CN109802956B

CN109802956B - Anonymous vehicle-mounted network authentication system and method based on ring signature and vehicle communication platform

Info

Publication number: CN109802956B
Application number: CN201910000915.5A
Authority: CN
Inventors: 赖成喆; 胡天伟; 王文娟; 郭文龙; 郑东
Original assignee: Xian University of Posts and Telecommunications
Current assignee: Xian University of Posts and Telecommunications
Priority date: 2019-01-02
Filing date: 2019-01-02
Publication date: 2021-09-10
Anticipated expiration: 2039-01-02
Also published as: CN109802956A

Abstract

The invention belongs to the technical field of vehicle communication security, and discloses a ring signature-based vehicle network anonymous authentication system and method, and a vehicle communication platform; a trust institution and a vehicle with an OBU are registered to generate a partial private key; Vehicles register and preload public system parameters and corresponding public and private keys before joining the in-vehicle ad hoc network; when the vehicle is driving on the road, it passes security authentication and periodically broadcasts relevant status information; when it is found that the signer anonymously discloses false information Or its destructive behavior when the trusted agency reveals the true identity of the sender. The invention combines a certificateless public key cryptosystem with a ring signature to form a certificateless ring signature, which satisfies anonymity and unforgeability, and at the same time satisfies security authentication; additional relevant information forms a traceable algorithm to effectively solve the problem of the signer's anonymous disclosure of false messages or other In the event of sabotage, identity tracking and revocation are performed based on received messages.

Description

Anonymous vehicle-mounted network authentication system and method based on ring signature and vehicle communication platform

Technical Field

The invention belongs to the technical field of vehicle communication safety, and particularly relates to a vehicle-mounted network anonymous authentication system and method based on a ring signature and a vehicle communication platform.

Background

Currently, the current state of the art commonly used in the industry is such that: in order to reduce traffic accidents and improve traffic conditions, and provide corresponding network services for users, VANET (Vehicle-mounted network) is gradually emerging, which is a structural network that integrates a hybrid system of direct interconnection between vehicles, indirect interconnection between vehicles, and interconnection between vehicles and roadside fixed facilities, and can realize multi-hop wireless communication between vehicles (V2V) and vehicles (V2 to Infrastructure, V2I), and provide various security applications (such as accident warning, traffic management) and non-security applications (such as road condition indication, Internet access, and multimedia data communication between vehicles) for vehicles. In a VANET environment, vehicles can broadcast information such as road conditions to other vehicles without passing through a central server, and the vehicles can timely know the conditions of traffic accidents ahead through information interaction among the vehicles, so that the safety of roads is ensured; the traffic efficiency can be improved by the information interaction between the vehicles and roadside infrastructure and between the vehicles; high-speed connection with the Internet is established through roadside infrastructure, vehicles acquire various information such as traffic condition inquiry, service and the like, and enjoy multimedia services such as automobile conferences, online entertainment and the like through the Internet. One of the key issues in designing and deploying VANET is secure anonymous authentication between entities. On the one hand, it is desirable that messages authenticated during entity communication be sent by a reliable vehicle (sender) rather than a malicious or counterfeit vehicle; on the other hand, senders are reluctant to reveal identity or location information during authentication. Aiming at the privacy protection problem, the prior art provides a group signature-based vehicle networking privacy protection authentication scheme which can meet the requirements of anonymity and traceability, but needs the assistance of an RSU and the storage problem of a processing certificate; some schemes adopt a conditional ring signature method, and the second prior art provides a privacy protection communication scheme adopting a conditional anonymous ring signature in the Internet of vehicles, so that a group manager does not need to participate, but the storage and revocation problems of certificates exist; the third prior art provides an anonymous communication framework in a pseudonymous-based car networking environment, which includes several processes of pseudonym generation, pseudonym distribution, pseudonym regeneration and the like, and uses a distributed optimization algorithm to change pseudonyms, but a pseudonym method is adopted to continuously change pseudonyms, and the situation that the scheme is invalid due to the fact that the pseudonyms are modified in an improper time period or position is provided. Meanwhile, the fourth prior art provides a certificate-based anonymous authentication scheme for the Internet of vehicles, which can meet conditional identity tracking and has higher calculation efficiency, but the problems of certificate distribution, revocation and storage of a large number of certificates exist by adopting the method; the fifth prior art provides a threshold anonymous authentication protocol for the VANET, and the goal of conditional privacy and traceability is achieved by adopting a threshold group signature mode, but the group signature mode requires the participation of a group manager in the authentication process, which may result in an excessive authority. Therefore, in the existing anonymous authentication scheme of the vehicle-mounted network, when the requirements of anonymity and unforgeability are usually met, the requirement that the identity needs to be tracked when a receiver forges a message cannot be met; some of the vehicles meet basic safety requirements but cannot meet the requirement that the vehicle moves at any time and spontaneously forms a ring at any time in a vehicle-mounted network environment; even if the identity-based ring signature scheme is adopted, the problem of key escrow can be caused, so that a trusted third party can know the private key of each member, the dishonest third party can forge the signature of any member, and the safety is reduced. Therefore, the existing method cannot simultaneously meet the target requirements of spontaneity, high efficiency, anonymity, unforgeability and traceability.

In summary, the problems of the prior art are as follows: in the existing anonymous authentication scheme of the vehicle-mounted network, when the requirements of anonymity and unforgeability are usually met, the requirement that the identity needs to be tracked when a receiver forges a message cannot be met; some of the vehicles meet basic safety requirements but cannot meet the requirement that the vehicle moves at any time and spontaneously forms a ring at any time in a vehicle-mounted network environment; even the adoption of the identity-based ring signature scheme can cause the problem of key escrow, so that a trusted third party can know the private key of each member, the dishonest third party can forge the signature of any member, and the safety is reduced. Meanwhile, the target requirements of spontaneity, high efficiency, anonymity, unforgeability and traceability cannot be met at the same time.

The difficulty and significance for solving the technical problems are as follows: although many benefits may be brought by deploying VANET, security issues, such as anonymous authentication, must be well addressed before such application scenarios can be implemented. VANET encounters the greatest challenge in maintaining a reasonable balance between security and privacy. First, it is required that such information is reliable. Otherwise, unreliable messages may jeopardize the advantages of VANET. For example, modification and replay attacks on previously propagated messages using them may be fatal to some users. Meanwhile, privacy is another key issue for VANET. Otherwise, if the whereabouts and driving patterns of the car can be tracked, the driver's preference can be inferred. If the message broadcast in VANETS is unauthenticated, the driver cannot estimate traffic conditions from the received message, and an adversary can forge false information to mislead other drivers, or track the location of the intended vehicle. On the one hand, we expect the message to be verified by a trusted sender, not a malicious or fake vehicle. On the other hand, during authentication, the sender is reluctant to reveal its identity or location information. If the VANET is fully utilized on the basis of considering safety and privacy, the mutual cooperation of people, vehicles and roads can be realized, and various information such as real-time road conditions and the like can be published accurately and efficiently in real time. The traffic load is reduced by using the existing traffic facilities, and the traffic operation efficiency is improved on the basis of ensuring the traffic safety.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a vehicle network anonymous authentication system and method based on a ring signature and a vehicle communication platform.

The invention is realized in such a way, and the vehicular network anonymous authentication method based on the ring signature is characterized by comprising the following steps:

firstly, registering and registering a trust authority TA and a vehicle with an OBU to generate a part of private keys; the method comprises the steps that a vehicle of a vehicle-mounted communication unit OBU registers and preloads public system parameters and corresponding public and private keys before joining a vehicle-mounted self-organizing network;

secondly, when the vehicle runs on the road, the vehicle passes the safety certification and broadcasts relevant state information periodically; upon discovering that the signer anonymously divulges false messages or their act of destruction, the trust authority reveals the true identity of the sender.

Further, the first step specifically includes:

(1) an initialization stage: setting system parameters for each vehicle OBU, knowing a security parameter Z, and outputting by a trust authorityA large prime number q, G₁For cyclic addition groups, G₂Is a cyclic multiplicative group; p and Q are G₁A generator of (2); trust authority selection of master private key

Wherein S is kept secret and the master public key P is calculated_pubSP, wherein e: G₁×G₁→G₂For bilinear pairwise mapping, the 3 hash functions are respectively H₁:{0,1}^*→G₁，

After the initialization stage is completed, the trust authority discloses system parameters;

(2) vehicles with OBUs require preloaded key pairs, including private key pairs

Generating and user public key pairs

Generating; wherein the trust authority secretly stores the tag { Y_i,ID_iDisplaying corresponding vehicle identity ID_iAnd the public key Y_iUsing the label { Y ] in the tracking algorithm_i,ID_iThe relationship of (1) to trace the true identity of the malicious vehicle;

(3) for each vehicle in the vehicle network, generating a signature on the message m before sending the message; privacy protection is required for each type of vehicle, one vehicle mu_sWanting to propagate messages in a group, L ═ Y₁,Y₂,…Y_n) Is a vehicle mu_sSet of collected public keys, ω ═ ID₁,ID₂,…ID_nThe corresponding identity set of the vehicle is collected by the public key set mu_sTemporarily collected and stored; vehicle forming a ring mu ═ mu₁,μ₂,…μ_nForming a signature by executing a message signature algorithm and an identity tracking algorithm and sending the signature;

(4) the receiver is connectedAfter receiving the signature, the public key set L ═ Y of the known n signers₁,Y₂,…Y_n) Wherein r is_i＝H₂(m||ω||T,R_i,Y_i)，κ_i＝H₃(m||r_i||ω||T,K_i,Y_i) (ii) a It is checked whether the following equation holds.

If so, accepting the signature and considering the message to be from a reliable ring formed by the vehicle, otherwise rejecting the signature;

(5) when the receiver discovers that the signer anonymously leaks false messages or other destructive behaviors, or finds that someone in the area tries to falsify the sent information and destroy the communication safety, a temporary ring formed by the vehicle group is mu-mu₁,μ₂,…μ_nFind out the real signer mu_sTracking the vehicle and recalling the key; the receiver applies arbitration to the trust authority, the trust authority verifies the validity of the signature, and the true signer mu can be traced through one-time interaction with all members in the ring_s。

Further, the vehicle with the OBU needs to generate a public and private key pair as required as follows:

(1) given vehicle identity ID_iTrusted authority TA calculation

And will be

Sending the data to the vehicle;

(2) vehicle pass check equation

Whether the verification is established or not; if true, the vehicle selects a secret value

And calculates the public key Y_i＝x_iP；

(3) Vehicle preload private key pair

Public key pair

And broadcast in a formed temporary ring

Further, a vehicle mu with an OBU_sThe message can be sent only by forming a signature in the message sending process, and the signature forming process is as follows:

(1) randomly selecting a secret value

Where (i ═ 1,2 …, n), T is calculated_i＝t_iP，PK_i＝t_ix_iP，

(2) Selection of R_i,K_i∈G₁(i-1, 2 …, n \ s), calculating r_i＝H₂(m||ω||T,R_i,Y_i) Where i is 1,2, … s-1, s +1, …, n, calculating κ_i＝H₃(m||r_i||ω||T,K_i,Y_i) Wherein i is 1,2, … s-1, s +1, …, n;

(3) selecting a secret value

Computing

r_s＝H₂(m||ω||T,R_s,Y_s)，κ_s＝H₃(m||r_s||ω||T,K_s,Y_s)；

(4) Computing

(5) Output signed message σ ═ (R)₁,R₂,…R_n,K₁,K₂,…K_n,V,PK_iT, ω) and broadcasts the signed message in the ring formed by the vehicles.

Further, in the vehicle tracking process, the interaction process of the trust authority and the vehicle is carried out as follows:

(1) trust authority based on PK in output signature message sigma_iCollecting T to corresponding vehicle ring members_iValue, i.e.

(2) Trust authorities collect all T together_iAfter the value, by judging e (PK)_i,P)＝e(T_i,Y_i) Verification T_iThe effectiveness of (c). If T_iIf not, the corresponding ring member is considered to be a dishonest signer, if T_iIf the result is valid, the following steps are continued;

(3) if T_iValid, then calculate

By verifying the equation e (T, P) to e (U, Y)_i) If true, find the true signer mu_sIs the public key of (Y)_sAnd then through the label { Y_i,ID_iMu. tracing to the real signer_sAnd recalls the key.

Another object of the present invention is to provide a ring signature based vehicle-mounted network anonymous authentication system for performing the ring signature based vehicle-mounted network anonymous authentication method, the ring signature based vehicle-mounted network anonymous authentication system including:

a trust authority TA for registering with a vehicle with an OBU and assisting in generating a part of private keys;

the vehicle of the vehicle-mounted communication unit OBU is used for registering and preloading public system parameters and corresponding public and private keys before joining the vehicle-mounted self-organizing network; when the vehicle runs on the road, the relevant state information is periodically broadcast through safety certification; the trust authority reveals the true identity of the sender when the signer is found to anonymously reveal false messages or other corrupted behavior.

The invention further aims to provide a vehicle communication platform applying the ring signature-based anonymous authentication method for the vehicle-mounted network.

In summary, the advantages and positive effects of the invention are: the method is characterized in that the method depends on a vehicle with an OBU (on-board unit) and a trust authority TA (trust authority), safety certification is carried out in the communication process based on a certificate-free ring signature algorithm, related information is added to form a traceable algorithm, and the identity of a signer is traced according to effective information in the vehicle tracing stage. The invention is used for realizing the communication safety of vehicles in the VANET and simultaneously meeting the spontaneity and the traceability. The vehicle which communicates in a ring signature mode under the VANET environment can form a ring spontaneously and transmit information such as road conditions, traffic and the like in the driving process, a corresponding manager is not required to be appointed, and the device is simplified without depending on RSU (road side infrastructure); meanwhile, the certificateless mode is adopted to effectively solve the problems of key escrow and over-large authority of a trust authority TA; the certificateless ring signature formed by combining the certificateless ring signature and the ring signature meets the anonymity and the unforgeability, and meets the safety certification at the same time; the method has the advantages that the traceable algorithm formed by adding the related information effectively solves the problem that the identity is traced and cancelled according to the received message when the signer anonymously leaks false messages or other destructive behaviors; meanwhile, the method needs a small amount of bilinear pairings for calculation, is simple and practical and has a popularization effect as can be obtained through comparison in the table 1.

TABLE 1

The most expensive operation of the scheme in the invention is two stages of signature and verification in certificateless ring signature, most ring signature schemes applied in various environments need a large amount of bilinear pairings in the signature stage and the verification stage, but the bilinear pairings are more than the bilinear pairingsHe is more computationally expensive to operate. Representing a bilinear pair operation by PO, T_PORepresenting a scalar multiplication operation based on bilinear pairs, T_ERepresenting a scalar multiplication operation based on elliptic curves, T_NRepresenting a modulo exponential operation. Their execution efficiency is T from high to low under the same scale_E＞T_N＞T_PO>And PO. Since the hash function operation is relatively time-consuming, it is ignored here. Table 1 lists the conditional ring signature scheme proposed by the present invention and an efficient, multi-layered VANET secure communication protocol [1]Certificateless threshold ring signature technical document [2 ]]Ring signature technical document proposed for attribute-based anonymous authentication in trusted cloud computing [3]An efficiency comparison is made because these schemes are based on the ring signature scheme. And only when the anonymity of the signer needs to be revoked, the cooperation of the TA and other ring members is needed, and the TA and other ring members only need to perform interaction once to determine the real signer. This happens infrequently and therefore has little impact on the efficiency of the ring signature. The analysis mainly makes an efficiency comparison from the signature phase and the verification phase. From the comparison of the efficiency in table 1, it can be seen that the present invention uses an elliptic curve scalar multiplication operation with short calculation time in the signature stage, compared with the document [2 ]]Bilinear pairing operation is obviously not available, and the efficiency of the signature stage is obviously higher than that of the document [2 ]](ii) a Bilinear pairwise operation less than scheme [1 ] in verification phase]And document [3 ]]Therefore, the verification phase efficiency of the present invention is significantly higher than scheme [1 ]]And document [3]. From the total execution consumption of signature and verification, it is obvious that the bilinear pairing operation of the invention is less than that of the scheme [1 ]]And document [2 ]]And document [3]I.e. the overall execution efficiency is relatively higher than in scheme [1 ]]And document [2 ]]And document [3]The ring signature scheme of (1).

Drawings

Fig. 1 is a schematic structural diagram of a ring signature-based anonymous authentication system of a vehicle network according to an embodiment of the present invention;

in the figure: 1. a trust authority TA; 2. vehicle of on-board communication unit OBU.

Fig. 2 is a flowchart of a ring signature-based anonymous authentication method for a vehicle-mounted network according to an embodiment of the present invention.

Fig. 3 is a flowchart illustrating a communication scheme in a traveling process of a vehicle in a VANET environment according to an embodiment of the present invention.

Fig. 4 is a flowchart of generating a public-private key in a vehicle information preloading process according to an embodiment of the present invention.

Fig. 5 is a flowchart of tracking the identity of a real signer during a vehicle identity tracking stage according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a vehicle-mounted network anonymous authentication system and method based on a ring signature by using a certificateless ring signature and a tracking algorithm, which can ensure the anonymity and the unforgeability in the vehicle communication process, simultaneously adopts a certificateless mode to efficiently solve the problem of key escrow, forms the tracking algorithm by adding some related information in the ring signature, and tracks the real identity of a signer by the cooperation of a trusted third party and all members in the ring if necessary, thereby effectively solving the problem that the identity of the signer cannot be tracked.

The following detailed description of the principles of the invention is provided in connection with the accompanying drawings.

As shown in fig. 1, the ring signature-based anonymous authentication system for a vehicle-mounted network according to an embodiment of the present invention includes:

trust authority TA 1; for registering with a vehicle with an OBU and assisting in generating a partial private key;

a vehicle 2 of the on-board communication unit OBU for registering and preloading public system parameters and corresponding public and private keys before joining a VANET (on-board ad hoc network); when the vehicle runs on a road, the road environment is improved and the traffic safety is ensured through safety certification and periodic broadcasting of relevant state information; upon discovering that the signer anonymously divulges false messages or some other disruptive behavior, trust authority TA1 reveals the true identity of the sender.

As shown in fig. 2, the ring signature-based anonymous authentication method for a vehicle-mounted network according to the embodiment of the present invention includes the following steps:

s201: trust authority TA, and vehicle registration with OBU, and help generate part of the private key; the vehicle of the vehicle-mounted communication unit OBU registers and preloads public system parameters and corresponding public and private keys before joining a VANET (vehicle-mounted ad hoc network);

s202: when the vehicle runs on a road, the road environment is improved and the traffic safety is ensured through safety certification and periodic broadcasting of relevant state information; the trust authority TA reveals the true identity of the sender when the signer is found to anonymously reveal false messages or some other disruptive behavior.

The application of the principles of the present invention will now be described in further detail with reference to the accompanying drawings.

First, the mathematical theory and technical terminology applied by the invention are explained:

1. bilinear pairings

Bilinear pairings are very important concepts in cryptosystems and can be constructed by using Weil paring or Tate paring on elliptic curves. The basic idea is as follows: let G₁And G₂Respectively, cyclic addition and multiplication groups of order large prime q, P being G₁The generator of (1). The bilinear pair is a mapping e.g. between the two cyclic groups₁×G₁→G₂The following properties are satisfied:

(1) bilinear: e (aP, bP) ═ e (P, Q)^abWherein

(2) Non-degradability: presence of P, Q ∈ G₁Let e (P, Q) not equal to 1;

(3) calculability: there is an efficient algorithmic computation of e (P, Q), where P, Q ∈ G₁。

2. Difficulty problem

(1) The computational Diffie-Hellman problem: randomly giving a triplet (P, aP, bP) epsilon G₁Wherein

Calculating abP;

(2) computational co-Diffie-Hellman problem: randomly giving a triplet (P, aP, X) epsilon G₁Wherein

aX is calculated.

(3) Elliptic curve discrete logarithm problem: given P, aP ∈ G₁And calculating a.

3 related technical terms

The technical terms related to the invention are described as follows:

(1) the OBU is an on-board communication unit of a vehicle, and is required to register and preload public system parameters and corresponding public and private keys before joining. When a vehicle runs on a road, related state information needs to be periodically broadcasted, the road environment is improved, and traffic safety is guaranteed;

(2) the trust authority TA (trust authority) is responsible for registering vehicles with OBUs and helps to generate part of the private key and reveal the true identity of the sender if necessary. While requiring sufficient computing and storage capacity;

(3) the VANET (vehicular ad hoc network) is an application of a traditional mobile ad hoc network (MANET) on a traffic road, and is a structural network which integrates a mixed system of direct interconnection between vehicles, indirect interconnection between vehicles and roadside fixed facilities.

(4) Authentication: the message being delivered should be able to be authenticated. To satisfy security (e.g., to prevent impersonation attacks), the accepted information should be generated by the legitimate vehicle. Therefore, all messages must be authenticated by the recipient, regardless of how they were sent or sent.

(5) Anonymity: from the perspective of vehicles, because the vehicles in communication need to communicate with each other, the private information of the vehicles, including the speed, the position and the like, needs to be interacted, and in the process, the authenticity of the interacted information must be ensured, so that the adjacent vehicles can establish a trust relationship, and meanwhile, an attacker is also ensured not to have an opportunity to forge the privacy of the invention. The communication protocol in this should satisfy anonymity.

(6) Traceability: the vehicle may engage in unlawful activities in an anonymous fashion, for example, an insider may issue malicious information. In other words, a suitable communication protocol should satisfy the condition privacy. If disputes occur, the malicious vehicle must be revoked. Thus, the authority (trust authority TA) should reveal the actual identity of the vehicle, if necessary.

(7) Spontaneous property: the ring member list can be selected by the signer, and a signature including the signer can be generated without permission of other ring members.

Secondly, the implementation process of the invention

As shown in fig. 1, the system structure of the present invention is as follows: including the vehicle (OBU), the roadside infrastructure (RSU, not referred to here) and also the trust authority (trust authority TA); in a VANET environment, a trust authority TA is responsible for registering and registering vehicles with OBUs and helping to generate a part of private keys and uncover the real identity of a sender when necessary;

the vehicle of the on board communication unit OBU is responsible for registering and preloading public system parameters and corresponding public and private keys before joining the VANET (vehicle ad hoc network). When the vehicle runs on the road, the related state information is periodically broadcasted, the road environment is improved, and the traffic safety is ensured.

As shown in fig. 3-5, the secure communication of the present invention is implemented as follows:

step one, system initialization stage

In the initialization phase, the invention assumes that each vehicle is equipped with an On Board Unit (OBU) and that there is a third party trust authority TA responsible for checking the identity of the vehicle and for generating and pre-assigning the private key of the vehicle. Before communication, the trust authority TA sets the system parameters for each vehicle OBU as follows:

knowing a safety parameter Z, a trust authority TA (actually executed by the vehicle management centre) outputs a large prime number q, G₁For cyclic addition groups, G₂Is a cyclic multiplicative group. P and Q are G₁Generation ofAnd (5) Yuan. TA selection master private Key

(where S is kept secret) and computes the master public key P_pubSP, wherein e: G₁×G₁→G₂For bilinear pairwise mapping, the 3 hash functions are respectively H₁:{0,1}^*→G₁，

After the initialization phase is complete, the trust authority TA publishes the system parameters (G)₁,G₂,q,P,Q,P_pub,e,H₁,H₂,H₃)。

And step two, a vehicle information preloading stage, wherein after the initialization stage is completed, a vehicle with an OBU needs to preload a key pair. This stage includes partial private key generation and user public private key generation. The key is generated specifically as follows:

(a) given vehicle identity ID_iTA calculation

And will be

Sending the data to the vehicle;

(b) vehicle pass check equation

Whether or not to be established. If true, the vehicle selects a secret value

And calculates the public key Y_i＝x_iP；

(c) Vehicle preload private key pair

Public key pair

And step three, a vehicle safety message generation stage, wherein a signature about the message m needs to be generated before each vehicle in the vehicle-mounted self-organizing network sends the message. At this stage, the invention considers that each type of vehicle requires privacy protection, one vehicle μ_sIt is desirable to propagate messages in a group, assuming that L ═ Y₁,Y₂,…Y_n) Is a vehicle mu_sSet of collected public keys, ω ═ ID₁,ID₂,…ID_nThe corresponding identity set of the vehicle is collected, and the public key set collected here is represented by mu_sTemporarily collected and stored, and this set of public keys is dynamic. These vehicles form a ring μ ═ μ₁,μ₂,…μ_nOne vehicle mu_sIn order to broadcast information such as road conditions, vehicle speed and the like in a formed ring and ensure privacy of the vehicle, the following algorithm is executed:

(a) randomly selecting a secret value

Where (i ═ 1,2 …, n), T is calculated_i＝t_iP，PK_i＝t_ix_iP，

(b) Selection of R_i,K_i∈G₁(i-1, 2 …, n \ s), calculating r_i＝H₂(m||ω||T,R_i,Y_i) Where i is 1,2, … s-1, s +1, …, n, calculating κ_i＝H₃(m||r_i||ω||T,K_i,Y_i) Wherein i is 1,2, … s-1, s +1, …, n;

(c) selecting a secret value

Computing

r_s＝H₂(m||ω||T,R_s,Y_s)，κ_s＝H₃(m||r_s||ω||T,K_s,Y_s)；

(d) Computing

(e) Output signed message σ ═ (R)₁,R₂,…R_n,K₁,K₂,…K_n,V,PK_iT, ω) and broadcasting the signed message in the ring formed by the vehicles;

step four, message verification stage

After the receiver receives the signature, the public key set L ═ Y of n signers is known₁,Y₂,…Y_n) Wherein r is_i＝H₂(m||ω||T,R_i,Y_i)，κ_i＝H₃(m||r_i||ω||T,K_i,Y_i). Next, it is checked whether the following equation is true.

If so, the signature is accepted and the message is considered to be from a reliable ring formed by the vehicle, otherwise the signature is rejected.

Step five, vehicle tracking stage

When a receiver discovers that a signer anonymously leaks false messages or other destructive behaviors, or finds that someone in the area tries to falsify sent information and destroy the communication safety, a temporary ring formed by a vehicle group, namely mu-mu is needed₁,μ₂,…μ_nFind out the real signer mu_sThe vehicle is tracked and its key is recalled. The receiver applies arbitration to the TA, the trust authority TA verifies the validity of the signature, and the real signer mu can be traced through one-time interaction with all members in the ring_s. Wherein the tracing flow chart is shown in fig. 3. The specific tracking verification algorithm process is as follows:

(a) trust authority TA based on PK in output signature message sigma_iCollecting T to corresponding vehicle ring members_iValue, i.e.

(b) Trust authority TA collects all T together_iAfter the value, by judging e (PK)_i,P)＝e(T_i,Y_i) Verification T_iThe effectiveness of (c). If T_iIf not, the corresponding ring member is considered to be a dishonest signer, if T_iIf the result is valid, the following steps are continued;

(c) if T_iValid, then calculate

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. an anonymous authentication method based on a ring signature, is characterized in that, the described anonymous authentication method based on a ring signature on the vehicle network comprises the following steps:

In the first step, the trust organization TA and the vehicle with OBU are registered, and some private keys are generated; the vehicle of the vehicle-mounted communication unit OBU is registered and preloaded with public system parameters and the corresponding public and private keys before joining the vehicle-mounted ad hoc network;

In the second step, when the vehicle is driving on the road, it passes the safety certification and periodically broadcasts the relevant status information; when the signer discovers that the signer anonymously discloses false information or its destruction behavior, the trust agency discloses the true identity of the sender;

The first step specifically includes:

(1) Initialization stage: set system parameters for the OBU of each vehicle, a safety parameter Z is known, and a large prime number q is output by the trust organization TA, G ₁ is a cyclic addition group, G ₂ is a cyclic multiplication group; P, Q For the generator of G ₁ ; the trust authority selects the master private key

where S is kept secret, and the master public key P _pub = SP is calculated, where e: G ₁ ×G ₁ →G ₂ is a bilinear pair mapping, and the three hash functions are H ₁ :{0,1} ^* →G ₁ ,

After the initialization phase is completed, the trust organization discloses the system parameters;

(2) Vehicles with OBU need to preload the key pair, including the private key pair

Generate and user public key pair

Generated; wherein, the trust agency TA secretly stores the label {Y _i , ID _i }, displays the corresponding relationship between the corresponding vehicle identity ID _i and the public key _{Yi, and uses the relationship between the labels {Y i} _, ID _i } in the tracking algorithm to track down to the real identity of the malicious vehicle;

(3) For each vehicle in the vehicle network, generate a signature on the message m before sending the message; each type of vehicle needs privacy protection, a vehicle μ _s wants to spread the message in the group, L = ( Y ₁ , Y ₂ ,...Y _n ) is the public key set collected by the vehicle μ _s , ω={ID ₁ , ID ₂ ,... ID _n } is the corresponding identity set of the vehicle, and the collected public key set is temporarily determined by μ _s Collected and stored; the vehicle forms a ring μ={μ ₁ , μ ₂ , ... μ _n }, forms a signature by executing the message signature algorithm and the identity tracking algorithm and sends the signature;

(4) After receiving the signature, the receiver knows the public key set of n signers L=(Y ₁ , Y ₂ ,...Y _n ), where _ri =H ₂ (m||ω||T, R _i ,Y _i ), κ _i =H ₃ (m||r _i ||ω||T,K _i ,Y _i ); check the following equation

Whether it is established; if it is established, the signature is accepted, and the message is considered to be from a reliable ring formed by the vehicle, otherwise the signature is rejected; where

T _i =t _i P; two generators of R _i ,K _i ∈ G ₁ , which can be 1,2,...,n;

(5) When the receiver finds that the signer anonymously discloses false information or some other destructive behavior, or finds that someone in this area attempts to tamper with the sent information and destroy the communication security, the temporary ring formed from the vehicle group is μ={ Find the real signer μ _s from μ ₁ , μ ₂ ,…μ _n }, trace the car, and then recall its key; the receiver applies to the trust agency TA for arbitration, and the trust agency TA verifies the validity of the signature , and the real signer μ _s can be traced by one interaction with all members of the ring;

Vehicles with OBU need to generate a public-private key pair as required. The process is as follows:

(1) Given the vehicle identity ID _i , the trust agency TA calculates,

and will

sent to the vehicle;

(2) The vehicle passes the inspection equation

Whether it is established to verify; if so, the vehicle selects the secret value

And calculate the public key Y _i = _xi P;

(3) Vehicle preloaded private key pair

public key pair

and broadcast in the temporary ring formed

Vehicles with _OBU can only send a message when a signature is formed in the process of sending a message. The signature forming process is as follows:

(1) Randomly select a secret value

where (i=1,2...,n), calculate T _i =t _i P, PK _i =t _i x _i P,

in

is a secret value for the vehicle;

(2) Select R _i ,K _i ∈G ₁ (i=1,2...,s-1,s+1,...n), and calculate r _i =H ₂ (m||ω||T,R _i , Y _i ), where i=1,2,…s-1,s+1,…,n, calculate κ _i =H ₃ (m||r _i ||ω||T,K _i ,Y _i ), where i=1,2,…s-1,s+1,…,n;

(3) Select the secret value

calculate

r _s =H ₂ (m||ω||T,R _s ,Y _s ), κ _s =H ₃ (m|| _rs ||ω||T,K _s ,Y _s );

(4) Calculation

(5) Output the signed message σ=(R ₁ , R ₂ ,...R _n ,K ₁ ,K ₂ ,... K _n ,V,PK _i ,T,ω) and put the signed message in the vehicle broadcast in the ring;

In the process of vehicle tracking, the interaction process between the trust agency and the vehicle is as follows:

(1) The trust organization collects the T _i value from the corresponding vehicle ring members according to the PK _i in the output signature message σ, that is,

Wherein PK _i =t _i x _i P, used for result verification;

is the secret value of any vehicle;

(2) After the trust organization collects all the T _i values, it verifies the validity of T _i by judging e(PK _i ,P)=e(T _i ,Y _i ); if T _i is invalid, it is considered that the corresponding ring member is the dishonest signer, if T _i is valid, proceed to the following steps;

(3) If T _i is valid, calculate

By verifying that the equation e(T,P)=e(U,Y _i ) is established, find the public key of the real signer μ _s , namely Y _s , and then trace the real signer μ through the label {Y _i , ID _i } _s and recall the key.

2. a ring signature-based vehicle-mounted network anonymous authentication system based on the ring-signature-based vehicle-mounted network anonymous authentication method of claim 1, is characterized in that, the ring signature-based vehicle-mounted network anonymous authentication system comprises:

Trust agency TA, used to register vehicles with OBU and help generate some private keys;

The vehicle of the vehicle-mounted communication unit OBU is used to register and preload the public system parameters and the corresponding public and private keys before joining the vehicle-mounted ad hoc network; when the vehicle is driving on the road, it passes the safety certification and periodically broadcasts the relevant status information; Trust agencies reveal the true identity of the sender when it is discovered that the signer is anonymously disclosing false information or other acts of sabotage.

3. A vehicle communication platform for the ring signature-based vehicle network anonymous authentication method of claim 1.