A privacy-preserving cross-domain authentication method for large-scale heterogeneous networks

Abstract

The present invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks. This method records the user terminal's pseudonym, trust level, and protected access rights on a blockchain. Therefore, during cross-domain network access, the service network can directly authenticate the user without communicating with the user's local network. Furthermore, access rights are encrypted before being published to the blockchain, allowing only authorized service networks to access them, thus enhancing user privacy. The present invention also employs a ring signature algorithm to blend user pseudonyms and ensure a reliable association between the trust level and the new pseudonym without exposing the correlation between the old and new pseudonyms. This method, apart from the local network and the user themselves, prevents anyone from identifying the true signer of the ring signature, thereby blending the user's pseudonym and ensuring unconnectability. The present invention allows the local network to use forged users to participate in pseudonym updates, further enhancing the level of identity privacy protection.

Description

Technical Field

[0001] The present invention belongs to the field of network security technology, and in particular relates to a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks. Background Art

[0002] With the development and maturity of fifth-generation mobile communication technology (5G), more and more scholars are turning their research focus to sixth-generation mobile communication technology (6G). Although 6G is still in its infancy, as a foundational technology supporting future industries and society, it is expected to be launched in the 2030s. Some researchers have proposed that 6G is an integrated large-scale heterogeneous network (LS-HetNet), integrating different types of networks such as space satellite networks, terrestrial networks, and marine networks into a unified network system to provide anytime, anywhere networking services. Unlike homogeneous networks and traditional heterogeneous networks, 6G's large-scale heterogeneous network consists of network domains operated by different operators, with different network entities and functions. At the same time, large-scale heterogeneous networks are characterized by distribution, heterogeneity, openness, low latency, and scalability, thus enabling seamless global coverage.

[0003] The International Telecommunication Union (ITU-T) Telecommunication Standardization Sector stipulates that trust management technology should be introduced into LS-HetNet to build trusted network communications. In addition, it should support diversified authentication, not only ensuring the validity of the user (UE) based on identity, but also providing different types of personalized services to the UE based on permissions.

[0004] Although large-scale heterogeneous networks can enhance the interoperability of different types of networks, improve quality of service (QoS), and meet complex business needs, they still face serious security and privacy issues in many aspects. For example, the structure of large-scale heterogeneous networks reduces the difficulty of network access, but due to the lack of a trusted centralized entity to manage the identities and access rights of all users, additional communication overhead is introduced in cross-domain authentication. In addition, trust management in large-scale heterogeneous networks can easily conflict with user identity privacy because the trust level bound to the user pseudonym exposes the connection between the old pseudonym and the new pseudonym, hindering the update of the pseudonym. In addition, the privacy of user data (such as authentication parameters and access rights) is not effectively protected during cross-domain network access.

[0005] Blockchain is a distributed, immutable data ledger that can serve as a decentralized, trusted platform for trusted access control in large-scale heterogeneous networks. However, privacy protection remains a challenge when applying blockchain. Due to the public nature of blockchain, sensitive user data, such as user identity, access rights, and authentication parameters, recorded on the blockchain, is also publicly accessible. While traditional blockchain systems such as Bitcoin and Ethereum use pseudonyms to protect identity privacy, a careful review of historical records reveals the correlation of pseudonyms. In LS-HetNet, once the link between a user's pseudonym and their real identity is identified, their access rights and trust level are also exposed. Pseudonym updates are a viable solution to this problem. However, this conflicts with trust management, which requires user identities to remain consistent, while pseudonym changes significantly complicate trust assessment.

[0006] The Third Generation Partnership Project (3GPP) describes using local networks (HNs) to enable cross-domain communication in large-scale heterogeneous networks. While convenient and easy to implement, this approach increases access latency. Furthermore, it ignores data and identity privacy. Furthermore, it lacks support for trust management and authorization authentication.

[0007] To simplify authentication overhead, the existing literature (X. Duan and X. Wang, “Authentication handover and privacy protection in 5G hetnets using software-defined networking,” IEEE Communications Magazine, vol. 53, no. 4, pp. 28–35, 2015) proposed an efficient handover authentication scheme in large-scale heterogeneous networks with data privacy protection. This scheme uses software-defined networking (SDN) to encrypt and share user authentication parameters within the network, achieving mutual identity authentication and data privacy protection. However, this scheme focuses on encrypting user authentication parameters and does not address trust management, permission authentication, or identity privacy protection.

[0008] Considering that users frequently switch between different cellular networks in 5G heterogeneous networks managed by the same operator and require repeated authentication, the existing technical literature: A. Yazdinejad, R.M. Parzi, A. Dehghantanha, and K.-KRChoo, "Blockchain-enabled authentication handover with efficient privacy protection in SDN-based 5G networks," IEEE Transactions on Network Science and Engineering, vol. 8, no. 2, pp. 1120–1132, 2019, proposed an efficient authentication handover scheme based on blockchain and software-defined networking, and supported data privacy protection. It eliminates unnecessary re-authentication when frequently switching between heterogeneous cellular networks and protects data privacy through encryption algorithms. However, it does not consider trust management, permission authentication, and identity privacy.

[0009] To achieve efficient authentication and privacy protection in 5G heterogeneous networks, a prior art paper, J. Cao, M. Ma, Y. Fu, H. Li, and Y. Zhang, “Cppha: Capability-based privacy-protection handover authentication mechanism for SDN-based 5G hetnets,” IEEE Transactions on Dependable and Secure Computing, vol. 18, no. 3, pp. 1182–1195, 2019, proposed a handover authentication mechanism based on SDN and user capabilities. Compared with the previous scheme, this not only improves the efficiency of handover authentication but also protects identity privacy through pseudonym updates during the handover process. However, SDN technology is not suitable for the large-scale heterogeneous networks of 6G because each network domain in large-scale heterogeneous networks is managed by a different operator, making it difficult to achieve technical unification.

[0010] To achieve trusted network access and multi-faceted authentication, the existing technical literature: Z. Yan, H. Xie, P. Zhang, and BB Gupta, "Flexible data access control in D2D communications," Future Generation Computer Systems, vol. 82, pp. 738–751, 2018, proposes a flexible data access control scheme for D2D networks based on attribute encryption (ABE) and trust management. It provides identity authentication, permission authentication, and identity privacy protection.

[0011] In addition, the existing technical literature: Z. Yan, "A trust management framework for integrated networks based on blockchain," 2020, proposed a self-organizing trust management framework for large-scale heterogeneous network communications, which solved the problems of key management, identity privacy protection and trusted network access, but this solution does not support data privacy protection and permission authentication.

[0012] In summary, existing solutions do not support comprehensive authentication and privacy protection. Secondly, few solutions focus on trusted access control in large-scale heterogeneous networks. While existing technologies have proposed trust management frameworks for large-scale heterogeneous network communications, these require the support of a trusted execution environment (TEE). This hinders the scalability and versatility of large-scale heterogeneous networks, thus restricting their development. In summary, no current solution supports privacy protection and cross-domain authentication in trusted large-scale heterogeneous networks. Summary of the Invention

[0013] To address the above-mentioned problems in the prior art, the present invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0014] The present invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks, which is applied to an authentication system model. The authentication system model includes a user terminal UE, a local network HN, a service network SN, and a blockchain BC. The privacy-preserving cross-domain authentication method for large-scale heterogeneous networks includes:

[0015] During the registration phase, the user terminal UE sends a registration request to the local network HN according to the registration protocol specified by the authentication system model. The local network HN generates registration information for the user terminal UE in response to the registration request, returns the registration information to the user terminal UE, and publishes the permission information generated during the registration phase to the blockchain BC.

[0016] During the authentication phase, the user terminal UE sends an authentication request and a call request to the called user terminal UE' to the service network SN in accordance with the authentication protocol specified by the authentication system model. The service network SN performs identity authentication and authority authentication based on the authority information stored in the blockchain BC and the registration information stored in the user terminal UE. The called user terminal UE' performs authority authentication on the user terminal UE based on the authority information stored in the blockchain BC. After the authentication is successful, a session is established between the user terminal UE and the called user terminal UE' in response to the call request.

[0017] In the pseudonym update phase, the user terminal UE initiates a pseudonym update request to the local network HN according to the pseudonym update protocol specified by the authentication system model, or the local network HN initiates a pseudonym update request regularly according to the pseudonym update protocol, and the local network HN performs the pseudonym update;

[0018] In the privacy enhancement phase, the local network HN generates fake user terminals UEs and corresponding registration information, receives privacy enhancement requests from all user terminals, performs the pseudonym update process, publishes the updated permission information of all user terminals to the blockchain BC, and feeds back the registration information of the real user terminals to the user terminals UE.

[0019] Beneficial effects of the present invention:

[0020] The present invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks, designed to support trusted access control in large-scale, blockchain-based heterogeneous networks. This method records the user terminal's pseudonym, trust level, and protected access rights on the blockchain. Therefore, during cross-domain access, the service network can directly authenticate the user without communicating with the user's local network. Furthermore, access rights are encrypted before being published to the blockchain, ensuring access only to authorized service networks, thus enhancing user privacy. To address the conflict between trust management and pseudonym updates, the present invention employs a ring signature algorithm to blend user pseudonyms and ensure a reliable association between trust level and new pseudonym without exposing the correlation between the old and new pseudonyms. The true signer of the ring signature is unidentifiable except for the local network and the user, thereby blending the user's pseudonym and ensuring unlinkability. More importantly, the present invention allows the local network to participate in anonymous updates using forged pseudonyms, further enhancing identity privacy protection. Furthermore, pseudonym updates can be initiated in real time by the user or periodically by the local network, ensuring the flexibility and practicality of the present invention. The present invention will be further described in detail below with reference to the accompanying figures and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of an authentication system model provided by an embodiment of the present invention;

[0022] Figure 2 This is a process diagram of a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0024] The present invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks, which is applied to authentication system models such as Figure 1 As shown, the authentication system model includes the user terminal UE, the local network HN, the service network SN, and the blockchain BC.

[0025] Refer to Table 1, which records the symbols and meanings used in the present invention.

[0026] Table 1 Symbols and meanings

[0027]

[0028]

[0029] Among them, the user terminal UE is a device used by users in large-scale heterogeneous networks. It contains a universal identity module UIM that stores information related to the terminal's valid identity and access rights. The local network HN is a network domain maintained by an independent operator. It is responsible for user terminal registration, identity management, pseudonym update and access rights management. Each user terminal needs to submit its real identity ID UE Initiate a registration request to the local network to obtain the public and private key pair (pk UE ,sk UE ), validity endorsement And the access permission list AL UE AL UE It includes a series of different access rights, such as SMS permission and video permission. The service network SN is also an independent network domain, which is responsible for providing roaming services to user terminals when they move out of the local network coverage. The blockchain system BC is responsible for recording and sharing the anonymous identity pk of user terminals in all network domains. UE , Trust Level TV UE , encrypted access rights token UE And pseudonym update information, that is, the new public key pk' UE 、New access token' UE and ring signature σ UEThe blockchain in a large-scale heterogeneous network is a consortium chain system maintained by a series of miners from different network domains.

[0030] This invention assumes that all network domains are operated by independent operators, and a service agreement will be reached between the local network and the service network to generate a reliability endorsement. A secure communication channel is established. Furthermore, after registering with the HN, a reliable communication channel is established between the UE and the HN. However, there is no secure communication channel between the UE and the SN, or between individual UEs. Therefore, identity authentication is required before cross-domain communication. This invention includes four protocols: a registration protocol, an authentication protocol, a pseudonym update protocol, and a privacy enhancement protocol.

[0031] like Figure 2 As shown, the present invention provides a privacy-preserving and efficient cross-domain authentication method for large-scale heterogeneous networks, including:

[0032] During the registration phase, the user terminal UE sends a registration request to the local network HN according to the registration protocol specified by the authentication system model. The local network HN generates registration information for the user terminal UE in response to the registration request, returns the registration information to the user terminal UE, and publishes the permission information generated during the registration phase to the blockchain BC.

[0033] The registration protocol specifies the real identity sent by the user terminal UE to the local network HN, the private key pair obtained from the local network HN, the corresponding access rights and the trust level.

[0034] During the authentication phase, the user terminal UE sends an authentication request and a call request to the called user terminal UE' to the service network SN in accordance with the authentication protocol specified by the authentication system model. The service network SN performs identity authentication and authority authentication based on the authority information stored in the blockchain BC and the registration information stored in the user terminal UE. The called user terminal UE' performs authority authentication on the user terminal UE based on the authority information stored in the blockchain BC. After the authentication is successful, a session is established between the user terminal UE and the called user terminal UE' in response to the call request.

[0035] The authentication protocol specifies that the user terminal UE and the service network SN use a two-way identity authentication and authority authentication method, as well as the sources of authentication information and authority information of the user terminal UE, the service network SN, and the called user terminal.

[0036] In the pseudonym update phase, the user terminal UE initiates a pseudonym update request to the local network HN according to the pseudonym update protocol, or the local network HN initiates a scheduled pseudonym update according to the pseudonym update protocol, and the local network HN performs the pseudonym update;

[0037] In the privacy enhancement phase, the local network HN generates fake user terminals UEs and corresponding registration information, receives privacy enhancement requests from user terminals, performs pseudonym update, publishes the updated permission information of all user terminals to the blockchain BC, and feeds back the new registration information of the real user terminals to the user terminals UE.

[0038] This invention provides a privacy-preserving cross-domain authentication method for large-scale heterogeneous networks, designed to support trusted access control in large-scale, blockchain-based heterogeneous networks. This method records the user terminal's pseudonym, trust level, and protected access rights on a blockchain. Therefore, during cross-domain access, the service network can directly authenticate the user without communicating with the user's local network. Furthermore, access rights are encrypted before being published to the blockchain, ensuring access only to authorized service networks, thus enhancing user privacy. To address the conflict between trust management and pseudonym updates, this invention employs a ring signature algorithm to blend user pseudonyms and ensure a reliable association between trust level and new pseudonym without exposing the correlation between the old and new pseudonyms. The true signer of the ring signature is unidentifiable except for the local network and the user, thereby blending the user's pseudonym and ensuring unlinkability. More importantly, this invention allows the local network to participate in anonymous updates using forged pseudonyms, further enhancing identity privacy protection. Furthermore, pseudonym updates can be initiated in real time by the user or periodically by the local network, ensuring the flexibility and practicality of this invention.

[0039] As an optional embodiment of the present invention, the user terminal UE sends a registration request to the local network HN according to the registration protocol specified by the authentication system model during the registration phase. The local network HN generates registration information for the user terminal UE in response to the registration request and returns it to the user terminal UE, including:

[0040] During the registration phase, the user terminal UE sends its real identity ID to the local network HN. UE And access permission request (AL UE );

[0041] The local network HN receives the real identity id UE And access permission request (AL UE ) after generating a public-private key pair (pk UE ,sk UE ), validity endorsement sign HN (pk UE ), using the generated random number r∈Z n Access permission list AL for user terminals UE Encrypt and generate access token And the public key pk of the user terminal UE UE Assign an initial trust value TV0;

[0042] The local network HN sends the public-private key pair (pk UE ,sk UE ) Validity endorsement sign HN (pk UE ), Access Rights List AL UE And the random number r is sent to the user terminal UE through a secure channel as registration information; the public key pk UE As the anonymous identity of the user terminal UE, the local network HN publishes the anonymous identity, access permission token Token and initial trust value TV0 as permission information on the blockchain BC.

[0043] See the registration agreement process below:

[0044]

[0045] As an optional embodiment of the present invention, in the authentication phase, the user terminal UE sends an authentication request and a call request for calling the called user terminal UE' to the service network SN in accordance with the authentication protocol specified by the authentication system model; the service network SN performs identity authentication and authority authentication in combination with the authority information stored in the blockchain BC and the registration information stored in the user terminal UE, and the called user terminal UE' performs authority authentication on the user terminal UE in combination with the authority information stored in the blockchain BC. After the authentication is passed, establishing a session for the user terminal UE and the called user terminal UE' in response to the call request includes:

[0046] In the authentication phase, the user terminal UE that sends the call request is the calling user terminal. The calling user terminal UE sends an authentication request Request (M auth );

[0047] The authentication request includes the public key pk UE And the public key pk of the local network HN HN ;

[0048] The service network SN responds to the authentication request Request(M auth ), send the service network identity ID to the calling user terminal UE SN , the public key pk of the service network SN And the local network endorses the reliability of the service network

[0049] Calling user terminal UE verification reliability endorsement The correctness of the service network SN is based on the correct premise of using the public key pk SN, encrypt the validity endorsement in sequence Access Rights List AL UE , random number r and public key pk of the called user terminal UE' UE 'Encrypt to obtain encrypted information, and use the private key sk of the calling user terminal UE UE Sign the summary of the encrypted message, and send the encrypted message, the signature of the summary, and the public key pk of the called user terminal to the UE 'The call request is sent to the service network SN;

[0050] Service network SN endorses validity Verify and obtain the access permission token Token from the blockchain BC and verify the access permission list AL UE validity; endorsement of validity And the access permission list AL UE After all verifications are passed, a key negotiation request M is generated. agree and sent to the called user terminal UE' through the local network of the called user terminal UE';

[0051] The called user terminal UE' obtains the trust value of the calling user terminal UE on the blockchain BC, verifies whether the trust value meets the call request of the called user terminal UE', and if so, negotiates a session key with the calling user terminal UE.

[0052] When a roaming calling terminal UE wants to communicate with a called terminal UE', it should first execute an authentication protocol. In the authentication protocol, the UE and the SN perform a two-way identity authentication using a signature algorithm. In addition, the SN and the UE' use the permission list and trust value recorded on the blockchain to perform permission authentication on the UE. For details, see the following authentication protocol:

[0053]

[0054] As an optional embodiment of the present invention, in the pseudonym update phase, the user terminal UE initiates a pseudonym update to the local network HN according to the pseudonym update protocol specified by the authentication system model, including:

[0055] In the pseudonym update phase, the user terminal UE generates an update message M upd , and update the message M upd Send to the home network HN via the service network SN;

[0056] The update message includes the public key pk of the user terminal UE UE , update request Encrypted update time t update And a signature for the update time;

[0057] Or the local network HN initiates a scheduled pseudonym update according to the pseudonym update protocol, including:

[0058] The local network HN sends an update query to the user terminal UE through the service network SN

[0059] The user terminal UE receives the update query Generate update response R upd and sent to the local network HN via the service network SN;

[0060] Among them, the update response R upd Include update request And the public key pk of the user terminal UE UE ;

[0061] The local network HN performs pseudonym update. The pseudonym update phase includes:

[0062] The local network HN will update the request And the public key pk of the user terminal UE UE Published on the blockchain BC, waiting for the trust value of the user terminal UE to be updated on the blockchain BC, and suspending the public key pk of the user terminal UE after the trust value is updated UE Use, obtain N pseudonyms with the same trust value as the user terminal UE from the blockchain BC to form a public key set

[0063] The local network HN sends the private key sk of the user terminal UE to UE and a collection of public keys Generate ring signature σ UE , and generate a new public-private key pair (pk' UE ,sk' UE ) as a new pseudonym for the user terminal UE;

[0064] Among them, the trust value corresponding to the new pseudonym is TV UE ;

[0065] The local network HN endorses the validity of the new pseudonym generation And choose a random number r'∈Z n Access permission list AL for user terminals UE UE Encrypt and generate a new access token The new pseudonym, ring signature σ UE And the new access token Token' is published on the blockchain BC, and the new public-private key pair (pk' UE ,sk' UE ), random number r', validity endorsement By using the old public key pk UEEncrypted, and then sent to the user terminal UE, so that the user terminal UE uses the new public-private key pair (pk' UE ,sk' UE ) for communication.

[0066] This generates a new pseudonym for the user terminal and associates it with a trust value. Pseudonym updates can be initiated in real time by the user terminal or periodically by the local network. The specific process is as follows. The protocol includes pseudonym updates initiated by the UE and pseudonym updates initiated by the HN:

[0067]

[0068] As an optional embodiment of the present invention, in the privacy enhancement phase, the local network HN generates fake user terminals UEs and corresponding registration information, receives privacy enhancement requests from all user terminals, performs a pseudonym update process, publishes the updated permission information of all user terminals to the blockchain BC, and feeds back the registration information of the real user terminals to the user terminals UE, including:

[0069] In the privacy enhancement phase, the local network HN generates M fake user terminals UEs and generates a public-private key pair (PK i ,SK i ) Validity endorsement And access token Token i ;

[0070] Where, i∈[1,M];

[0071] The local network HN trains the trust values ​​of the fake user terminals UEs to make them uniformly distributed and generates update requests for the fake user terminals UEs Update request for real user terminal UE and Privacy Enhancement Requests To request the local network HN to perform the pseudonym update process to add K false pseudonyms when the pseudonym is updated, where k∈[1,K];

[0072] According to the pseudonym update protocol, the local network HN is generated for the real user (pk' UE ,sk' UE ),σ UE , and access rights token Token', and generate a new public-private key pair (PK' for each fake user terminal UEs k ,SK' k ), Ring signature σ k , access token Token' kThe local network publishes the new pseudonyms, ring signatures, and new access rights tokens of all user terminals on the blockchain BC, and sends the new public-private key pair, random value, and validity endorsement of the real user terminal UE to the real user terminal UE via the service network SN.

[0073] If only a small number of user terminals in the system participate in pseudonym updates, the size of the public key set is insufficient to protect the identity privacy of the user terminals. To this end, HN can improve the unconnectability by forging user terminals. The specific process of the privacy enhancement protocol is as follows:

[0074]

[0075] The present invention is described below through examples.

[0076] Example 1

[0077] This embodiment uses the ECC algorithm for encryption and decryption, signing, and verification, and uses the TRS ring signature algorithm for ring signature generation and verification.

[0078] In the registration protocol, pseudonym update protocol, and privacy enhancement protocol, the HN generates a public-private key pair for the UE as follows:

[0079] (1) Generate system parameters (F q ,E,a,b,n,G), where F q is a finite field, E is F q where a and b are coefficients of the elliptic curve E, l is a large prime number, and G is a point of rank n on the elliptic curve G.

[0080] (2) Randomly select sk UE ∈[1,l-1], calculate pk UE =sk UE G.

[0081] In the registration protocol, authentication protocol, pseudonym update protocol, and privacy enhancement protocol, the validity endorsement and reliability endorsement generation methods are as follows:

[0082] (1) For the signed message m, such as the public key pk of the user terminal in the validity endorsement VE And the public key pk of the reliability endorsement service network UE , calculate h=H(m).

[0083] (2) Randomly select k∈[1,l-1] and calculate (x,y)=kG.

[0084] (3) Calculate r = x (mod n). If r = 0, reselect the random number k.

[0085] (4) Calculate s = k-1 (h+sk HN r)(mod l), the endorsement information is (r,s).

[0086] The verification method is as follows:

[0087] (1) Calculate w = s -1 mod n

[0088] (2) Calculate u1 = ew, u2 = rw

[0089] (3) Calculate X = u1G + u2pk HN , v = X x (mod l)

[0090] The verification succeeds if and only if v=r.

[0091] In the authentication protocol, pseudonym update protocol, and privacy enhancement protocol, the methods for encrypting and decrypting messages are as follows:

[0092] Encryption: Randomly select r∈[1,l-1], for message m, generate ciphertext C=(rG,m+r·pk);

[0093] Decryption: m+rG-sk(rG)=m.

[0094] In the pseudonym update protocol and the privacy enhancement protocol, for the user terminal UE π , HN generates a ring signature as follows:

[0095] (1) Select a public key set

[0096] (2) Calculate the secret key image Among them H p is a hash function that returns the value of the elliptic curve F q A point on top.

[0097] (3) Generate a random number α∈Z l ,r u ∈Z l , where u∈[1,N] and u≠π;

[0098] (4) Generate L π =αG, Among them H n is a hash function that maps integers to [0, l-1].

[0099] (5) Calculation in u=π+1,π+2,…,N,1,2…π-1.

[0100] (6) Calculation The signed message is

[0101]

[0102] The method for the called UE to verify the ring signature is:

[0103] (1) Obtaining a signed message from the blockchain

[0104] (2) Calculation

[0105] (3) If c'1 = c1, the verification is successful, indicating that the trust value of the calling UE is

[0106] Example 2:

[0107] This embodiment uses the ElGamal algorithm for encryption and decryption, signing, and verification, and uses the ETRS ring signature algorithm for ring signature generation and verification.

[0108] In the registration protocol, pseudonym update protocol, and privacy enhancement protocol, the HN generates a public-private key pair for the UE as follows:

[0109] (1) Randomly select a large prime number p, select g∈(1,p),x∈(1,p-1), and calculate y=g x modp;

[0110] (2)sk UE =x,pk UE =y

[0111] In the registration protocol, authentication protocol, pseudonym update protocol, and privacy enhancement protocol, the validity endorsement and reliability endorsement generation methods are as follows:

[0112] (1) For the signed message m, such as the public key pk of the user terminal in the validity endorsement UE And the public key pk of the reliability endorsement service network SN , calculate h=H(m).

[0113] (2) Select a random number k∈(0,p-1) such that gcd(k,p-1)=1.

[0114] (3) Calculate s = (h - sk HN r)k -1 (mod(p-1)), the endorsement message is (r,s).

[0115] If and only if pk HN r r s =g H(m)(modp), the verification succeeds.

[0116] In the authentication protocol, pseudonym update protocol, and privacy enhancement protocol, the methods for encrypting and decrypting a message (m) are as follows:

[0117] encryption:

[0118] (1) Select a random number k∈(0,p-1) such that gcd(k,p-1)=1.

[0119] (2) Calculate y1 = g k (mod p).

[0120] (3) Calculate y2 = m·pk k (modp).

[0121] (4) Ciphertext C = y1||y2.

[0122] Decryption: m = y2 / y1 sk .

[0123] In the pseudonym update protocol and the privacy enhancement protocol, for the user terminal UE π , HN generates a ring signature as follows:

[0124] (1) Randomly select a∈Z q ,spk∈Z q , calculate u1=g a ,h1=H1(u1),

[0125] c1=H2(u1,x1,v1,pk HN ), r=a+c1·spk, psk=(x1,c1,r), Ring Key

[0126] (2) Regarding messages calculate h2=H1(u2), c"1=c1·f, , the final generated signature is σ=(u”1,c”1,c2,x2,y);

[0127] The method for the called UE to verify the ring signature is:

[0128] (1) Obtaining a signed message from the blockchain

[0129] (2) Calculation

[0130]

[0131] (3) If c'2 = c2, the verification is successful, indicating that the trust value of the calling UE is

[0132] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0133] Although the present application is described herein with reference to various embodiments, those skilled in the art will be able to understand and implement other variations of the disclosed embodiments in practicing the claimed application by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality.

[0134] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A privacy-preserving cross-domain authentication method for large-scale heterogeneous networks, characterized in that: Applied to an authentication system model, the authentication system model includes a user terminal (UE), a home network (HN), a service network (SN), and a blockchain (BC). The privacy-preserving cross-domain authentication method for large-scale heterogeneous networks includes: During the registration phase, the user terminal (UE) sends a registration request to the local network (HN) in accordance with the registration protocol specified by the authentication system model; the local network (HN) generates registration information for the user terminal (UE) in response to the registration request, returns the registration information to the user terminal (UE), and publishes the permission information generated during the registration phase to the blockchain (BC); During the authentication phase, the user terminal (UE) sends an authentication request and a call request to the called user terminal (UE') to the service network (SN) in accordance with the authentication protocol specified by the authentication system model; the service network (SN) performs identity authentication and authority authentication in combination with the authority information stored in the blockchain (BC) and the registration information stored in the user terminal (UE); the called user terminal (UE') performs authority authentication on the user terminal (UE) in combination with the authority information stored in the blockchain (BC); after the authentication is passed, a session is established between the user terminal (UE) and the called user terminal (UE') in response to the call request; In the pseudonym update phase, the user terminal (UE) initiates a pseudonym update request to the local network (HN) according to the pseudonym update protocol specified by the authentication system model, or the local network (HN) periodically initiates a pseudonym update request according to the pseudonym update protocol, and the local network (HN) performs the pseudonym update; In the privacy enhancement phase, the local network (HN) generates fake user terminals (UEs) and corresponding registration information, receives privacy enhancement requests from all user terminals, performs pseudonym update, publishes the updated permission information of all user terminals to the blockchain (BC), and feeds back the registration information of the real user terminals to the user terminals (UE); The registration protocol specifies the real identity sent by the user terminal (UE) to the home network (HN), the private key pair obtained from the home network (HN), the corresponding access rights and trust level; The user terminal (UE) sends a registration request to the local network (HN) according to the registration protocol specified by the authentication system model during the registration phase, and the local network (HN) generates registration information for the user terminal (UE) in response to the registration request and returns it to the user terminal (UE), including: During the registration phase, the user terminal (UE) sends its real identity ID to the home network (HN). UE And access permission request (AL UE ); The local network (HN) receives the real identity id UE After the access permission request (AL) is received, a public-private key pair (pk UE ,sk UE ), validity endorsement sign HN (pk UE ), using the generated random number r∈Z n Access permission list AL for user terminals UE Encrypt and generate access token and the public key pk of the user terminal (UE) UE Assign an initial trust value TV0; The local network (HN) sends the public-private key pair (pk UE ,sk UE ) Validity endorsement sign HN (pk UE ), Access Rights List AL UE And the random number r is sent to the user terminal (UE) through a secure channel as registration information; the public key pk UE As the anonymous identity of the user terminal (UE), the local network (HN) publishes the anonymous identity, the access permission token Token and the initial trust value TV0 as permission information on the blockchain (BC); The authentication protocol specifies that the user terminal (UE) and the service network (SN) perform bidirectional identity authentication and authority authentication, as well as the sources of authentication information and authority information of the user terminal (UE), the service network (SN), and the called user terminal; In the authentication phase, the user terminal (UE) sends an authentication request and a call request for calling the called user terminal (UE') to the service network (SN) in accordance with the authentication protocol specified by the authentication system model; the service network (SN) performs identity authentication and authority authentication in combination with the authority information stored in the blockchain (BC) and the registration information stored in the user terminal (UE); the called user terminal (UE') performs authority authentication on the user terminal (UE) in combination with the authority information stored in the blockchain (BC); after the authentication is passed, establishing a session for the user terminal (UE) and the called user terminal (UE') in response to the call request includes: In the authentication phase, the user terminal (UE) that sends the call request is the calling user terminal (UE), and the calling user terminal (UE) sends an authentication request (Request) to the service network (SN). auth ); The authentication request includes the public key pk UE and the public key pk of the local network (HN) HN ; The service network (SN) responds to the authentication request (Request) auth ), sending the service network identity ID to the calling user terminal (UE) SN , the public key pk of the service network SN And the local network endorses the reliability of the service network The calling user terminal (UE) verifies the authenticity endorsement The correctness of the service network (SN) is verified by using the public key pk SN , encrypt the validity endorsement in sequence Access Rights List AL UE , random number r and the public key pk of the called user terminal (UE') UE 'Encrypt to obtain encrypted information and use the private key sk of the calling user terminal (UE) UE Sign the summary of the encrypted message, and send the encrypted message, the signature of the summary, and the public key pk of the called user terminal to the UE 'The call request is sent to the service network (SN); The Service Network (SN) endorses the validity Verify and obtain the access rights token Token from the blockchain (BC) to verify the access rights list AL UE validity; endorsement of validity and the access permission list AL UE After all verifications are passed, a key negotiation request M is generated. agree and sent to the called user terminal (UE') through the local network of the called user terminal (UE'); The called user terminal (UE') obtains the trust value of the calling user terminal (UE) and the ring signature generated by the private key on the blockchain (BC), verifies whether the trust value meets the call request of the called user terminal (UE'), and if so, negotiates a session key with the calling user terminal (UE); In the pseudonym update phase, the user terminal (UE) initiates a pseudonym update request to the home network (HN) according to the pseudonym update protocol specified by the authentication system model, including: In the pseudonym update phase, the user terminal (UE) generates an update message M upd , the update message M upd Sending to the home network (HN) via the service network (SN); The update message includes the public key pk of the user terminal (UE) UE , update request Encrypted update time t update And a signature for the update time; The home network (HN) periodically initiating a pseudonym update request according to the pseudonym update protocol includes: The home network (HN) sends an update query to the user terminal (UE) via the service network (SN) The user terminal (UE) receives the update query Generate update response R upd and sending it to the home network (HN) through the service network (SN); Wherein, the update response R upd Include update request and the public key pk of the user terminal (UE) UE ; The home network (HN) performs pseudonym update. The pseudonym update phase includes: The home network (HN) sends the update request and the public key pk of the user terminal (UE) UE Published on the blockchain (BC), waiting for the trust value of the user terminal (UE) to be updated on the new blockchain (BC), the public key pk of the user terminal (UE) after the trust value is updated UE Use, obtain N pseudonyms with the same trust value as the user terminal (UE) from the blockchain (BC) to form a public key set The local network (HN) sends the private key sk of the user terminal (UE) UE And the public key set Generate ring signature σ UE , and generate a new public-private key pair (pk' UE ,sk' UE ) as a new pseudonym for the user terminal (UE); Among them, the trust value corresponding to the new pseudonym is TV UE ; The local network (HN) generates a validity endorsement for the new pseudonym And choose a random number r'∈Z n Access rights list AL for user terminals (UEs) UE Encrypt and generate a new access token The new pseudonym and the ring signature σ UE And the new access permission token Token' is published on the blockchain (BC), and the new public-private key pair (pk' UE ,sk' UE ), random number r', validity endorsement Through the old public key pk UE Encrypted, and then sent to the user terminal (UE) so that the user terminal (UE) uses the new public-private key pair (pk' UE ,sk' UE ) for communication.

2. A privacy-preserving cross-domain authentication method for large-scale heterogeneous networks according to claim 1, characterized in that: In the privacy enhancement phase, the local network (HN) generates fake user terminals (UEs) and corresponding registration information, receives privacy enhancement requests from all user terminals, performs a pseudonym update process, publishes the updated permission information of all user terminals to the blockchain (BC), and feeds back the registration information of the real user terminals to the user terminals (UE), including: In the privacy enhancement phase, the local network (HN) generates M fake user terminals (UEs) and generates a public-private key pair (PK i ,SK i ) Validity endorsement And access token Token i ; Where, i∈[1,M]; The local network (HN) trains the trust values ​​of the fake user terminals (UEs) to make them uniformly distributed and generates update requests for the fake user terminals (UEs) Update request (pk UE ,sign skUE (M update )) and Privacy Enhancement Requests Requesting the home network (HN) to perform a pseudonym update process to add K false pseudonyms when the pseudonym is updated; Where k∈[1,K]; According to the pseudonym update protocol, the local network (HN) generates (pk' UE ,sk' UE ),σ UE , and access rights token Token', and generate a new public-private key pair (PK' for each fake user terminal (UEs) k ,SK' k ), Ring signature σ k , access token Token' k The local network publishes the new pseudonyms, ring signatures and new access rights tokens of all user terminals on the blockchain (BC), and sends the new public-private key pair, random value and validity endorsement of the real user terminal (UE) to the real user terminal (UE) via the service network (SN).

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