A certificateless signcryption method for vehicular ad hoc networks

Abstract

The certificateless signcryption method for vehicular ad hoc networks of the present invention includes: the KGC generates system parameters according to the security parameters input by the user; and generates a pseudonym of the vehicle and a partial private key of the vehicle according to the system parameters; the vehicle generates a complete private key of the vehicle and a public key of the vehicle by using a bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle and the system parameters, and uploads the pseudonym of the vehicle and the public key of the vehicle to the blockchain to generate a vehicle pseudonym public key table of the vehicle; the first vehicle obtains the public key of the second vehicle from the blockchain according to the pseudonym of the second vehicle, and the first vehicle uses a signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters to generate a signcrypted ciphertext, and sends the signcrypted ciphertext to the second vehicle; the second vehicle decrypts the signcrypted ciphertext through a decryption algorithm according to the signcrypted ciphertext and the system parameters to obtain a decrypted user message; and receives the valid decrypted user message to improve the security of the vehicular ad hoc network.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle networking security, and particularly relates to a certificateless signcryption method for vehicular ad hoc networks. Background Art

[0002] With the continuous development of the automotive industry and communication technology, the number of motor vehicles in use has been increasing year by year. The popularization of motor vehicles has brought great convenience to people's lives, but problems such as traffic safety, road congestion, and environmental pollution caused by fuel are becoming increasingly serious. To effectively reduce traffic accidents, alleviate road congestion, improve the driving experience, and reduce energy consumption, vehicular ad hoc networks have emerged. Currently, the core problem of vehicular ad hoc networks is how to ensure secure communication between vehicles and between vehicles and infrastructure. However, due to the high mobility of vehicle nodes, the wireless communication time between nodes is short, and the network topology changes rapidly. Attackers can easily eavesdrop on, modify, and replay messages through the open wireless transmission channel, bringing a series of problems to the communication security of vehicular ad hoc networks, the privacy protection of users, and driving safety. As a technology to ensure the reliability, integrity, and timeliness of messages during the communication process, security authentication is considered a key technology for ensuring the communication security of vehicular ad hoc networks by authenticating the vehicle identity and messages of the message sender.

[0003] Existing security authentication methods for vehicular ad hoc networks have low authentication efficiency and do not have the ability to be decentralized. For example, authentication based on public key infrastructure requires a KGC (Key Generation Center), and a large number of revocation lists increase the communication overhead; although the identity-based authentication scheme does not require a key generation center, there is a key escrow problem. Summary of the Invention

[0004] To solve the problems of low authentication efficiency, lack of decentralization ability, and key escrow in the security authentication of existing vehicular ad hoc networks, the present invention combines blockchain technology and a certificateless signcryption mechanism to provide a certificateless signcryption method for vehicular ad hoc networks, including:

[0005] S1: The KGC generates system parameters according to the security parameters input by the user and publishes the system parameters to the vehicles in the vehicular ad hoc network;

[0006] S2: The KGC obtains the real information of the vehicle and uses the system parameters to generate the pseudonym of the vehicle and the partial private key of the vehicle through the pseudonym generation algorithm and the partial private key generation algorithm, and sends the pseudonym of the vehicle and the partial private key of the vehicle to the vehicle through a secure channel;

[0007] S3: The vehicle generates the complete private key and public key of the vehicle by using the bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle, and the system parameters, and uploads the pseudonym of the vehicle and the public key of the vehicle to the blockchain to generate the vehicle pseudonym public key table of the vehicle;

[0008] S4: The first vehicle obtains the user message, determines the second vehicle that needs to receive the user message according to the user message, and obtains the public key of the second vehicle from the blockchain according to the pseudonym of the second vehicle;

[0009] S5: The first vehicle uses the signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters, generates the signcrypted ciphertext, and sends the signcrypted ciphertext to the second vehicle;

[0010] S6: The second vehicle decrypts the signcrypted ciphertext according to the signcrypted ciphertext and the system parameters through the decryption algorithm to obtain the decrypted user message, and judges whether the decrypted user message is valid through the system parameters; when the decrypted user message is valid, the second vehicle receives the decrypted user message.

[0011] The present invention has at least the following beneficial effects compared with the prior art:

[0012] Considering the limited computing and storage resources of in-vehicle terminal devices, the present invention adopts a certificateless signcryption mechanism, which not only avoids the problem of low authentication efficiency caused by traditional cryptography due to signing first and then encrypting, but also solves the problems of key escrow and certificate management, reduces the computing overhead. The blockchain is used to record the vehicle pseudonym public key table of registered vehicles. Vehicle nodes will synchronize the vehicle pseudonym public key table of registered vehicles in real time according to the blockchain, realizing the distributed storage and query of vehicle public key information, effectively preventing single point of failure and illegal users from tampering with the public key information of vehicles, improving the security of the public key. In the process of user message verification, the present invention can achieve message authentication without the online participation of the key generation center KGC, improving the authentication security of the vehicular ad hoc network. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flowchart of the present invention;

[0014] Figure 2 is a schematic flowchart of the basic process of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The technical solutions of the present invention will be clearly and detailedly described below in conjunction with the accompanying drawings of the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention and cannot be used to limit the scope of the present invention.

[0016] Please refer to Figure 1 , the present invention provides a certificateless signcryption method for a vehicular ad hoc network, including:

[0017] S1: The KGC generates system parameters according to the security parameters input by the user and publishes the system parameters to the vehicles in the vehicular ad hoc network. The vehicular ad hoc network includes: vehicles, a blockchain network, and a key generation center (KGC). The vehicles perform data interactions with the blockchain network and the key generation center (KGC) respectively.

[0018] Preferably, the KGC generating system parameters according to the security parameters input by the user includes:

[0019] S11: The KGC generates two cyclic additive groups \(G_1\) and \(G_2\) of order \(q\) by using the bilinear group generation algorithm according to the security parameters input by the user 1 and \(G_2\) 2 ; and obtains a cyclic multiplicative group \(G_T\) of order \(q\) through the bilinear mapping algorithm according to the cyclic additive groups \(G_1\) 1 and \(G_2\) 2 ;

[0020] S12: The KGC selects a random number \(s\) as the master key from and calculates the master public key \(P\) 2 through the master public key generation algorithm by using the master key \(s\) and the cyclic additive group \(G_1\) pub , where \(P\) pub = \(sW\), represents a finite field,

[0021] S13: The KGC calls two cryptographic Hash functions \(H_1\) 1 and \(H_2\) 2 , and generates system parameters through the system parameter generation algorithm based on the two cryptographic Hash functions \(H_1\) 1 and \(H_2\) 2 as well as the cyclic additive groups \(G_1\) 1 and \(G_2\) 2 ; The system parameters include: \(q\), \(P\), \(W\), \(G_1\) 1 , \(G_2\) 2 , \(G_T\) T , \(P_0\) pub , \(H_1\) 1 and \(H_2\) 2 ; \(P\) represents the generator of the cyclic additive group \(G_1\) 1 , \(q\) represents a large prime number, and \(W\) represents the generator of the cyclic additive group \(G_2\) 2 ;

[0022] Preferably, the cryptographic Hash functions \(H_1\) 1 and \(H_2\) 2 include:

[0023] H_1 1 : \(\{0,1\}\) * → \(G_1\)1

[0024] H 2 :G T →{0,1} π

[0025] Among them, H 1 :{0,1} * →G 1 represents the mapping of a set of bit strings of any length to points on the elliptic curve G 1 in, H 2 :G T →{0,1} π represents the mapping of points on the elliptic curve G T to a set of strings of length π bits.

[0026] S2: The KGC obtains the real information of the vehicle and uses the system parameters to generate the pseudonym of the vehicle and the partial private key of the vehicle through the pseudonym generation algorithm and the partial private key generation algorithm, and sends the pseudonym of the vehicle and the partial private key of the vehicle to the vehicle through a secure channel.

[0027] Preferably, the generating the pseudonym of the vehicle and the partial private key of the vehicle by using the system parameters through the pseudonym generation algorithm and the partial private key generation algorithm includes:

[0028] S21: The KGC calculates the pseudonym of the vehicle according to the real information of the vehicle and the system parameter H 1 through the pseudonym generation algorithm;

[0029] Preferably, the pseudonym of the vehicle includes:

[0030]

[0031] Among them, represents the real information of vehicle V i and represents the pseudonym of vehicle V i .

[0032] S22: The KGC calculates the partial private key of the vehicle according to the pseudonym of the vehicle and the system parameter s through the partial private key generation algorithm;

[0033] Preferably, the partial private key of the vehicle includes:

[0034]

[0035] Among them, represents the partial private key of the vehicle, represents the pseudonym of vehicle V i .

[0036] S3: The vehicle generates the complete private key and the public key of the vehicle by using the bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle, and the system parameters, and uploads the pseudonym of the vehicle and the public key of the vehicle to the blockchain to generate the vehicle pseudonym public key table of the vehicle.

[0037] The vehicle generates the complete private key and the public key of the vehicle by using the bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle, and the system parameters, including:

[0038] S31: The vehicle constructs a first equation by using the bilinear mapping algorithm according to the pseudonym of the vehicle and the partial private key of the vehicle with the system parameters. When the first equation holds, the vehicle receives the pseudonym of the vehicle and the partial private key of the vehicle;

[0039] Preferably, the first equation includes:

[0040]

[0041] Among them, represents the bilinear mapping function, and W represents the generator of the cyclic additive group G 2 of.

[0042] S32: The vehicle selects a random number from and calculates the complete private key of the vehicle by using the random number and the partial private key of the vehicle through the complete private key generation algorithm;

[0043] Preferably, the complete private key of the vehicle includes:

[0044]

[0045] Among them, represents the complete private key of vehicle V i , represents the partial private key of vehicle V i , represents a random number selected from.

[0046] S33: The vehicle calculates the public key of the vehicle by using the bilinear mapping algorithm according to the complete private key of the vehicle and the system parameter W.

[0047] Preferably, the public key of the vehicle includes:

[0048]

[0049] Among them, represents the public key of vehicle V i , W represents the generator of the cyclic additive group G 2 of, Represents a bilinear mapping function, Represents vehicle V i 's complete private key.

[0050] Please refer to Figure 2 , the vehicle pseudonym public key table of the said vehicle is as follows:

[0051] Vehicle pseudonym public key table

[0052]

[0053] Among them, and respectively represent the pseudonyms of vehicles in the vehicular ad hoc network, represents the public key of vehicle V i , represents the pseudonym of vehicle V j .

[0054] S4: The first vehicle obtains the user message, determines the second vehicle that needs to receive the user message according to the user message, and obtains the public key of the second vehicle from the blockchain according to the pseudonym of the second vehicle. Both the first vehicle and the second vehicle are vehicles in the vehicular ad hoc network. The first vehicle is the user information sender, and the second vehicle is the user information receiver. Among them, the user message includes: information input by people to the vehicle, security messages sent by the vehicular network itself, messages sent by other devices to the first vehicle, etc.

[0055] S5: The first vehicle uses the signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters, generates a signcrypted ciphertext, and sends the signcrypted ciphertext to the second vehicle.

[0056] Preferably, the first vehicle uses the signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters, and generating a signcrypted ciphertext includes:

[0057] S51: The first vehicle calls the system parameter H according to the pseudonym of the first vehicle, the pseudonym of the second vehicle, and the user message 1 to calculate the first hash value;

[0058] Preferably, the first hash value includes:

[0059]

[0060] Among them, h 1 represents the first hash value, represents the pseudonym of the first vehicle V i , represents the pseudonym of the second vehicle V j , and m i represents the user message.

[0061] S52: The first vehicle randomly selects a random number r from i , and calculates the first ciphertext using the bilinear mapping algorithm based on the complete private key of the first vehicle V i , the system parameter W, and the first hash value;

[0062] Preferably, the first ciphertext includes:

[0063]

[0064] where σ 1,i represents the first ciphertext, represents the bilinear mapping function, represents the complete private key of the first vehicle V i , W represents the generator of the cyclic additive group G 2 ;

[0065] S53: The first vehicle calculates the second hash value using the public key of the second vehicle and the random number r i and the system parameter H 2 , and calculates the second ciphertext by performing an exclusive OR operation on the second hash value and the user message;

[0066] Preferably, the second ciphertext includes:

[0067]

[0068]

[0069] where σ 2,i represents the second ciphertext, h 2 represents the second hash value, m i represents the user message, represents the public key of the second vehicle V j ;

[0070] S54: The first vehicle multiplies the random number r i and the system parameter W to obtain the third ciphertext, and generates the signed ciphertext based on the first ciphertext, the second ciphertext, and the third ciphertext.

[0071] Preferably, the signed ciphertext includes:

[0072] σ i =(R i ,σ 1,i ,σ 2,i )

[0073] R i =r i W

[0074] where Ri Represents the third ciphertext, σ i Represents the signed ciphertext, σ 2,i Represents the second ciphertext, σ 1,i Represents the first ciphertext.

[0075] S6: The second vehicle decrypts the signed ciphertext through a decryption algorithm based on the signed ciphertext and system parameters to obtain the decrypted user message, and determines whether the decrypted user message is valid through the system parameters; when the decrypted user message is valid, the second vehicle receives the decrypted user message.

[0076] Preferably, the second vehicle decrypting the signed ciphertext through a decryption algorithm based on the signed ciphertext and system parameters to obtain the decrypted user message includes:

[0077] S61: The second vehicle calculates a mapping value by a bilinear mapping algorithm using the complete private key of the second vehicle and the third ciphertext, and calls the system parameter H based on the mapping value 2 to calculate the third hash value;

[0078] Preferably, the third hash value includes:

[0079]

[0080] where, h 3 represents the third hash value, R i represents the third ciphertext, represents the complete private key of the second vehicle V j and, represents the bilinear mapping function.

[0081] S62: The second vehicle performs an exclusive OR operation on the third hash value and the second ciphertext to calculate and obtain the decrypted user message.

[0082] Preferably, the decrypted user message includes:

[0083]

[0084] where, represents the decrypted user message, h 3 represents the third hash value, σ 2,i represents the second ciphertext.

[0085] Preferably, determining whether the decrypted user message is valid through the system parameters includes:

[0086] S621: When the second vehicle receives only one decrypted user message; the second vehicle constructs a second equation through a bilinear mapping algorithm based on system parameters, the first ciphertext, the third ciphertext, the pseudonym of the first vehicle, the public key of the first vehicle, the pseudonym of the second vehicle, and the decrypted user message; and determines whether the decrypted user message is valid according to whether the second equation holds. When the second equation holds, the decrypted user message is valid; when the second equation does not hold, the decrypted user message is invalid and an error message is returned;

[0087] Preferably, the second equation includes:

[0088]

[0089] where σ 1,i represents the first ciphertext, represents the public key of V i of the first vehicle, represents the pseudonym of the first vehicle, represents the pseudonym of the second vehicle, represents the user message of the first vehicle Vi, represents the bilinear mapping function, R i represents the third ciphertext.

[0090] S622: When the second vehicle receives multiple decrypted user messages at the same time; the second vehicle constructs a third equation through a bilinear mapping algorithm based on the decrypted user message, system parameter H 1 , the first ciphertext, the public key of the first vehicle, the third ciphertext, and the pseudonym of the first vehicle; and determines whether the decrypted user message is valid according to whether the third equation holds.

[0091] Preferably, the third equation includes:

[0092]

[0093] where, where σ 1,i represents the first ciphertext, represents the public key of vehicle V i of, represents the bilinear mapping function, R i represents the third ciphertext, represents the decrypted user message of the first vehicle V i , represents the pseudonym of the first vehicle V i , represents the second vehicle Vj 's pseudonym, and n represents the number of the first vehicles.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Without departing from the spirit and essence of the method of the present invention, those skilled in the art can make various corresponding changes according to the method of the present invention, and these all fall within the scope protected by the claims of the method of the present invention.

Claims

1. A certificateless signcryption method for vehicular ad hoc networks, characterized in that, it includes: S1: The KGC generates system parameters according to the security parameters input by the user and publishes the system parameters to the vehicles in the vehicular ad hoc network; The KGC generating system parameters according to the security parameters input by the user includes: S11: The KGC generates two cyclic additive groups \(G\) and \(G\) of order \(q\) using the bilinear group generation algorithm based on the security parameters input by the user. And according to the cyclic additive groups \(G\) and \(G\), the cyclic multiplicative group \(G\) of order \(q\) is obtained through the bilinear mapping algorithm. 1 and \(G\) 2 ; and according to the cyclic additive group \(G\) 1 and \(G\) 2 a cyclic multiplicative group \(G\) of order \(q\) is obtained through the bilinear mapping algorithm T ; S12: KGC selects a random number S from as the master key, and uses the master key S and the cyclic additive group G 2 to calculate the master public key P through the master public key generation algorithm pub , where represents a finite field S13: KGC calls two cryptographic Hash functions H 1 and H 2 , and generates system parameters based on the two cryptographic Hash functions H 1 and H 2 as well as the cyclic additive group G 1 and G 2 through the system parameter generation algorithm; wherein, the system parameters include: q, P, W, G 1 , G 2 , G T , P pub , H 1 and H 2 ; P represents the generator of the cyclic additive group G 1 , q represents a large prime number, and W represents the generator of the cyclic additive group G 2 ; S2: The KGC obtains the real information of the vehicle and uses the system parameters to generate the pseudonym of the vehicle and the partial private key of the vehicle through the pseudonym generation algorithm and the partial private key generation algorithm, and sends the pseudonym of the vehicle and the partial private key of the vehicle to the vehicle through a secure channel; S3: The vehicle generates the complete private key of the vehicle and the public key of the vehicle by using the bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle and the system parameters, and uploads the pseudonym of the vehicle and the public key of the vehicle to the blockchain to generate the vehicle pseudonym public key table of the vehicle; S4: The first vehicle obtains the user message, determines the second vehicle that needs to receive the user message according to the user message, and obtains the public key of the second vehicle from the blockchain according to the pseudonym of the second vehicle; S5: The first vehicle uses the signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters, generates the signcrypted ciphertext, and sends the signcrypted ciphertext to the second vehicle; S6: The second vehicle decrypts the signcrypted ciphertext according to the signcrypted ciphertext and the system parameters through the decryption algorithm to obtain the decrypted user message, and judges whether the decrypted user message is valid through the system parameters; when the decrypted user message is valid, the second vehicle receives the decrypted user message.

2. The certificateless signcryption method for vehicular ad hoc networks according to claim 1, characterized in that, the generating the pseudonym of the vehicle and the partial private key of the vehicle by using the system parameters through the pseudonym generation algorithm and the partial private key generation algorithm includes: S21: The KGC calculates the pseudonym of the vehicle based on the real information of the vehicle and the system parameter H 1 through the pseudonym generation algorithm; S22: The KGC calculates the partial private key of the vehicle through the partial private key generation algorithm according to the pseudonym of the vehicle and the system parameter s.

3. The certificateless signcryption method for vehicular ad hoc networks according to claim 1, characterized in that, the vehicle generating the complete private key of the vehicle and the public key of the vehicle by using the bilinear mapping algorithm according to the pseudonym of the vehicle, the partial private key of the vehicle and the system parameters includes: S31: The vehicle constructs a first equation by using the bilinear mapping algorithm according to the pseudonym of the vehicle and the partial private key of the vehicle with the system parameters. When the first equation holds, the vehicle receives the pseudonym of the vehicle and the partial private key of the vehicle; S32: Vehicle from Choose a random number from And using random numbers The vehicle's complete private key is calculated using a complete private key generation algorithm using the vehicle's partial private key; S33: The vehicle calculates the public key of the vehicle by using the bilinear mapping algorithm according to the complete private key of the vehicle and the system parameter W.

4. The certificateless signcryption method for vehicular ad hoc networks according to claim 1, characterized in that, the first vehicle using the signcryption algorithm to signcrypt the user message according to the public key of the second vehicle and the system parameters, generating the signcrypted ciphertext includes: S51: The first vehicle calls the system parameter H based on the pseudonym of the first vehicle, the pseudonym of the second vehicle, and the user message 1 Calculate the first hash value; S52: The first vehicle randomly selects a random number r from and calculates a first ciphertext using a bilinear mapping algorithm based on the complete private key of the first vehicle, the system parameter W, and the first hash value; i ​ S53: The first vehicle calculates a second hash value based on the public key of the second vehicle and a random number r i using the system parameter H 2 and calculates a second ciphertext by performing an exclusive OR operation on the second hash value and the user message; S54: The first vehicle multiplies the random number r i by the system parameter W to obtain a third ciphertext, and generates a signature ciphertext based on the first ciphertext, the second ciphertext, and the third ciphertext.

5. The certificateless signcryption method for vehicular ad hoc networks according to claim 1, characterized in that, the second vehicle decrypting the signcrypted ciphertext according to the signcrypted ciphertext and the system parameters through the decryption algorithm to obtain the decrypted user message includes: S61: The second vehicle calculates a mapping value for the complete private key of the second vehicle and the third ciphertext through a bilinear mapping algorithm, and calls the system parameter H according to the mapping value 2 Calculate the third hash value; S62: The second vehicle performs an exclusive OR operation on the third hash value and the second ciphertext to calculate the decrypted user message.

6. The certificateless signcryption method for vehicular ad hoc networks according to claim 1 or 5, characterized in that, the determination of the validity of the decrypted user message by the system parameters includes: S621: When the second vehicle only receives one decrypted user message; the second vehicle constructs a second equation through the bilinear mapping algorithm according to the system parameters, the first ciphertext, the third ciphertext, the pseudonym of the first vehicle, the public key of the first vehicle, the pseudonym of the second vehicle and the decrypted user message; and determines whether the decrypted user message is valid according to whether the second equation holds; S622: When the second vehicle receives multiple decrypted user messages simultaneously; the second vehicle constructs a third equation based on the decrypted user messages, the system parameter H 1 , the first ciphertext, the public key of the first vehicle, the third ciphertext, and the pseudonym of the first vehicle through a bilinear mapping algorithm; and determines whether the decrypted user message is valid according to whether the third equation holds.

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