CN112804646B - Location service algorithm based on re-encryption and pseudonym exchange - Google Patents
Location service algorithm based on re-encryption and pseudonym exchange Download PDFInfo
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04W4/02—Services making use of location information
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Abstract
The invention discloses a location service algorithm based on re-encryption and pseudonym exchange in the technical field of vehicle-mounted networks, which comprises the following steps: s1: establishing a system model; s2: establishing an identity-based encryption and signature function; s3: initial stage S4: track sharing; s5: message transmission; s6: based on a pseudonymous exchange mechanism with similar vehicle behaviors, the user encrypts the track data based on the identity information and transmits the encrypted track data to the traffic information center, and the traffic information center encrypts the track data of the user and transmits the encrypted track data to the corresponding RSU, so that the RSU provides position service for the user. In addition, the algorithm adopts a pseudonym exchange strategy based on similar behaviors, the pseudonym connection attack is defended, the position privacy of the user is protected, the user searches vehicles similar to the behavior of the user in the communication process, and pseudonyms are exchanged with the vehicles, so that the position information of the user is generalized, and the tracked probability is reduced.
Description
Technical Field
The invention relates to the technical field of vehicle-mounted networks, in particular to a location service algorithm based on re-encryption and pseudonym exchange.
Background
Vehicle Networks (VANETs) are novel mobile ad Hoc Networks (MANETs) running on roads, and play an important role in improving vehicle driving safety and dredging traffic flow. By installing the vehicle-mounted unit, the vehicle can complete communication with the neighbor devices (vehicle, nearby devices). Through Vehicle-to-Vehicle (V2V), vehicle-to-Road Side Unit (V2R) communication, the cognitive ability of the Vehicle to the surrounding environment is improved.
As the most promising application, location-based services (LBS) deliver value information for vehicles, including point of interest queries, advertisement push, and entertainment games. According to the trajectory of the vehicle, the efficiency of the location service can be improved. As shown in FIG. 1, assume that sRSSU 1 Vicinity zoneThe domain being a vehicle
The community hotspot area of (1). sRSSU 1 Collecting hot spot area information and giving the information to the vehicle
Location services are provided. Transmitting message strategy based on trace, first, sRSU 1 Vehicle awareness
Then according to the driving path of
Track of (1), sRSSU 1 Passing value information through RSU 1 And RSU 2 Is transmitted along the way to
However, the delivery of trajectory information increases the risk of revealing location privacy leaks. The main reason why the privacy of the user location is revealed is that the location service provider illegally obtains the personal sensitive information of the user, such as family/work address, personal preference, living habits and the like, from the location information submitted by the user by using technologies such as data mining and the like.
The driving route of the vehicle or the position information of the vehicle belong to the private information of the user (driver), and the position privacy is an important component of the security requirements of VANETs. In the trajectory-based message transmission scheme, if a vehicle needs to share its own travel route with an sRSU in a hot spot area, it is necessary to protect the location privacy information of a user. Namely how to share the running track of the user with the sRSSU on the basis of not revealing the privacy of the user's position. In other words, the travel trajectory can only be transmitted to authorized srsus and cannot be exposed to other devices (vehicles, RSUs, etc.).
Most existing vehicle communication privacy protection policies are anonymous authentication based on an alias mechanism. Jeong proposes a model structure for trajectory-based message transmission, but this is based on a control center, and the trajectory of the vehicle is maintained by the control center. However, from the perspective of the driver (user), the control center itself has a safety problem, and the user wants to control which devices can access the driving track data of the device by himself instead of being controlled by the control center.
In addition, pseudonyms are anonymous public key certificates assigned to vehicles, which can both prove the legitimacy of the public key and do not contain any identity information of the vehicle. Therefore, the performance of protecting the privacy of the user can be improved by using the pseudonym policy. However, if the vehicle uses the same pseudonym for a long time, the tracker can associate the travel track of the vehicle according to the pseudonym information in the beacon message, thereby exposing the location privacy of the vehicle. To avoid revealing location privacy, the vehicle no longer uses the same pseudonym, but instead confuses the tracker by continually changing pseudonyms.
Based on the above, the present invention designs a location service algorithm based on re-encryption and pseudonym exchange to solve the above-mentioned problems.
Disclosure of Invention
The invention aims to provide a location service algorithm based on re-encryption and pseudonym exchange, wherein a user encrypts track data by using identity-based information and then transmits the track data to a traffic information center. And the traffic information center encrypts and transmits the track data of the user to the corresponding RSU, and the RSU provides the position service for the user. In addition, the algorithm adopts a pseudonym exchange strategy based on similar behaviors, thereby defending pseudonym connection attack and protecting the position privacy of the user. In the communication process, a user searches vehicles similar to own behaviors and exchanges pseudonyms with the vehicles, so that own position information is generalized and the tracked probability is reduced.
In order to achieve the purpose, the invention provides the following technical scheme: a location service algorithm based on re-encryption and pseudonym exchange, comprising the steps of:
s1: establishing a system model: the whole system mainly comprises law enforcement agencies LEA, traffic information centers TIC, RSUs and vehicles;
s2: establishing an identity-based encryption and signature function, comprising:
a master key generation function Setup (k) for generating a master key by executing Setup ()
Generating a function Extract (id) based on the private key of the identity, and generating the private key according to the function Extract (id) based on the identity id
Wherein pk id ＝H 1 (id)；H 1 {0,1} > → Ghash function;
identity-based encryption function Encrypt (id, m), given identity information id e {0,1} * And message m ∈ G 1 The function Encrypt (id, m) generates a ciphertext c = (c) 1 ,c 2 ) Wherein c is 1 ＝g r ,c 2 ＝m·e(pk id ，pk id ) r ,
Decryption function Decrypt (c, sk) id ) Given the ciphertext c and the private key sk id Function Decrypt (c, sk) id ) Decrypting message m = c 2 /(e(sk id ，c 1 ))；
Re-encryption function
Given the private key sk id And identity id 1 ,id 2 ,
Function output rekeying
Signature function Signid (sk) id M), given the private key sk id And message m, function Signid (sk) id M) generating a signature;
s3: an initial stage: law enforcement agency LEA selects bilinear mapping groups (G, G) with same prime order q T ) And a random parameter G, h is epsilon G, and then a random number is selected
As master key for law enforcement agency LEA and calculates the corresponding public key a = g α The law enforcement agency LEA then selects the Hash function: h 1 :{0,1}*→G，H 2 :{0,1} * →G 2 ，
H 4 :G T → G, regeneration system parameters params:
params＝(G,G T ,q,e,g，h,A，H 1 ，H 2 ,H 3 ,H 4 ) (1)
for the
Law enforcement agency LEA runs Extract (RSU) l ) Function, generate RSU l Private key of
And in advance will
Securely transmit to each RSU l Free vehicle
Registers with the Law Enforcement LEA and obtains a pseudonym PID k While law enforcement agency LEA stores vehicles
ID number ID of k PID with its pseudonym k Associated information Link of k ＝En LEA (IDk,PID k ) In which En LEA A function representing that the law enforcement agency LEA encrypts the associated information by using the own key;
then, the vehicle is reused
Alias PID of k Generating vehicles
Private key of
In the formula:
the law enforcement agency LEA firstly distributes a secret key to the vehicle, and at the later stage, the vehicle exchanges a pseudonym with the vehicle with similar behavior;
suppose a vehicle
The selected hot spot regions are set as
Vehicle with a steering wheel
For each sRSSU j ∈SR k Weight distribution key
Finally, the vehicle
The rekey and hot spot region RSUs list RSM is listed k ＝{PID k ,SR k ,RK k Is transmitted to TIC, where
To prevent the leakage of the vehicle identification information, equation (3) uses the pseudonymous PID of the vehicle k Generating a re-key;
s4: track sharing: the track information transmitted by the vehicle to the TIC comprises the current pseudonym of the vehicle, the position and the speed of the vehicle and the road, and the command trj k ＝<PID k ,x k ,υ k ,Road k >Indicating vehicles
Wherein x is k Indicating vehicles
The position vector of (a); upsilon is k Indicating vehicles
The running speed of (2); road k Indicating vehicles
The name of the current road is obtained, and the vehicle can obtain the information of the current road through the pre-downloaded digital map
Firstly, the ID number of the user is utilized to match the track data trj k Encrypting, transmitting to TIC, and decrypting by TIC to obtain track data after verification is passed; the TIC then encrypts the trajectory data and transmits it to the vehicle
sRSU in the associated hotspot region;
s5: message transmission: once sRSSU is applied j Obtain the vehicle
Track data trj of k ，sRSU j To the vehicle
Providing location service messages, assuming sRSSU j The location service message is msg, RSU t sRSSU as an optimal access point j In order to ensure the safety of message transmission and to connect vehicles
Accurate transmission of required location service messages to vehicles
Instead of other vehicles, encrypts the message, and the vehicle is provided with
The identity of (2) is confirmed, and the specific process is as follows:
first, from sRSSU j Firstly, constructing message msg, then encrypting, firstly calculating parameters
Then calculates the key K 1 = KDF (K | 1) and K 2 = KDF (k | 2) where KDF stands for key derivation function, finally constructing message
Wherein
Then, sRSSU j Forwarding message M to RSU t Upon reception of the message M, RSU t Temporarily storing the message M until the vehicle
Extracts value service message msg from message M when vehicle is running
Travel to RSU t In the coverage of (2), RSU t Then toVehicle transmission
After the vehicle receives the message M, the vehicle
First calculating
Then, K is derived 1 ＝KDF(k|1)，K 2 ＝KDF(k|2)，
Finally, verify
And
whether they are equal, if so, it indicates that the vehicle passes the verification
Then decrypt
Ultimately obtaining a value message
S6: pseudonym exchange mechanism based on similar vehicle behaviors:
based on the vehicle motion track, calculating the position, speed and acceleration of the vehicle and the group motion information of the position, speed and acceleration of the adjacent vehicle, and enabling x i (t)、υ i (t)、α i (t) respectively represent vehicles
Position, velocity and acceleration at time t, similarly, with x j (t)、υ j (t)、α j (t) respectively represent vehicles
Of a neighboring vehicle
Calculating the vehicle using cosine similarity at the position, speed and acceleration at time t
With neighbour vehicles
Behavioral similarity of (c):
in the formula:
is two vectors, if
Then explain
And
the two vectors are either completely similar or identical,
if it is
And λ is a very small number, it means that the two vectors are very similar, so using equation (5), the vehicle can be calculated
And a vehicle
Similarity between position, speed and acceleration when the vehicle is running
And a vehicle
Sum of similarity rates in three aspects of position, velocity and acceleration s i,j If the distance is larger than the threshold value, the behaviors of the two vehicles are considered to be similar, the condition of exchanging the pseudonyms is met, the pseudonyms are exchanged between the vehicles with similar behaviors, the tracked probability is reduced, further the position privacy protection is realized,
in the formula:
and
respectively representing vehicles
And a vehicle
Similarity in three dimensions, position, velocity and acceleration, and ω 1 、ω 2 、ω 3 In order to be the weight coefficient,
when the vehicles need to exchange the pseudonyms, the vehicles search for the vehicles with similar behaviors from the neighbor vehicles, and the vehicles meeting the similar behaviors are brought into the behavior similar vehicle set psi sim_beh (k)：
In the formula: s th Is a behavior similarity threshold; integrated psi sim_beh (k) The more the number of the vehicles in the vehicle, the more the vehicle is
The more vehicles that behave similarly, the more vehicles
The larger the space where the position is generalized, therefore, num = | ψ sim_beh (k) | is defined as a vehicle
The larger the Num value is, the better the anonymity effect is, the better the performance of the position privacy protection is,
when the vehicle is running
If the pseudonym needs to be replaced, the request Req is sent to the LEA, the request message is encrypted by using the LEA public key and signed, after the request Req is received, the LEA decrypts the request Req by using the private key of the LEA, the message content is extracted, the signature is verified again, whether the two exchange vehicles are registered vehicles is verified, and if the two exchange vehicles pass the verification, the LEA informs the vehicles
Using new pseudonym PIDs i And simultaneously notify the vehicle
Its pseudonym is PID k 。
Preferably, said law enforcement agency LEA is adapted to
Receiving a registration from a vehicle, and issuing a digital certificate and a pseudonym to the vehicle after the vehicle passes the audit;
monitoring vehicle behaviors, wherein when disputes occur, a law enforcement agency LEA is responsible for tracking related vehicles, and when necessary, canceling digital certificates and pseudonyms of the vehicles;
for assigning an identity-based key to the RSU;
the traffic information center is used for
Collecting traffic information, namely, undertaking the function of information collection;
collecting track data of a vehicle, and forwarding the track data to a service hotspot (sRSSU) allowed by the vehicle;
the RSU receives vehicle track data transmitted by TIC and transmits information to relevant vehicles so as to provide position service for the vehicles, the system has m registered RSUs which form an RSU set
Wherein l RSUs are positioned in the hot spot region, the RSUs positioned in the hot spot region are expressed as sRSUs, and the l sRSUs form a hot spot region RSU set
The system is provided with n vehicles, and each vehicle downloads a digital map to order the sRSU k Indicating vehicles
Selected hotspot RSU, and k =1,2, …, n.
Preferably, G, G T There is a bilinear map pair e G → G 1 They satisfy the following characteristics:
bilinear: for the
And G belongs to G and satisfies e (G) a ,g b )＝e(g,g) ab ；
Non-degeneration: if G is a generator of G, then e (G, G) is G T A generator;
it can be calculated: for any G, h ∈ G, then there is an efficient algorithm to compute e (G, h).
Preferably, the S4 specifically includes the following steps:
s4.1: encryption of track data by vehicle:
in order to share the travel path data trj with the RSUs in the hot-spot region k Vehicle
Using identity ID k For trj k EncryptionThen, the encrypted trj is used k Transmitting to TIC:
firstly setting a cryptograph C = (C) 1 ,c 2 ,c 3 ,c 4 ) As shown in formula (7):
C＝(c 1 ,c 2 ,c 3 ,c 4 )←Encrypt(ID k ,trj k ) (7)
in the formula:
c 1 ＝h r ，c 2 ＝g r ，c 4 ＝H 1 (c 1 |c 2 |c 3 ) r ；r＝H 3 (trj k |θ)，θ∈G，
the encrypted tracks are then merged into a message TM k ＝ID k ||C||ts||σ d To TIC, wherein
Indicating vehicles
The signature of (2); t is t s A presentation time stamp; "|" represents a connector;
s4.2: TIC trj d Data transmission to the hotspot area:
upon receiving TM k TIC first verifies the vehicle
If the signature is valid, the TIC encrypts the ciphertext, and the specific process is as follows:
first, verify e (c) 1 G) and e (h, c) 2 ) If not, TIC directly discards TM k (ii) a Otherwise, continue to verify e (c) 1 ,H 1 (c 1 |c 2 |c 3 ) And e (h, c) 4 ) Whether they are equal; if equal, go to the second step, otherwise directly discard TM k ，
Second, for TM k Carries out decryption and obtainsGet vehicle
The related information of (2): RSM k ＝{PID k ,SR k ,RK k }；
Thirdly, extracting the key
And then ciphertext C = (C) 1 ,c 2 ,c 3 ,c 4 ) Conversion to C '= (C' 1 ,c′ 2 ,c′ 3 ,c′ 4 ) The definition is shown in formula (8):
in the formula: c' 1 ＝c 2 ，c′ 2 ＝c 3 ，
Finally, TIC to sRSSU j Providing a transfer message
Thereby enabling sRSSU j Obtaining vehicles
Track data trj of k ；
S4.3: the hot spot region sRSU decrypts the track data:
receive from
Then, sRSSU j Then obtain C' and ts information, and then run decryption function Decrypt (·) to extract track data trj k I.e. by
The specific process is as follows:
the first step, calculating:
second, calculating
Recalculated r = H 3 (trj k ||θ)；
Finally, verify g r And c' 1 Whether they are equal, if so, vehicle trajectory data trj may be obtained k 。
Compared with the prior art, the invention has the beneficial effects that: and the user encrypts the track data based on the identity information and transmits the track data to the traffic information center. And the traffic information center encrypts and transmits the track data of the user to the corresponding RSU, and the RSU provides the position service for the user. In addition, the algorithm adopts a pseudonym exchange strategy based on similar behaviors, thereby defending pseudonym connection attack and protecting the position privacy of the user. In the communication process, the user searches vehicles similar to own behaviors and exchanges pseudonyms with the vehicles, so that own position information is generalized, and the tracked probability is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of trace-based message transmission according to the present invention;
FIG. 2 is a schematic diagram of the system of the present invention;
FIG. 3 is a diagram of the message msg transmission process of the present invention;
FIG. 4 shows a vehicle and RSU of the present invention t The message passing process between them is shown schematically.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a technical scheme that: a location services algorithm based on re-encryption and pseudonymization, characterized by: the method comprises the following steps:
s1: establishing a system model: the whole system mainly comprises law enforcement agencies LEA, traffic information centers TIC, RSUs and vehicles, and is shown in FIG. 2;
the Law enforcement agency LEA is used for
Receiving a registration from a vehicle, and issuing a digital certificate and a pseudonym to the vehicle after the vehicle passes the audit;
monitoring vehicle behaviors, wherein when disputes occur, a law enforcement agency LEA is responsible for tracking related vehicles, and when necessary, canceling digital certificates and pseudonyms of the vehicles;
for assigning an identity-based key to the RSU;
the traffic information center is used for
Collecting traffic information, namely, undertaking the function of information collection;
collecting track data of a vehicle, and forwarding the track data to a service hotspot sRSU allowed by the vehicle;
the RSU receives vehicle track data transmitted by TIC and transmits information to relevant vehicles so as to provide position service for the vehicles, the system has m registered RSUs which form an RSU set
Wherein l RSUs are located in the hotspot region, willThe RSUs in the hot spot region are expressed as sRSSU, and the sRSSU forms a hot spot region RSU set
The system is provided with n vehicles, and each vehicle downloads a digital map to order the sRSU k Indicating vehicles
Selected hotspot RSU, and k =1,2, …, n.
S2: establishing an identity-based encryption and signature function, comprising:
a master key generation function Setup (k) for generating a master key by executing Setup ()
Generating a function Extract (id) based on the private key of the identity, and generating the private key according to the function Extract (id) based on the identity id
Wherein pk id ＝H 1 (id)；H 1 {0,1 }. → Ghash function;
identity-based encryption function Encrypt (id, m), given identity information id e {0,1} * And message m ∈ G 1 The function Encrypt (id, m) generates the ciphertext c = (c) 1 ,c 2 ) Wherein c is 1 ＝g r ,c 2 ＝m·e(pk id ，pk id ) r ,
Decryption function Decrypt (c, sk) id ) Given the ciphertext c and the private key sk id Function Decrypt (c, sk) id ) Decrypting message m = c 2 /(e(sk id ，c 1 ))；
Re-encryption function
Given the private key sk id And identity id 1 ,id 2 ,
Function output rekeying
The signature function Signid (ski), given the private key sk id And message m, function Signid (sk) id M) generating a signature;
s3: an initial stage: law enforcement agency LEA selects bilinear mapping groups (G, G) with same prime order q T ) And a random parameter G, h ∈ G, G, G T There is a bilinear map pair e G → G 1 They satisfy the following characteristics:
bilinear: for the
And G belongs to G and satisfies e (G) a ,g b )＝e(g,g) ab ；
Non-degenerate: if G is a generator of G, then e (G, G) is G T A generator;
it can be calculated: for any G, h ∈ G, then there is an efficient algorithm to compute e (G, h).
Then selecting a random number
As master key for law enforcement agency LEA and calculates the corresponding public key a = g α The law enforcement agency LEA then selects the Hash function: h 1 :{0,1} * →G，H 2 :{0,1} * →G 2 ,
H 4 :G T → G, regeneration system parameters params:
params＝(G,G T ,q,e,g,h,A,H 1 ,H 2 ,H 3 ,H 4 ) (1)
for the
Law enforcement agency LEA runs Extract (RSU) l ) Function, generate RSU l Private key of
And in advance will
Securely transmit to each RSU l Free vehicle
Registers with the Law Enforcement LEA and obtains a pseudonym PID k While law enforcement agency LEA stores vehicles
ID number ID of k PID with its pseudonym k Associated information Link of k ＝En LEA (ID k ,PID k ) In which En LEA A function indicating that the law enforcement agency LEA encrypts the associated information by using the key of the law enforcement agency LEA;
then, the vehicle is reused
Alias PID of k Generating vehicles
Private key of
In the formula:
the law enforcement agency LEA firstly distributes a secret key to the vehicle, and later, the vehicle is handed over with the vehicle similar to the behavior of the vehicleChanging the pseudonyms;
suppose a vehicle
The selected hot spot regions are set as
Vehicle with a steering wheel
For each sRSSU j ∈SR k Weight distribution key
Finally, the vehicle
The rekey and hot spot region RSUs list RSM is listed k ＝{PID k ,SR k ,RK k Is transmitted to TIC, where
To prevent the leakage of the vehicle identification information, equation (3) uses the pseudonymous PID of the vehicle k Generating a re-key;
s4: track sharing: the track information transmitted by the vehicle to the TIC comprises the current pseudonym of the vehicle, the position, the speed and the road, so that trj is k ＝<PID k ,x k ,υk,Road k >Indicating vehicles
Wherein x is k Indicating vehicles
The position vector of (a); v is a cell k Indicating vehicles
The running speed of (2); road k Indicating vehicles
The name of the current road is obtained by the vehicle through the pre-downloaded digital map, and the vehicle can obtain the information of the current road
Firstly, the ID number of the user is utilized to pair the track data trj k Encrypting, transmitting to TIC, and decrypting by TIC to obtain track data after verification is passed; the TIC then encrypts the trajectory data and transmits it to the vehicle
sRSU in the associated hotspot region;
s4.1: encryption of track data by vehicle:
in order to share the travel path data trj with the RSUs in the hot-spot region k Vehicle, vehicle
Using identity ID k For trj k Encrypting, and encrypting trj k Transmitting to TIC:
firstly setting up encrypted text C = (C) 1 ,c 2 ,c 3 ,c 4 ) As shown in formula (7):
C＝(c 1 ,c 2 ,c 3 ,c 4 )←Encrypt(ID k ,trj k ) (7)
in the formula:
c 1 ＝h r ，c 2 ＝g r ，c 4 ＝H 1 (c 1 |c 2 |c 3 ) r ；r＝H 3 (trj k |θ)，θ∈G，
then, the encrypted tracks are fused into a hashMessage TM k ＝ID k ||C||ts||σ d To TIC, wherein
Indicating vehicles
The signature of (2); t is t s Represents a time stamp; "|" represents a connector;
s4.2: TIC trj d Data transmission to the hotspot area:
upon receiving TM k TIC first verifies the vehicle
If the signature is valid, the TIC encrypts the ciphertext, and the specific process is as follows:
first, verify e (c) 1 G) and e (h, c) 2 ) If not, TIC directly discards TM k (ii) a Otherwise, continue to verify e (c) 1 ,H 1 (c 1 |c 2 |c 3 ) And e (h, c) 4 ) Whether they are equal; if equal, go to the second step, otherwise directly discard TM k ，
Second step, to TM k Decrypt and obtain the vehicle
The related information of (2): RSM k ＝{PID k ,SR k ,RK k }；
Thirdly, extracting the key
And then ciphertext C = (C) 1 ,c 2 ,c 3 ,c 4 ) Conversion to C '= (C' 1 ,c′ 2 ,c′ 3 ,c′ 4 ) And is defined as shown in formula (8):
in the formula: c' 1 ＝c 2 ，c′ 2 ＝c 3 ，
Finally, TIC to sRSSU j Providing a transfer message
Thereby enabling sRSSU j Obtaining vehicles
Track data trj of k ；
S4.3: the hot spot region sRSU decrypts the track data:
receive from
Then, sRSSU j Then obtain C' and ts information, and then run decryption function Decrypt (·) to extract track data trj k I.e. by
The specific process is as follows:
the first step, calculate:
second, calculating
Recalculated r = H 3 (trj k ||θ)；
Finally, g is verified r And c' 1 Whether they are equal, if so, vehicle trajectory data trj may be obtained k 。
S5: message transmission: once sRSSU is applied j Obtain the vehicle
Track data trj of k ，sRSU j To the vehicle
Providing location service messages, assuming sRSSU j The location service message is msg, RSU t For the optimal access point, the message msg transmission process is shown in fig. 3. sRSSU j In order to ensure the safety of message transmission and to connect vehicles
Accurate transmission of required location service messages to vehicles
Instead of other vehicles, encrypts the message, and the vehicle is provided with
The identity of (2) is confirmed, and the specific process is as follows:
first, the sRSSU is used j Firstly, constructing message msg, then encrypting, firstly calculating parameters
Then calculates the key K 1 = KDF (K | 1) and K 2 = KDF (k | 2) where KDF stands for key derivation function, finally constructing message
Wherein
Then, sRSSU j Forwarding message M to RSU t Upon reception of the message M, RSU t Temporarily storing the message M until the vehicle
The value service message msg is extracted from the message M, and the specific process is shown in fig. 4.
When the vehicle is running
Travel to RSU t In the coverage area of (RSU), RSU t Is transmitted to the vehicle
After the vehicle receives the message M, the vehicle
First calculate
Then, K is derived 1 ＝KDF(k|1)，K 2 ＝KDF(k|2)，
Finally, verify
And
if not, if so, indicating that the vehicle passes the verification
Then decrypt
Ultimately obtaining a value message
S6: pseudonym exchange mechanism based on vehicle behavior similarity:
based on the vehicle motion track, calculating the position, speed and acceleration of the vehicle and the group motion information of the position, speed and acceleration of the adjacent vehicle, and enabling x i (t)、υ i (t)、α i (t) respectively represent vehicles
Position, velocity and acceleration at time t, similarly, with x j (t)、υ j (t)、α j (t) respectively represent vehicles
Of a neighboring vehicle
Calculating the vehicle using cosine similarity at the position, velocity and acceleration at time t
With neighbour vehicles
Behavioral similarity of (c):
in the formula:
is two vectors, if
Then explain
And
the two vectors are either completely similar or identical,
if it is
And λ is a very small number, then the two vectors are very similar, so the formula is used(5) Vehicle capable of calculating
And a vehicle
Similarity between position, speed and acceleration when the vehicle is running
And a vehicle
Sum of similarity rates in three aspects of position, velocity and acceleration s i,j If the distance is larger than the threshold value, the behaviors of the two vehicles are considered to be similar, the condition of exchanging the pseudonyms is met, the pseudonyms are exchanged between the vehicles with similar behaviors, the tracked probability is reduced, further the position privacy protection is realized,
in the formula:
and
respectively representing vehicles
And a vehicle
Similarity in three aspects of position, velocity and acceleration, and ω 1 、ω 2 、ω 3 In order to be a weight coefficient of the image,
when the vehicles need to exchange the pseudonyms, the vehicles search for the vehicles with similar behaviors from the neighbor vehicles, and the vehicles meeting the similar behaviors are brought into the behavior similar vehicle set psi sim_beh (k)：
In the formula: s th Is a behavior similarity threshold; integrated psi sim_beh (k) The more vehicles in the vehicle, the more vehicles are indicated
The more vehicles behave similarly, the more vehicles
The larger the space where the position is generalized, therefore, num = | ψ sim_beh (k) I is defined as a vehicle
The larger the Num value is, the better the anonymity effect is, the better the performance of the position privacy protection is,
when the vehicle is running
If the pseudonym needs to be replaced, the request Req is sent to the LEA, the request message is encrypted by using the LEA public key and signed, after the request Req is received, the LEA decrypts the request Req by using the private key of the LEA, the message content is extracted, the signature is verified again, whether the two exchange vehicles are registered vehicles is verified, and if the two exchange vehicles pass the verification, the LEA informs the vehicles
Employing a new pseudonym PID i And simultaneously notify the vehicle
Its pseudonym is PID k 。
In order to achieve conditional privacy protection, the law enforcement agency LEA maintains the operational procedures of vehicle exchange pseudonyms. From this process information, the law enforcement agency LEA can track the vehicle when a dispute occurs.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (3)
1. A location services algorithm based on re-encryption and pseudonymization, characterized by: the method comprises the following steps:
s1: establishing a system model: the whole system mainly comprises a law enforcement agency LEA, a traffic information center TIC, RSUs and vehicles;
s2: establishing an identity-based encryption and signature function, comprising:
a master key generation function Setup (k) for generating a master key by executing Setup ()
Generating a function Extract (id) based on the private key of the identity, and generating the private key according to the function Extract (id) based on the identity id
Wherein pk id ＝H 1 (id)；H 1 {0,1} > → Ghash function;
identity-based encryption function Encrypt (id, m), given identity information id e {0,1} * And message m ∈ G 1 The function Encrypt (id, m) generates the ciphertext c = (c) 1 ,c 2 ) Wherein c is 1 ＝g r ,c 2 ＝m·e(pk id ，pk id ) r ,
Decryption function Decrypt (c, sk) id ) Given the ciphertext c and the private key sk id Function Decrypt (c, sk) id ) Decrypting message m = c 2 /(e(sk id ，c 1 ))；
Re-encryption function
Given the private key sk id And identity id 1 ,id 2 ,
Function output rekeying
Signature function Signid (sk) id M), given the private key sk id And message m, function Signid (sk) id M) generating a signature;
s3: an initial stage: law enforcement agency LEA selects bilinear mapping groups (G, G) with same prime order q T ) And a random parameter G, h e G, and then selecting a random number
As master key for law enforcement agency LEA and calculates the corresponding public key a = g α The law enforcement agency LEA then selects the Hash function: h 1 ：{0，1} * →G，H 2 ：{0，1} * →G 2 ，H 3 ：
H 4 :G T → G, regeneration system parameters params:
params＝(G,G T ,q,e,g,h,A,H 1 ,H 2 ,H 3 ,H 4 ) (1)
for
Law enforcement agency LEA operation
Function, generate
Private key of
And in advance will
Is safely transmitted to each
Arbitrary vehicle
Registers with the Law Enforcement LEA and obtains a pseudonym PID k While law enforcement agency LEA stores vehicles
ID number ID of k PID with its pseudonym k Associated information Link of k ＝En LEA (ID k ,PID k ) In which En LEA A function indicating that the law enforcement agency LEA encrypts the associated information by using the key of the law enforcement agency LEA;
then, the vehicle is reused
Alias PID of k Generating vehicles
Private key of
In the formula:
the law enforcement agency LEA firstly distributes a secret key to the vehicle, and at the later stage, the vehicle exchanges a pseudonym with the vehicle with similar behavior;
suppose a vehicle
The selected hot spot regions are set as
Vehicle with a steering wheel
For each sRSSU j ∈SR k Weight distribution key
Finally, the vehicle
The rekey and hot spot region RSUs list RSM is listed k ＝{PID k ,SR k ,RK k Is transmitted to TIC, where
To prevent the leakage of the vehicle identification information, equation (3) uses the pseudonymous PID of the vehicle k Generating a re-key;
s4: track sharing: the track information transmitted by the vehicle to the TIC comprises the current pseudonym of the vehicle, the position and the speed of the vehicle and the road, and the command trj k ＝<PID k ,x k ,υ k ,Road k >Indicating vehicles
Wherein x is k Indicating vehicles
A position vector of (a); upsilon is k Indicating vehicles
The running speed of (2); road k Indicating vehicles
The name of the current road is obtained by the vehicle through the pre-downloaded digital map, and the vehicle can obtain the information of the current road
Firstly, the ID number of the user is utilized to pair the track data trj k Encrypting, transmitting to TIC, and decrypting by TIC to obtain track data after verification is passed; the TIC then encrypts the trajectory data and transmits it to the vehicle
The sRSSU in the associated hotspot region;
s5: message transmission: once sRSSU is applied j Obtain a vehicle
Track data trj of k ，sRSU j To the vehicle
Providing location service messages, assuming sRSSU j The location service message is msg, RSU t For optimal access point, sRSSU j In order to ensure the safety of message transmission and to connect a vehicle
Accurate transmission of required location service messages to vehicles
Instead of other vehicles, encrypts the message, and the vehicle is provided with
The identity of (2) is confirmed, and the specific process is as follows:
first, the sRSSU is used j Firstly, constructing message msg, then encrypting, firstly calculating parameters
Then calculates the key K 1 = KDF (K | 1) and K 2 = KDF (k | 2) where KDF stands for key derivation function, finally constructing message
Wherein
Then, sRSSU j Forwarding message M to RSU t Upon reception of the message M, RSU t Temporarily storing the message M until the vehicle
Extracts the value service message msg from the message M when the vehicle is
Travel to RSU t In the coverage area of (RSU), RSU t Is transmitted to the vehicle
After the vehicle receives the message M, the vehicle
First calculate
Then, K is derived 1 ＝KDF(k|1)，K 2 ＝KDF(k|2)，
Finally, verify
And with
Whether they are equal, if so, it indicates that the vehicle passes the verification
Then decrypt
Ultimately obtaining a value message
S6: pseudonym exchange mechanism based on vehicle behavior similarity:
based on the motion track of the vehicle, the position, the speed and the acceleration of the vehicle and the position, the speed and the acceleration of the adjacent vehicle are calculated,Group motion information of acceleration, let x i (t)、υ i (t)、α i (t) respectively represent vehicles
Position, velocity and acceleration at time t, similarly, with x j (t)、υ j (t)、α j (t) respectively represent vehicles
Of a neighboring vehicle
Calculating the vehicle using cosine similarity at the position, speed and acceleration at time t
With neighbour vehicles
Behavioral similarity of (c):
in the formula:
is two vectors, if
Then explain
And
the two vectors are either completely similar or identical,
if it is
And λ is a very small number, it means that the two vectors are very similar, so using equation (5), the vehicle can be calculated
And a vehicle
Similarity between position, speed and acceleration when the vehicle is running
And a vehicle
Sum of similarity rates in three aspects of position, velocity and acceleration s i,j If the distance is larger than the threshold value, the behaviors of the two vehicles are considered to be similar, the condition of exchanging the pseudonyms is met, the pseudonyms are exchanged between the vehicles with similar behaviors, the tracked probability is reduced, further the position privacy protection is realized,
in the formula:
and
respectively representing vehicles
And a vehicle
At three positions, velocities and accelerationsSimilarity of aspects, and ω 1 、ω 2 、ω 3 In order to be the weight coefficient,
when the vehicles need to exchange the pseudonyms, the vehicles search for the vehicles with similar behaviors from the neighbor vehicles, and the vehicles meeting the similar behaviors are brought into the behavior similar vehicle set psi sim_beh (k)：
In the formula: s is th Is a behavior similarity threshold; integrated psi sim_beh (k) The more the number of the vehicles in the vehicle, the more the vehicle is
The more vehicles that behave similarly, the more vehicles
The larger the space where the position is generalized, therefore, num = | ψ sim_beh (k) | is defined as a vehicle
The larger the Num value is, the better the anonymity effect is, the better the performance of the position privacy protection is,
when the vehicle is running
If the pseudonym needs to be replaced, the request Req is sent to the LEA, the request message is encrypted by using the LEA public key and signed, after the request Req is received, the LEA decrypts the request Req by using the private key of the LEA, the message content is extracted, the signature is verified again, whether the two exchange vehicles are registered vehicles is verified, and if the two exchange vehicles pass the verification, the LEA informs the vehicles
Employing a new pseudonym PID i And simultaneously notify the vehicleVehicle with a motor
Its pseudonym is PID k ；
The law enforcement agency LEA is arranged to,
receiving a registration from a vehicle, and issuing a digital certificate and a pseudonym to the vehicle after the vehicle passes the audit;
monitoring vehicle behaviors, wherein when disputes occur, a law enforcement agency LEA is responsible for tracking related vehicles, and when necessary, canceling digital certificates and pseudonyms of the vehicles;
for assigning an identity-based key to the RSU;
the traffic information center is used for receiving the traffic information,
collecting traffic information, namely, undertaking the function of information collection;
collecting track data of a vehicle, and forwarding the track data to a service hotspot sRSU allowed by the vehicle;
the RSU receives the vehicle track data transmitted by the TIC and transmits messages to related vehicles so as to provide position service for the vehicles, the system has m registered RSUs, and the registered RSUs form an RSUS set
Wherein l RSUs are positioned in the hot spot region, the RSUs positioned in the hot spot region are expressed as sRSUs, and the l sRSUs form a hot spot region RSU set
The system is provided with n vehicles, and each vehicle downloads a digital map to order the sRSU k Indicating vehicles
Selected hotspot RSU, and k =1,2, …, n.
2. A location services algorithm based on re-encryption and pseudonymization as claimed in claim 1, characterized in that: G. g T There is a bilinear mapping pair e G→G 1 They satisfy the following characteristics:
bilinear: for the
And G belongs to G and satisfies e (G) a ,g b )＝e(g,g) ab ；
Non-degeneration: if G is a generator of G, then e (G, G) is G T A generator;
it can be calculated: for any G, h ∈ G, then there is an efficient algorithm to compute e (G, h).
3. A location services algorithm based on re-encryption and pseudonymization as claimed in claim 1, characterized in that: the S4 specifically comprises the following steps:
s4.1: encryption of track data by vehicle:
in order to share the travel path data trj with the RSUs in the hot-spot region k Vehicle
Using identity ID k For trj k Encrypting, and encrypting trj k Transmitting to TIC:
firstly setting up encrypted text C = (C) 1 ,c 2 ,c 3 ,c 4 ) As shown in formula (7):
C＝(c 1 ,c 2 ,c 3 ,c 4 )←Encrypt(ID k ,trj k ) (7)
in the formula:
c 1 ＝h r ，c 2 ＝g r ，c 4 ＝H 1 (c 1 |c 2 |c 3 ) r ；r＝H 3 (trj k |θ)，θ∈G，
the encrypted tracks are then merged into a message TM k ＝ID k ||C||ts||σ d To TIC, wherein
Indicating vehicles
The signature of (2); ts denotes a time stamp; "|" represents a connector;
s4.2: TIC trj d Data transmission to the hotspot area:
upon receiving TM k TIC first verifies the vehicle
If the signature is valid, the TIC encrypts the ciphertext, and the specific process is as follows:
first, verify e (c) 1 G) and e (h, c) 2 ) If not, then TIC discards TM directly k (ii) a Otherwise, continue to verify e (c) 1 ,H 1 (c 1 |c 2 |c 3 ) And e (h, c) 4 ) Whether they are equal; if equal, go to the second step, otherwise directly discard TM k ，
Second, for TM k Decrypt and obtain the vehicle
The related information of (2): RSM k ＝{PID k ,SR k ,RK k }；
Thirdly, extracting the key
And then ciphertext C = (C) 1 ,c 2 ,c 3 ,c 4 ) Conversion to C '= (C' 1 ,c′ 2 ,c′ 3 ,c′ 4 ) The definition is shown in formula (8):
in the formula: c' 1 ＝c 2 ，c′ 2 ＝c 3 ，
Finally, TIC to sRSSU j Providing a transfer message
Thereby enabling sRSSU j Obtaining vehicles
Track data trj of k ；
S4.3: the hot spot region sRSU decrypts the track data:
receive from
Then, sRSSU j Then obtain C' and ts information, and run decryption function Decrypt (-) to extract track data trj k I.e. by
The specific process is as follows:
the first step, calculate:
second, calculating
Recalculated r = H 3 (trj k ||θ)；
Finally, g is verified r And c' 1 Whether or not they are equal to each other,if equal, vehicle trajectory data trj may be obtained k 。
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