vehicle's factory ID. is the registration timestamp, As the vehicle public key;

[0020] S2.2. Generate the current vehicle private key: The vehicle obtains the system public parameters broadcast by the trusted center, and then the vehicle uses compact Gaussian sampling to generate the current vehicle private key in the Gaussian distribution. Select , by calculating Get satisfied of ,Will As the private key of the current vehicle, it is the serial number of the current vehicle, and These are two of the vehicle private keys of the current vehicle.

[0021] As a preferred embodiment of the present invention, step S4 also includes:

[0022] S4.1. When the vehicle sends a message When first obtaining the public keys of the 8 surrounding vehicles 、 、 、 、 、 、 、 Forming a dynamic loop 、 、 、 、 、 、 、 , obtain the drive test unit public key;

[0023] S4.2. Generate linkable tags : Message will be sent The geographic location of the vehicle and time windows Packed into time tags , the vehicle private key With time label Packaged into linkable tags ;

[0024] S4.3, encrypt the message, first of length News Split into multiple groups of 4-bit binary strings , making , then use the encoding function , , each binary string Coded to be scalable points on the grid ,in , is the scaling factor, let , is mapped to points on the grid A collection of

[0025] Then, the vehicle randomly selects a random vector by discrete Gaussian sampling , discrete Gaussian sampling randomly selects noise ,in , by calculating the blinding vector The random vector Blind, calculate signature component , calculate the ciphertext , using modular compression technology module to compress ciphertext ,in is the modular compression function, It is the public key used when the drive test unit is registered;

[0026] Finally, the dynamic ring , linkable tags , timestamp , blinded vector , signature component , compressed ciphertext Packed as a signcrypted message , and the signcrypted message broadcast.

[0027] As a preferred embodiment of the present invention, step S5 further includes:

[0028] S5.1. First, the road test unit receives the signcryption message broadcast by the vehicle , use the decompression technology module to decompress the compressed ciphertext Get ciphertext ; The ciphertext Modulus with part of the system private key The random vector is obtained by polynomial multiplication of , the ciphertext After eliminating the interference terms in Encoded messages on the lattice , which can be expanded by solving The nearest pair of vectors on the lattice encodes the message After decoding, the decoded message is obtained , where the decoding function is ;

[0029] S5.2, the road test unit receives the signcryption message sent by the vehicle After that, the signature is verified and the dynamic ring sent by the vehicle is , the road test unit obtains 8 vehicle public keys 、 、 、 、 、 、 、 , and then verify the difference between the blinded vector and the signature component of the 8 car public keys in turn , the serial number of the current vehicle ,like , is the allowable error, , the verification is successful and the message will be decoded Broadcast to other vehicles, otherwise return verification failure.

[0030] The beneficial effects of the present invention are as follows:

[0031] This invention utilizes NTRU lattice cryptography and ring signature technology to achieve quantum-safe protection for vehicle-to-everything (V2X) communications. Key features include resistance to quantum attacks, using a method based on the mathematically challenging "lattice shortest vector problem" to prevent quantum computers from quickly cracking it. Furthermore, algorithms optimized for automotive chipsets achieve emergency message processing times of less than 5 milliseconds.

[0032] 2. This invention, based on a dynamic ring construction mechanism, randomly selects fake identities from neighboring vehicles to form an 8-element obfuscation ring. Even if an attacker intercepts communication data, they cannot determine the true sender's identity through probabilistic analysis. The anonymity strength reaches Pr[identification success] ≤ 1 / 8, which is at least 4 times more effective than traditional solutions. The PolyEncode method achieves a fault-tolerant mapping of messages to polynomial rings. Combined with the NTRU-LWE encryption structure, this method guarantees a 99.98% message decryption success rate even in tunnel scenarios with a channel error rate as high as 0.35%. Furthermore, the hybrid-based NTT acceleration technology is deeply optimized. Adopting a 32 / 16 / 8-bit layered computing strategy tailored to the instruction set characteristics of automotive chipsets, this reduces the 768-dimensional polynomial multiplication cycle from 12,400 in traditional methods to 2,150. This reduces the signcryption operation to just 4.2ms on a Cortex-M4 @ 120MHz chip, fully meeting the ETSI standard's 5ms end-to-end latency requirement for connected vehicle emergency messages.

[0033] 3. In terms of security enhancement, the present invention innovatively implements a linkable tag mechanism and a quantum-resistant signature structure. Value tags ensure that the behavior of the same vehicle within a 5-minute time window is traceable while also protecting against Sybil attacks (the cost of forging an identity is ≥ 2^128 operations). Modular compression technology compresses the ciphertext size from 768 coefficients (1152 bytes) to 512 bits. Pre-calculating the NTT twiddle factors keeps the decompression latency within 0.8ms, reducing communication overhead by 62% compared to traditional ZKP schemes. To combat side-channel attacks, a constant-time sampling algorithm is employed to eliminate branch prediction vulnerabilities in polynomial multiplication and Gaussian sampling. Power analysis testing has verified that the risk of key parameter leakage is reduced to below 0.3nW / bit.

[0034] 4. The RSU node of this invention achieves a CPU utilization rate of only 72% at a peak load of 1200 req / s, and memory consumption is kept stable at less than 8.2KB, fully compatible with the hardware configuration of mainstream automotive ECUs. Through a dynamic mode switching mechanism (with a 20dB SNR threshold), the system automatically activates the efficient KXOR mode (388 bytes / message) on highways and switches to the noise-resistant Poly mode (636 bytes / message) in complex urban areas, achieving an optimal balance between communication efficiency and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] By referring to the following description in conjunction with the accompanying drawings, and with a more complete understanding of the present invention, other objects and results of the present invention will become more clear and easy to understand. In the accompanying drawings:

[0036] Figure 1 This is a network model diagram of the present invention;

[0037] Figure 2 It is a flow chart of system initialization of the present invention;

[0038] Figure 3 This is the RSU and vehicle registration flow chart of the present invention;

[0039] Figure 4 Flowchart of sending signcryption message for vehicle signcryption of the present invention;

[0040] Figure 5 This is the flow chart of the RSU decryption and verification message of the present invention;

[0041] Figure 6 This is the UML diagram of the present invention. DETAILED DESCRIPTION

[0042] See Figure 1-6 The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] The embodiment of the present invention provides a method for protecting privacy in an Internet of Vehicles (IoV) based on CNTR on an NTRU grid, which specifically includes the following steps:

[0044] S1. Initialization settings:

[0045] S1.1. Input to the Trusted Authority (TA) at the server layer: security parameters , number of ring members , then the trusted center (TA) determines the system parameters; the ring polynomial dimension , modulus , central binomial distribution , Gaussian parameters , and hash functions (Based on SHA3-512 construction), (Key Derivation Function), (HMAC-SHA256), where Refers to the integer modulus The polynomial ring of ; is a hash function that maps binary data to a ring, It is a hash function that maps polynomials on a ring to binary data. The polynomial in the system private key and The result of the product is mapped into binary data;

[0046] S1.2. Determine the parameters selected by the trusted center ,in is the independent variable of the polynomial in the ring, is the modulus The integer ring of ; by compact Gaussian sampling in Gaussian distribution Choose a polynomial with small coefficients As the system private key , where the polynomial with small coefficients Must be reversible, otherwise reselect a small coefficient polynomial , use polynomial inversion and polynomial multiplication to calculate the system public key ,in It will The result of the operation and the modulus Take the remainder, Is the system public key ;

[0047] S1.3, the system public key , hash function Packaged as system public parameters ) and broadcast it to all vehicles, keeping the system private key secret;

[0048] S2. Vehicle Registration:

[0049] S2.1. The vehicle is registered with the trusted center when it leaves the factory. , to obtain a digital certificate ( ),in It is the vehicle's factory ID. is the registration timestamp, As the vehicle public key;

[0050] S2.2. Generate the current vehicle private key: The vehicle obtains the system public parameters broadcast by the trusted center, and then the vehicle uses compact Gaussian sampling to generate the current vehicle private key in the Gaussian distribution. Select , by calculating Get satisfied of ,Will As the private key of the current vehicle, is the serial number of the current vehicle, and Two of the vehicle private keys of the current vehicle;

[0051] S3. Road Test Unit (RSU) registration:

[0052] The public key of the RSU uses the system public key broadcast by the trusted center , the private key of the drive test unit uses the system private key ;

[0053] S4. Message Signcryption:

[0054] S4.1. When the vehicle sends a message When first obtaining the public keys of the 8 surrounding vehicles 、 、 、 、 、 、 、 Forming a dynamic loop 、 、 、 、 、 、 、 , obtain the drive test unit public key;

[0055] S4.2. Generate linkable tags : Message will be sent The geographic location of the vehicle and time windows Packed into time tags , the vehicle private key With time label Packaged into linkable tags ;

[0056] S4.3, encrypt the message, first of length News Split into multiple groups of 4-bit binary strings , making , then use the encoding function , , each binary string Coded to be scalable grid( Grid points on the grid ,in , is the scaling factor, let , is mapped to points on the grid A collection of

[0057] Then, the vehicle randomly selects a random vector by discrete Gaussian sampling , discrete Gaussian sampling randomly selects noise ,in , by calculating the blinding vector The random vector Blind, calculate signature component , calculate the ciphertext , using modular compression technology module to compress ciphertext ,in is the modular compression function, It is the public key used when the drive test unit is registered;

[0058] Finally, the dynamic ring , linkable tags , timestamp , blinded vector , signature component , compressed ciphertext Packed as a signcrypted message , and the signcrypted message broadcast;

[0059] S5. Message decryption:

[0060] S5.1. First, the road test unit receives the signcryption message broadcast by the vehicle , use the decompression technology module to decompress the compressed ciphertext Get ciphertext ; The ciphertext Modulus with part of the system private key The random vector is obtained by polynomial multiplication of , the ciphertext After eliminating the interference terms in grid( Encoded message on the grid , which can be expanded by solving grid( The closest vector (CVP) on the lattice encodes the message After decoding, the decoded message is obtained , where the decoding function is ;

[0061] S5.2, the road test unit receives the signcryption message sent by the vehicle After that, the signature is verified and the dynamic ring sent by the vehicle is , the road test unit obtains 8 vehicle public keys 、 、 、 、 、 、 、 , and then verify the difference between the blinded vector and the signature component of the 8 car public keys in turn , the serial number of the current vehicle ,like , is the allowable error, , the verification is successful and the message will be decoded Broadcast to other vehicles, otherwise return verification failure.

[0062] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A privacy protection method for Internet of Vehicles based on CNTR on NTRU grid, characterized by: The following steps are involved: S1, initialization settings, the trusted center configures system parameters; S1.

1. Input to the trusted center of the server layer: security parameter λ = 12, number of ring members N ≤ 1000, and then the trusted center determines the system parameters: ring polynomial dimension n = 768, modulus q = 3457, central binomial distribution B3, Gaussian parameter σ = 3.24, and hash function H1: {0,1} * →R q 、H2:R q →{0,1} 256 、H3:R q ×R q →{0,1} 256 , where R q Refers to the polynomial ring of integer modulus q; H1 is the hash function that maps binary data to the ring, H2 is the hash function that maps the polynomial on the ring to binary data, and the hash function H3 maps the product of the polynomials f and g in the system private key to binary data; S1.

2. Determine the ring R through parameters selected by the trusted center q =Z q [x] / (x 768 -x 384 +1), where x is the independent variable of the polynomial in the ring, Z q is the integer ring of modulus q; by compact Gaussian sampling in Gaussian distribution (D Zn,σ ) selects small coefficient polynomials f and g as the system private key MSK = {f, g}, where the small coefficient polynomial f must be reversible. Otherwise, reselect small coefficient polynomials f and g, and use polynomial inversion and polynomial multiplication to calculate the system public key MPK = h = g·f -1 modq, where mod is g·f -1 The result of the operation is modulo q, h is the system public key MPK; S1.

3. Package the system public key MPK = h and the hash functions H1, H2, H3 into system public parameters params = (h, H1, H2, H3) and broadcast them to all vehicles, keeping the system private key secret. S2. Vehicle registration: The vehicle is registered with the trusted center when it leaves the factory, and the current vehicle private key is generated; S3. The drive test unit registers. The public key of the drive test unit uses the system public key broadcast by the trusted center, and the private key of the drive test unit uses the system private key. S4: Message signcryption, broadcast the signcrypted message C; S5. Message decryption: After the road test unit obtains the signcrypted message sent by the vehicle, it uses the system private key to decrypt the signcryption.

2. The method for protecting privacy in an Internet of Vehicles based on CNTR on the NTRU grid according to claim 1 is characterized in that: Step S2 also includes: S2.

1. The vehicle is registered with the trusted center when it leaves the factory. i =H1(VID i ||t) to obtain a digital certificate, where VID i is the vehicle factory ID, t is the registration timestamp, PID i As the vehicle public key; S2.

2. Generate the current vehicle private key: The vehicle obtains the system public parameters broadcast by the trusted center, and then the vehicle uses compact Gaussian sampling to generate the current vehicle private key in the Gaussian distribution D Zn,σ Select s1, calculate s2 = -s1·hmodq to obtain s2 that satisfies s1+s2·h≡0modq, and then SK i =(s1,s2) is the private key of the current vehicle, i is the serial number of the current vehicle, s1 and s2 are two of the vehicle private keys of the current vehicle.

3. The method for protecting privacy in an Internet of Vehicles based on CNTR on the NTRU grid according to claim 1 is characterized in that: Step S4 also includes: S4.

1. When a vehicle sends a message m, it first obtains the public keys PID1, PID2, PID3, PID4, PID5, PID6, PID7, and PID8 of the eight surrounding vehicles to form a dynamic loop U = (PID1, PID2, PID3, PID4, PID5, PID6, PID7, and PID8), and then obtains the public key of the drive test unit. S4.

2. Generate a linkable tag J: the geographic location geo and time window t of the vehicle that will send the message m window Packed into time tag event = H1(geo||t window ), the vehicle private key SK i =(s1,s2) and the time tag event are packaged into a linkable tag J=H2(s1||s2||event); S4.

3. To encrypt the message, first split the message m∈{0,1}l of length l into multiple groups of 4-bit binary strings k j ∈{0,1} 4 , so that k j =(k1,k2,…,k j ,…,k l / 4 ), and then use the encoding function PolyEncode(k)=V, V=(V1,V2,…,V l / 4 ), encode each binary string k into a grid point V = μ(k j hmod2), where j = 1, 2, ..., l / 4, μ is the scaling factor, and V is the grid point mapped to the E8 grid (V1, V2, ..., V l / 4 ) Then, the vehicle randomly selects a random vector by discrete Gaussian sampling Discrete Gaussian sampling randomly selects noise (e1, e2), where The random vector r is blinded by calculating the blinding vector y = r·h + e1modq, and the signature component z = r·PID is calculated. i +e2modq, calculate the ciphertext c=(r·h RSU +PolyEncode(m))modq, uses the modular compression technology module to compress the ciphertext c comp =Compress(c, bits=512), where Compress(c, bits=512) is the modular compression function, h RSU It is the public key used when the drive test unit is registered; Finally, the dynamic ring U, linkable label J, timestamp t, blinded vector y, signature component z, compressed ciphertext c comp Packaged into a signcrypted message C = {U, J, t, y, z, c comp }, and broadcast the signcrypted message C.

4. The method for protecting privacy in an Internet of Vehicles based on CNTR on the NTRU grid according to claim 1 is characterized in that: In step S5, it also includes: S5.

1. First, the road test unit receives the signcrypted message C broadcast by the vehicle and uses the decompression technology module to decompress the compressed ciphertext c. comp Obtain ciphertext c; perform a polynomial multiplication of the ciphertext c and a portion of the system private key modulo q to obtain a random vector r′ = c·fmodq. After eliminating interference terms in the ciphertext c, obtain an encoded message V′ = cr′·hmodq on the expandable E8 lattice. Decode the encoded message V′ by finding the nearest vector on the expandable E8 lattice to obtain a decoded message m′, where the decoding function is PolyDecode(V′). S5.

2. After receiving the signcryption message C sent by the vehicle, the road test unit verifies the signature. Through the dynamic loop U sent by the vehicle, the road test unit obtains the eight vehicle public keys PID1, PID2, PID3, PID4, PID5, PID6, PID7, and PID8. Then, the difference Δ between the blinding vector and the signature component is verified for the eight vehicle public keys in turn. i =zy·PID i modq, the current vehicle number i=1,2,·,8, if ‖Δ i ‖ ∞ ≤β, β is the allowed error, β<12, then the verification is successful and the decoded message m′ is broadcast to other vehicles, otherwise verification failure is returned.

Images