CN116233843A - B5G/6G network slice authentication method for industrial Internet - Google Patents

Abstract

The invention discloses a B5G/6G network slice authentication method oriented to the industrial Internet, which mainly solves the problems of complex network slice authentication flow and certificate management and high cost in the prior art. The implementation scheme is as follows: the third party key generation center generates a signature private key based on the user equipment identity by adopting a certificate-free mode; the user equipment selects a proper slice according to own service requirements; the user equipment initiates a connection request for the selected slice, and signs a request message based on an SM2 digital signature algorithm; selecting a slice to verify the request of the user equipment, negotiating a session key with the user equipment, encrypting a response message which is successfully verified by the session key, and sending the response message to the user equipment; the user equipment decrypts the response message to complete authentication. The invention does not need a certificate, improves the signature speed, simplifies the authentication flow of the slice and the user equipment, reduces the communication and calculation cost, and can be used for the B5G/6G network in the industrial Internet.

Description

B5G/6G Network Slicing Authentication Method for Industrial Internet

technical field

The invention belongs to the technical field of computer security, and in particular relates to a B5G/6G network slice authentication method, which can be used in B5G/6G networks in the industrial Internet.

technical background

In the application of industrial Internet collaborative manufacturing, different business scenarios or different user equipment have very different requirements for low latency, high connection, security and reliability, and network functions. If a network is built separately for each business There will be huge costs, but if only the same network is used, it is difficult to meet different needs. Therefore, in order to provide differentiated assurance services for different services and realize the flexibility of network deployment, the existing technology proposes the requirement of network slicing. Different slices can not only share network physical resources, but also be logically independent and isolated from each other. Flexible adaptation to different business scenarios, and the isolation of slices enables each network slice to run independently without interfering with other running network slices. Although network slicing brings many advantages, security issues also arise. Therefore, it is particularly important to study the slice security service model in the B5G/6G network environment. One of slice security services is to study slice authentication and authorization mechanisms to prevent illegal access to slices. If there is no slice authentication and authorization mechanism, operators may not be able to effectively meet the business needs of different industries, and they will also face potential threats when interacting with third-party networks. Therefore, the issue of security authentication for network slicing is a hotspot of current research.

3GPP proposed a secondary authentication mechanism for 5G slicing in the research on enhanced security of network slicing. After the user and core network complete the primary authentication, user ID and credentials are used to perform secondary authentication at the slice level. The secondary authentication architecture is based on scalable Authentication protocol EAP. When the user equipment connects to the network, it initiates a registration request to the core network. The request message should indicate whether slice authentication and authorization is required. The main authentication process is completed based on the 5G-AKA or EAP-AKA' authentication protocol. During the main authentication, the network elements with unified data management functions The UDM judges whether the user needs specific slice authentication by checking the flag for additional authentication, and then, the access mobility management network element AMF triggers the second authentication process of the specific slice according to the request information. However, this authentication method requires users to deploy public key infrastructure PKI and apply for public key certificates. Certificate management is complex, and certificate issuance, revocation, verification, and storage also require more resources, which limits the application of PKI in real-time environments.

The patent document with the application number CN201910998988 proposes an IoT security verification framework and service method based on 5G network slicing. In order to ensure the anonymity and authenticity of users and the confidentiality of data, an Connect, select the appropriate network slice according to the type of access service, and access the corresponding IoT service anonymously. However, in this method, since the user needs to re-authenticate when switching between different network slices, the authentication process is complicated and the calculation overhead is high. At the same time, the authentication process also needs to interact with many security network elements, resulting in a large transmission delay.

In an article published in the Journal of Computer Communications in 2021, Yinghui Zhang et al. proposed a flexible and anonymous network slicing method FANS, which is based on the AKA protocol to achieve mutual authentication between users and network slices. The public key associated with the actual identity is hidden to protect user identity privacy, and the one-to-many matching technology used based on anonymous attribute-based encryption realizes fine-grained network slice selection. However, since this method uses public key blind technology to realize user identity privacy protection, it will bring additional computing overhead on the user side.

Although the above-mentioned existing technologies have proposed reasonable solutions for security authentication of slices, further research on lightweight network slice authentication methods is needed for the scenario where a large number of user devices are connected to the industrial Internet.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the above-mentioned existing technologies, and propose an authentication method for B5G/6G network slicing facing the industrial Internet, so as to realize fine-grained selection and lightweight authentication of user equipment and network slicing, and reduce calculation and communication overhead, reduce latency, and from the perspective of privacy protection, realize the hiding of user equipment identity and slice feature information.

In order to achieve the above purpose, the B5G/6G network slice authentication method for the industrial Internet of the present invention includes the following steps:

(1) Generate the signature private key d _uc based on the user equipment identity ID _u :

(1a) The third-party key generation center KGC selects public parameters, specifies a large prime number p, takes a base point G whose order is n on the elliptic curve on the finite field F _p , and randomly selects a number in 1<x<n x, set system private key SK _S =x, system public key PK _S =x*G, generate system public-private key pair (PK _S , SK _S =x);

(1b) KGC randomly selects the number y _u in 1<y _u <n, and calculates a point Y _u =y _u *G on the elliptic curve, the hash value h _u =H(ID _u ||Y _u ), the signature private Key d _uc =y _u +SK _S *h _u , send the three parameters d _uc , Y _u , T ₁ to the user equipment UE through a secure channel, where T ₁ is the current timestamp, H() means one-way hash Xi function;

(1c) After the user equipment UE receives the information from the third-party key generation center KGC, it first checks the validity of _T1 :

If valid, execute (1d);

If invalid, the user equipment UE does not accept the signature private key d _uc ;

(1d) Verify that d _uc *G=Y _u +h _u *PK _S is established:

If established, the user equipment UE accepts the signature private key d _uc ;

Otherwise, the user equipment UE does not accept the signature private key d _uc ;

(2) The user equipment UE selects an appropriate slice access according to its own business scenario requirements:

(2a) Divide the physical network resource PNR into l logically independent fine-grained network slices according to the characteristics of rate, throughput, bandwidth, delay, scalability, and security level, and each network slice is expressed as the following feature vector:

S _i F＝{S _i F ₁ ,S _i F ₂ ,…,S _i F _t ,…,S _i F _T }

Where i∈[1,l], S _i F _t represents the t-th eigenvalue of slice i, and T is the number of slice features;

(2b) The user equipment UE constructs the requested slice feature vector according to its own service requirements, encrypts and processes the feature value of the feature vector with a random number, and initiates a slice selection request;

(2c) The access mobility management network element AMF encrypts the characteristic value of each slice in the list according to the slice list set allowed by the user equipment UE and sends it to the user equipment UE;

(2d) After the user equipment UE receives the encrypted slice list set, it calculates the Euclidean distance between the encrypted slice list set and the requested slice feature vector, and selects the slice with the smallest Euclidean distance in the slice list set as the slice for the user equipment UE according to the service The most suitable slice to be selected;

(3) The user equipment UE initiates and selects a connection authentication request for a slice, uses a signature algorithm to sign the request information M, generates signature information (r, s), and sets five Y _u , r, s, M, T ₂ Parameters sent to the selection slice, where T ₂ is the current timestamp;

(4) The slice responds to the request of the user equipment UE by verifying the signature algorithm:

(4a) After receiving the request message sent by the user equipment UE, the slice first verifies whether the timestamp T ₂ is valid:

If it is valid, the slice verifies the signature information of the user equipment UE: if the verification is successful, execute (4b), otherwise, the authentication fails;

If invalid, authentication fails;

(4b) The slice negotiates the session key K with the user equipment UE, and uses the session key to encrypt and verify a successful response message, and sends it to the user equipment UE;

(5) After the user equipment UE receives the sliced response message, it uses the session key K negotiated between the two to decrypt the response message:

If the decryption is successful, the mutual authentication between the user equipment UE and the selected slice is successful;

Otherwise, authentication fails.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses a certificate-free method to generate a user signature private key, does not require certificate verification, and effectively solves the problem of complicated certificate management, certificate issuance, revocation, verification and storage requiring more resources.

2. The present invention uses a set of random numbers to encrypt the feature value of the slice, and the original feature value of the slice does not participate in the calculation, which realizes the privacy protection of the feature information of the slice and effectively prevents third-party attackers from illegally obtaining the slice information.

3. The present invention adopts the SM2 digital signature algorithm to realize mutual authentication between the user equipment UE and the slice. The signature speed is fast, the storage space is small, the overhead is low, the authentication process is simple, and it is more suitable for lightweight authentication of mass user equipment access in the industrial Internet.

Description of drawings

Figure 1 is a scene diagram of the existing industrial Internet;

Fig. 2 is the realization flowchart of the present invention.

Detailed ways

Referring to Figure 1, in the existing B5G/6G secure network slicing scenario of the industrial Internet, the main participants include: user equipment UE and network slicing. Machines, sensors, industrial instruments, virtual reality equipment, different user equipment have their own business requirements, and have different requirements for bandwidth, delay, and network functions; network slicing is multiple logically independent and virtualized on a physical network The isolated virtual network is composed of several network functions and resources abstracted from the underlying resources, meeting the different business requirements of user equipment.

This example is based on the above-mentioned B5G/6G security network slicing for the industrial Internet, and a third-party key generation center KGC and access mobile management network element AMF are added. The third-party key generation center KGC is used to select public parameters and generate system The public-private key pair generates the signature private key of the user equipment; accesses the mobile management network element AMF, and is used to determine the network slices that each user equipment is allowed to access according to the locally stored information or the subscription information from the user equipment.

Referring to Figure 2, the implementation steps of this example are as follows:

Step 1: Generate a signature private key d _uc based on the user equipment identity ID _u .

(1.1) The third-party key generation center KGC selects public parameters, specifies a large prime number p, takes a base point G whose order is n on the elliptic curve on the finite field F _p , and randomly selects a number in 1<x<n x, set system private key SK _S =x, system public key PK _S =x*G, generate system public-private key pair (PK _S , SK _S =x);

(1.2) The third-party key generation center KGC randomly selects the number y _u in 1<y _u <n, and calculates a point Y _u on the elliptic curve, hash value h _u , and signature private key d _uc :

Y _u =y _u *G

h _u ＝H(ID _u ||Y _u )

d _uc ＝y _u +SK _S *h _u

Where H() represents a one-way hash function;

(1.3) The third-party key generation center KGC sends the three parameters d _uc , Y _u , and T ₁ to the user equipment UE through a secure channel, where T ₁ is the current timestamp;

(1.4) After the user equipment UE receives the information from the third-party key generation center KGC, it first checks the validity of _T1 :

(1.4.1) Add a time stamp to the message to defend against replay attacks, the user equipment UE subtracts the received time stamp T ₁ from the current time to obtain the difference ΔT;

(1.4.2) Set the time threshold δ, and compare the difference ΔT with the time threshold δ:

If ΔT<δ, the time stamp T ₁ is valid, execute (1.5);

Otherwise, the time stamp T ₁ is invalid, and the user equipment UE does not accept the signature private key d _uc ;

(1.5) The user equipment UE verifies whether d _uc *G=Y _u +h _u *PK _S is established:

If established, the user equipment UE accepts the signature private key d _uc ;

Otherwise, the user equipment UE does not accept the signature private key d _uc ;

Step 2: The user equipment UE selects a suitable slice to access according to its own service scenario requirements.

(2.1) Divide the physical network resource PNR into l logically independent fine-grained network slices according to the characteristics of rate, throughput, bandwidth, delay, scalability, and security level. Each network slice is expressed as the following feature vector:

S _i F＝{S _i F ₁ ,S _i F ₂ ,…,S _i F _t ,…,S _i F _T }

Where i∈[1,l], S _i F _t represents the t-th eigenvalue of slice i, and T is the number of slice features;

(2.2) The user equipment UE constructs the requested slice feature vector Req according to its own business requirements:

(2.2.1) Classify business requirements according to the characteristics of speed, throughput, bandwidth, delay, scalability, and security level;

(2.2.2) Map each feature of business requirements into a slice feature value, and construct a request slice feature vector Req={x ₁ , x ₂ ,...x _t ,...x _T }, where x _t represents the request The tth eigenvalue of the slice, where T represents the number of eigenvalues of the slice;

(2.2.3) Set a group of random numbers C=(C ₁ , C ₂ ,...C _t ,...C _T ) and a randomly generated secret value f;

(2.2.4) For each eigenvalue x _t in the constructed request slice feature vector Req, use each value C _t in the random number C and the randomly generated secret value f to calculate, and obtain the encrypted request slice feature vector Req':

Req'={x ^′ _t =x _t +f*C _t ,1≤t≤T};

(2.3) Access the mobile management network element AMF to analyze the encrypted request slice feature vector Req' and the random number C, and check the slice list set that the user equipment UE is allowed to access. The list set contains m slices, and each slice can be expressed as Eigenvector w _j =(y ₁ ,y ₂ ,...y _t ,...y _T ), where y _t represents the t-th eigenvalue, and T represents the number of eigenvalues of the slice;

(2.4) Access the mobile management network element AMF to encrypt each slice in the slice list set, and calculate the encrypted slice feature vector w′ _j :

w′ _j ＝(b _j1 ,b _j2 ,b _j3 )

in

(2.5) Combine the encrypted feature vector w′ _j of each slice in the slice list set to obtain the encrypted slice list set W=(w′ ₁ ,…w′ _j ,…w′ _m ), where j∈[1 ,m];

(2.6) The access mobility management network element AMF sends the encrypted slice list W to the user equipment UE;

(2.7) After the user equipment UE receives the encrypted slice list set W, it calculates the Euclidean distance d _j between each slice feature vector w′ _j in W and the encrypted request slice feature vector Req:

E_j＝b_j1-f*b_j2；in,

E _j =b _j1 -f*b _j2 ;

(2.8) The user equipment UE selects the slice _{with the smallest} Euclidean distance dj in the slice list set as the most suitable slice selected for the user equipment UE according to service requirements.

Step 3: The user equipment UE signs the request information M based on the SM2 digital signature algorithm, and initiates and selects a slice connection request.

(3.1) The user equipment UE calculates the digest value Z _Y =H _v (Len‖ID _u ‖a‖b‖G _x ‖G _y ‖Y _x ‖Y _y ), where ID _u is the user equipment identifier, and Len represents the value of ID _u Length bit value, Y _x and Y _y represent the coordinates of a point Y _u on the elliptic curve, H _v () is a cryptographic hash function that generates a v-bit digest value;

(3.2) The user equipment UE calculates the cryptographic hash value e=H _v (Z _Y ||M);

(3.3) The user equipment UE randomly selects the number a in 1<a<n, and calculates the elliptic curve point (x ₁ , y ₁ )=aG;

(3.4) User equipment UE calculates signature information (r, s):

r=(e+x ₁ ) mod n, s=((1+d _uc ) ^-1 (ar*d _uc )) mod n,

Among them, G is the base point on the elliptic curve, n is the order of the base point G, and d _uc is the signature private key of the UE;

(3.5) The user equipment UE sends the five parameters Y _u , r, s, M, T ₂ to the selected slice, where T ₂ is the current timestamp.

Step 4: The slice verifies the request of the user equipment, and negotiates a session key with the user equipment.

(4.1) After the slice receives the five parameters _Yu , r, s, M, and T ₂ sent by the user equipment UE, it first verifies whether the timestamp T ₂ is valid, and the verification steps are the same as (1.4). If it is invalid, the authentication fails ; Otherwise, execute (4.2);

(4.2) The slice verifies the signature information of the user equipment UE:

(4.2.1) Slice test whether 1<r<n is established, if not established, the verification fails; otherwise, execute (4.2.2);

(4.2.2) Slice check whether 1<s<n is established, if not established, the verification fails; otherwise execute (4.2.3);

(4.2.3) Slice calculation password hash value e'=H _v (Z _Y ||M);

(4.2.4) slice calculation hash value h′ _u ＝H(ID _u ||Y _u );

(4.2.5) Slice calculation elliptic curve point (x′ ₁ ,y′ ₁ )=s*G+(r+s)*(Y _u +h′ _u *PK _S );

(4.2.6) Slice inspection (e′+x′ ₁ ) mod n=r is established, if established, the verification is successful; otherwise, the authentication fails.

(4.3) The slice negotiates the session key K with the user equipment UE:

(4.3.1) The user equipment UE and the slice generate and exchange data:

The user equipment UE randomly selects the number r _A in 1<r _A <n, calculates the point R _A =r _A *G=(x _A ,y _A ) on the elliptic curve, and sends the point R _A to the slice, where ( x _A , y _A ) is the coordinate value of point R _A ;

The slice randomly selects the number r _B in 1<r _B <n, calculates the point R _B =r _B *G=(x _B ,y _B ) on the elliptic curve, and sends this point R _B to the user equipment UE, where ( x _B , y _B ) is the coordinate value of point R _B ;

(4.3.2) The user equipment UE and the slice calculate their respective session keys:

After receiving the _RA sent by the user equipment UE, the slice verifies whether _RA satisfies the elliptic curve equation: if not, the key negotiation fails; otherwise, the slice takes x _A from _RA , and calculates the point V on the elliptic curve and its own The session key K _B :

V=(d _B +r _B *x _B )*(P _A +x _A *R _A )=(x _V ,y _V ),

K _B ＝KDF(x _V ||y _V ||Z _A ||Z _B , L _K ),

Among them, Z _A and Z _B are digest values, L _K is the set key length, (x _V , y _V ) is the coordinate value of point V, d _B is the private key of the slice, and _PA is the public key of the user equipment UE. key;

After receiving the _RB sent by the slice, the user equipment UE verifies whether _RB satisfies the elliptic curve equation, if not, the key negotiation fails; _{otherwise, the user equipment UE takes x B from} RB and calculates the points U and Own session key K _A :

U＝(d _A +r _A *x _A )*(P _B +x _B *R _B )＝(x _U ,y _U )

K _A ＝KDF(x _U ||y _U ||Z _A ||Z _B ,L _K )

Where (x _U , y _U ) is the coordinate value of the point U, d _A is the private key of the user equipment UE, and P _B is the public key of the slice;

(4.3.3) According to this slice and the user equipment UE, the session key is successfully calculated separately, and the session key K after the successful negotiation between the two is obtained:

K = K _A = K _B ;

(4.4) The slice uses the session key K to encrypt a successful verification response message, and sends it to the user equipment UE.

Step 5: the UE decrypts the response message.

(5.1) After receiving the response message of the slice, the user equipment UE uses the session key K negotiated between the two to decrypt the response message;

(5.2) The user equipment UE judges and selects whether the slice is authenticated successfully:

If the user equipment UE decrypts successfully, the authentication is successful;

Otherwise, authentication fails.

The above description is only a specific example of the present invention, and does not constitute any limitation to the present invention. Obviously, for those skilled in the art, after understanding the contents and principles of the present invention, it is possible without departing from the principles and structures of the present invention. Various modifications and changes in form and details are made under the circumstances of the present invention, but these modifications and changes based on the idea of the present invention are still within the protection scope of the claims of the present invention.

Claims (5)

1. A B5G/6G network slicing authentication method for the industrial Internet, comprising the following steps: (1) Generate the signature private key d _uc based on the user equipment identity ID _u : (1a) The third-party key generation center KGC selects public parameters, specifies a large prime number p, takes a base point G whose order is n on the elliptic curve on the finite field F _p , and randomly selects a number in 1<x<n x, set system private key SK _S =x, system public key PK _S =x*G, generate system public-private key pair (PK _S , SK _S =x); (1b) KGC randomly selects the number y _u in 1<y _u <n, and calculates a point Y _u =y _u *G on the elliptic curve, the hash value h _u =H(ID _u ||Y _u ), the signature private Key d _uc =y _u +SK _S *h _u , send the three parameters d _uc , Y _u , T ₁ to the user equipment UE through a secure channel, where T ₁ is the current timestamp, H() means one-way hash Xi function; (1c) After the user equipment UE receives the information from the third-party key generation center KGC, it first checks the validity of _T1 : If valid, execute (1d); If invalid, the user equipment UE does not accept the signature private key d _uc ; (1d) Verify that d _uc *G=Y _u +h _u *PK _S is established: If established, the user equipment UE accepts the signature private key d _uc ; Otherwise, the user equipment UE does not accept the signature private key d _uc ; (2) The user equipment UE selects an appropriate slice access according to its own business scenario requirements: (2a) Divide the physical network resource PNR into l logically independent fine-grained network slices according to the characteristics of rate, throughput, bandwidth, delay, scalability, and security level, and each network slice is expressed as the following feature vector: S _i F＝{S _i F ₁ ,S _i F ₂ ,…,S _i Ft,…,S _i F _T } Where i∈[1,l], S _i F _t represents the t-th eigenvalue of slice i, and T is the number of slice features; (2b) The user equipment UE constructs the requested slice feature vector according to its own service requirements, encrypts and processes the feature value of the feature vector with a random number, and initiates a slice selection request; (2c) The access mobility management network element AMF encrypts the characteristic value of each slice in the list according to the slice list set allowed by the user equipment UE and sends it to the user equipment UE; (2d) After the user equipment UE receives the encrypted slice list set, it calculates the Euclidean distance between the encrypted slice list set and the requested slice feature vector, and selects the slice with the smallest Euclidean distance in the slice list set as the slice for the user equipment UE according to the service The most suitable slice to be selected; (3) The user equipment UE initiates and selects a connection authentication request for a slice, uses a signature algorithm to sign the request information M, generates signature information (r, s), and sets five Y _u , r, s, M, T ₂ Parameters sent to the selection slice, where T ₂ is the current timestamp; (4) The slice responds to the request of the user equipment UE by verifying the signature algorithm: (4a) After receiving the request message sent by the user equipment UE, the slice first verifies whether the timestamp T ₂ is valid: If it is valid, the slice verifies the signature information of the user equipment UE: if the verification is successful, execute (4b), otherwise, the authentication fails; If invalid, authentication fails; (4b) The slice negotiates the session key K with the user equipment UE, and uses the session key to encrypt and verify a successful response message, and sends it to the user equipment UE; (5) After the user equipment UE receives the sliced response message, it uses the session key K negotiated between the two to decrypt the response message: If the decryption is successful, the mutual authentication between the user equipment UE and the selected slice is successful; Otherwise, authentication fails. 2. method according to claim 1 is characterized in that in (1c), the validity of checking T ₁ realizes as follows: Set the time threshold δ, and add a timestamp to the message to resist replay attacks. The user equipment UE uses the current time to subtract the received timestamp T ₁ to get the difference ΔT, and compares the difference ΔT with the time threshold δ: If ΔT<δ, the time stamp T ₁ is valid; Otherwise, the timestamp T ₁ is invalid. 3. The method according to claim 1, characterized in that in (2b), the user equipment UE constructs the slice feature vector of the request according to its own service requirements, and encrypts the feature value of the feature vector with a random number, and realizes as follows: (2b1) Classify business requirements according to the characteristics of speed, throughput, bandwidth, delay, scalability, and security level; (2b2) Map each feature of the business requirement into a slice feature value, construct the requested slice feature vector Req={x ₁ , x ₂ ,...x _t ,...x _T }, Among them, x _t represents the eigenvalue of the t-th requested slice, and T represents the number of eigenvalues of the slice; (2b3) Set a group of random numbers C=(C ₁ , C ₂ ,...C _t ,...C _T ) and a randomly generated secret value f; (2b4) For each eigenvalue x _t in the constructed request slice feature vector Req, use each value C _t in the random number C and the randomly generated secret value f to calculate, and obtain the encrypted request slice feature vector Req′ , Req'={x' _t =x _t +fC _t , 1≤t≤T}. 4. method according to claim 1, it is characterized in that utilize signature algorithm to sign request information M in (3), be to adopt SM2 digital signature algorithm, realize as follows: (3a) Calculate the digest value Z _Y = H _v (Len‖ID _u ‖a‖b‖G _x ‖G _y ‖Y _x ‖Y _y ), where ID _u is the user equipment identifier, and Len represents the length bit value of ID _u , Y _x and Y _y represent the coordinates of a point Y _u on the elliptic curve, and H _v () is a cryptographic hash function that generates a v-bit digest value; (3b) Calculate the cryptographic hash value e=H _v (Z _Y ||M); (3c) Randomly select the number a in 1<a<n, and calculate the elliptic curve point (x ₁ , y ₁ )=aG; (3d) Calculate signature information (r, s): r=(e+x ₁ ) mod n, s=((1+d _uc ) ^-1 (ar*d _uc )) mod n, Wherein, G is the base point on the elliptic curve, n is the order of the base point G, and d _uc is the signature private key of the user equipment UE; (3e) The user equipment UE sends the signature information (r, s) to the slice. 5. The method according to claim 1, characterized in that in (4b), the slice negotiates the session key with the user equipment UE, which is carried out by using the SM2 key exchange protocol, which is implemented as follows: (4b1) The user equipment UE and the slice generate and exchange data: The user equipment UE randomly selects the number r _A in 1<r _A <n, calculates the point R _A =r _A *G=(x _A ,y _A ) on the elliptic curve, and sends the point R _A to the slice, where ( x _A , y _A ) is the coordinate value of point R _A ; The slice randomly selects the number r _B in 1<r _B <n, calculates the point R _B =r _B *G=(x _B ,y _B ) on the elliptic curve, and sends this point R _B to the user equipment UE, where ( x _B , y _B ) is the coordinate value of point R _B ; (4b2) The user equipment UE and the slice calculate their respective session keys: After receiving the _RA sent by the user equipment UE, the slice verifies whether _RA satisfies the elliptic curve equation: if not, the key negotiation fails; otherwise, the slice takes x _A from _RA , and calculates the point V on the elliptic curve and its own The session key K _B : V=(d _B +r _B *x _B )*(P _A +x _A *R _A )=(x _V ,y _V ), K _B ＝KDF(x _V ||y _V ||Z _A ||Z _B , L _K ), Among them, Z _A and Z _B are digest values, L _K is the set key length, (x _V , y _V ) is the coordinate value of point V, d _B is the private key of the slice, and _PA is the public key of the user equipment UE. key; After receiving the _RB sent by the slice, the user equipment UE verifies whether _RB satisfies the elliptic curve equation, if not, the key negotiation fails; _{otherwise, the user equipment UE takes x B from} RB and calculates the points U and Own session key K _A : U＝(d _A +r _A *x _A )*(P _B +x _B *R _B )＝(x _U ,y _U ) K _A ＝KDF(x _U ||y _U ||Z _A ||Z _B ,L _K ) Where (x _U , y _u ) is the coordinate value of the point U, d _A is the private key of the user equipment UE, and P _B is the public key of the slice; (4b3) Calculate the session key successfully according to the slice and the user equipment UE respectively, and obtain the session key K after successful negotiation between the two: K = K _A = K _B .

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