A smart meter security access method and system based on ECC accumulator

Abstract

The present invention discloses a smart meter security access method and system based on ECC accumulator, which belongs to the field of network security technology. It generates anonymous identity identification for trusted smart meters and issues anonymous identity credentials to achieve anonymous and secure access. For smart meters with abnormal behavior, administrators can revoke their anonymous identity credentials. The identity of smart meters is hidden by relying on the anti-collision property of hash functions. It is difficult for hackers to forge the anonymous identity credentials of smart meters by relying on the security of ECC accumulator technology. The present invention realizes anonymous authentication of trusted smart meters and secure revocation of untrusted devices, which can improve the access security of smart meters and facilitate application in actual scenarios.

Description

Technical Field

[0001] The present invention belongs to the technical field of network security, and in particular relates to a smart meter security access method and system based on an ECC accumulator. Background Art

[0002] The power industry is a solid foundation for my country's economic and social development. Smart grid is regarded as the next generation of energy supply network. With intelligent electronic equipment, advanced information technology and two-way communication network system, it has comprehensively improved the stability, flexibility and reliability of my country's power grid system. Under the smart grid system, electricity is stably and efficiently transmitted from generators to household appliances. The management center can adjust the power generation according to the real-time request of the user's smart meter, which not only meets the user's electricity demand, but also effectively avoids over-generation. As an important part of the smart grid, the smart meter is responsible for regularly monitoring the user's electricity usage and sending the request information to the management center in real time. It is the basis for the power grid to realize information integration and digital management and control. However, in order to ensure that the electricity request information comes from a valid user and prevent other malicious devices from accessing the management center, the identity of the smart meter must be securely verified. On the other hand, by analyzing the electricity consumption data in the smart meter, the user's electricity consumption pattern can be revealed, which poses a great threat to the user's privacy security. Therefore, appropriate privacy protection mechanisms must be adopted.

[0003] The security access authentication mechanism of smart meters is the first line of defense of the smart grid security protection system. At present, there are mainly authentication methods based on passwords and certificates. Password-based authentication methods include static passwords and dynamic passwords. Static password-based authentication methods are simple to operate but have low security. Dynamic password-based authentication methods have high requirements on network status and communication capabilities and are not suitable for smart meters distributed in remote suburbs. Certificate-based authentication methods have now formed a relatively mature authentication system. The certificate authority uniformly issues digital certificates to all smart meters, and smart meters can access the management platform with valid digital certificates. Although certificate-based authentication methods have greatly improved the security of access authentication, the storage and communication overhead caused by the generation, distribution, update and revocation of certificates has placed a heavy burden on resource-constrained smart meter devices. Certificate-based authentication methods also do not achieve privacy protection of device identities. Therefore, how to use lightweight technology to achieve secure access and revocation of smart meters is an urgent problem to be solved.

[0004] Cryptographic accumulator is an efficient technology for implementing membership proof. It can hash all members of a set into a short value and generate a short evidence for each member. Members can use the corresponding evidence to prove that they belong to the set. Accumulators have quasi-commutativity and evidence unforgeability. Quasi-commutativity makes the accumulated value independent of the order of accumulated members. Evidence unforgeability ensures that it is computationally difficult for members outside the set to forge evidence to prove that they belong to the set, thereby providing security for membership proof. The accumulator administrator only needs to store the private key and a short accumulated value, without having to store the member list, and the overhead required for membership proof is linearly independent of the number of members. For a large number of smart meters, storage overhead and communication overhead are greatly reduced.

[0005] At present, a variety of accumulators with different properties and functions have been proposed, including static accumulators, dynamic accumulators, and general accumulators. Dynamic accumulators support the dynamic addition and deletion of members, and can update the evidence of existing members, which is consistent with the need for smart meter devices to add and revoke. Dynamic accumulators mainly form RSA accumulators based on strong RSA assumptions, ECC accumulators based on q-SDH assumptions, and accumulators based on Merkle trees. ECC dynamic accumulators meet the security and functionality of accumulators while having lower computational overhead, and are suitable for smart meter devices with limited computing resources. Summary of the invention

[0006] To overcome the above-mentioned defects, the present invention provides a smart meter security access method and system based on ECC accumulator, which allows the device management center to implement trusted authentication and secure revocation of the smart meter, reducing the storage, communication and other overheads of the device. At the same time, the mechanism can effectively protect the identity information of the smart meter and realize anonymous access authentication.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for secure access to a smart meter based on an ECC accumulator is based on a system comprising a device management center and a smart meter connected via a communication channel. The method comprises the following steps:

[0009] 1) The device management center initializes and generates relevant security parameters and tuples; then, after receiving the registration application of the smart meter, the device management center first calls the hash algorithm to generate the anonymous identity of the smart meter, and then calls the ECC accumulator member addition algorithm to generate an anonymous identity credential for the smart meter and update the current accumulated value;

[0010] 2) During authentication, the smart meter applies for access authentication to the device management center with the anonymous identity identifier and anonymous identity credential. The device management center calls the ECC accumulator member verification algorithm for calculation verification. If the verification passes, the authentication is successful and the smart meter is allowed to access. Otherwise, the authentication fails.

[0011] 3) For smart meters that fail authentication or behave abnormally, the device management center detects the smart meter. If the smart meter is attacked or tampered with, the device management center calls the ECC accumulator member deletion algorithm to revoke the anonymous identity credentials of the smart meter.

[0012] Furthermore, in step 1), the step of initializing and generating relevant security parameters and tuples by the device management center includes:

[0013] Select the security parameter l and use the bilinear pairing generator BPG to generate the tuple t = (p, G1, G M ,e,P) and private key Where p is a prime number of length l, G1 is a cyclic additive group of order p, G M is a multiplication group of order p, a bilinear map e:G1×G M →G M , P is the generator of G1, is the set of all numbers less than p and coprime to p, and R represents a randomly selected number from the set;

[0014] Compute the tuple t′=(P,sP,…,s q P), where q is the upper limit of the elements accumulated by the accumulator; define two functions (f, g) in the tuple t, t′: f:Z p ×Z P →Z P , and g:Z p →G1, u∈Z p .

[0015] Furthermore, in step 1), the elements to be accumulated are accumulated to obtain an accumulated value, wherein the domain of the elements to be accumulated is Z P \{-s}, the domain of the accumulated value is G1; the function of the hash algorithm is h:{0,1} * →Z P \{-s}.

[0016] Furthermore, in step 1), the device management center calculates the anonymous identity ID of the smart meter based on its unique identity ID * =h(ID); judge ID *Does it belong to the set X? If so, the identity ID has been registered. Otherwise, call the ECC accumulator member addition algorithm to add the anonymous identity of the smart meter to the current member set X = {x1,…,x k}, where x is the anonymous identity identifier of the registered smart meter, and generates the anonymous identity credential W=A of the smart meter, where A is the current accumulated value.

[0017] Furthermore, the algorithm for adding ECC accumulator members in step 1) is: A′=g(f(u,X∪{ID *}))=(ID * +s)A; where A′ is the updated accumulated value.

[0018] Furthermore, in step 1), when a new smart meter is registered, the anonymous identity credentials of other smart meters are updated to W′=A+(inf add -ID * )W, where inf add Indicates the added anonymous identity;

[0019] Further, in step 2), the device management center calls the ECC accumulator member verification algorithm to perform calculation verification, which means: calling the ECC accumulator member verification algorithm to calculate (ID * +s)W, and determine whether it is equal to A′.

[0020] Furthermore, the ECC accumulator member deletion algorithm in step 3) is: V′=g(f(u,X\{ID *}))=1 / (ID * +s)A, where V′ is the updated accumulated value.

[0021] Furthermore, in step 3), when a smart meter is revoked, the anonymous identity credentials of other smart meters are updated to W′=(1 / (inf del -ID * ))(WA′), where inf del Represents a revoked anonymous identity.

[0022] A smart meter security access system based on an ECC accumulator includes a device management center and a smart meter connected through a communication channel, wherein:

[0023] The device management center is used to aggregate user electricity consumption data and is responsible for the access management of smart meters, including the issuance, authentication and revocation of anonymous identity credentials;

[0024] Smart meters are used to regularly monitor users' electricity usage behavior and transmit the collected data to the device management center after anonymous authentication. When the anonymous identity credentials are revoked, the authentication fails and access to the device management center cannot be made again.

[0025] The present invention generates anonymous identity identification for trusted smart meters and issues anonymous identity credentials to achieve anonymous and secure access; for smart meters with abnormal behavior, administrators can revoke their anonymous identity credentials; relying on the anti-collision property of hash functions, the identity of smart meters is hidden; relying on the security of ECC accumulator technology, it is difficult for hackers to forge the anonymous identity credentials of smart meters. The present invention realizes anonymous authentication of trusted smart meters and secure revocation of untrusted devices, which can improve the access security of smart meters and facilitate application in actual scenarios.

[0026] The following analyzes the characteristics and advantages of this mechanism compared with existing solutions from the aspects of security and performance:

[0027] In the above process, the anonymous identity of the smart meter is generated based on the hash function. The anti-collision property of the hash function ensures the privacy protection of the real identity of the device, thus realizing the anonymous security of the smart meter. The unforgeability of the evidence based on the ECC accumulator ensures that only legitimate smart meter devices have anonymous identity credentials, and it is difficult for attackers to forge valid anonymous identity credentials, thus realizing the secure access of the smart meter. For the revoked smart meter, relying on the ECC accumulator data structure, its anonymous identity credentials will be permanently invalidated and cannot be used again by attackers, thus realizing the secure revocation of the smart meter.

[0028] The performance of this mechanism is analyzed from three aspects: storage, communication and computing overhead. (1) Storage overhead: The device management center only needs to store the latest accumulated value and private key a f =s, there is no need to store the identity IDs of all smart meters, the smart meters only need to store their anonymous identity IDs * and the latest anonymous identity credential W. (2) Communication overhead: When a new device is added or an untrusted device is deleted, the device management center needs to broadcast the corresponding auxiliary information to the smart meter. The auxiliary information is a short value and does not bring a lot of communication overhead. (3) Computational overhead: The computational overhead of the device management center mainly comes from the calculation of the accumulated value, the generation and verification of the anonymous identity credential of the smart meter, and the computational overhead of the smart meter is the update calculation of its own anonymous credential. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a model diagram of a smart meter security access system based on ECC accumulator;

[0030] Figure 2The figure is a flow chart of a smart meter security access method based on ECC accumulator. DETAILED DESCRIPTION

[0031] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.

[0032] This embodiment discloses a smart meter security access system based on ECC accumulator. The system model is as follows: Figure 1 As shown in the figure, it includes the device management center of the control layer and the smart meter of the device layer, which are connected by the communication channel of the network layer. The device management center collects user electricity consumption data and is responsible for the access management of smart meters (including the issuance, authentication and revocation of anonymous identity credentials); the communication channel is the bridge for interaction between the device management center and the smart meter; the smart meter regularly monitors the user's electricity consumption behavior and transmits the collected data to the device management center after anonymous authentication; the smart meter whose anonymous identity credentials are revoked fails the authentication and cannot access the device management center again.

[0033] This embodiment discloses a smart meter security access method based on an ECC accumulator. The method flow is as follows: Figure 2 As shown in the figure, it includes four stages: registration, authentication, revocation and update. Both smart meters and device management centers transmit data through a secure communication channel. The device management center is responsible for the identity registration, access authentication and revocation of smart meters. Smart meters update their anonymous identity credentials locally. Assume that the device management center has been equipped with an advanced intrusion detection system, which can detect malicious devices in time and revoke their trusted identity credentials in time to effectively prevent them from accessing again. The specific scheme is as follows: In the system initialization stage, the device management center generates relevant security parameters and arrays. After receiving the registration application of the smart meter, the hash algorithm is first called to generate the anonymous identity of the device, and then the ECC accumulator member addition algorithm is called to generate an anonymous identity credential for it, and the current accumulated value is updated. In the authentication stage, the smart meter applies for access authentication to the device management center with the anonymous identity and credentials. The device management center calls the ECC accumulator member verification algorithm for calculation verification. If the verification passes, the smart meter can be successfully accessed; otherwise, the authentication fails. For smart meters that fail authentication or behave abnormally, the device management center focuses on observing their behavior. For smart meters that have been attacked or tampered with, the device management center calls the ECC accumulator member deletion algorithm to revoke the anonymous identity credentials of the meter. In summary, the trusted access authentication and secure revocation of smart meters are achieved, while protecting their identity privacy information and achieving anonymity.

[0034] Each step of the method of the present invention is specifically described as follows:

[0035] System initialization: select a safety parameter l (for example, a larger safety constant 128), use the bilinear pairing generator BPG to generate a tuple t = (p, G1, G M ,e,P) and private key Where p is a prime number of length l, G1 is a cyclic additive group of order p, G M is a multiplication group of order p, a bilinear map e:G1×G M →G M , P is the generator of G1, is the set of all numbers less than p and coprime to p, R represents a randomly selected number from the set; calculate the tuple t′=(P,sP,…,s q P), where q is the upper limit of the elements that the accumulator can add. In the tuple t, t', two functions (f, g) are defined: f:Z p ×Z P →Z P , and g:Z p →G1, u∈Z p .

[0036] The domain of the elements to be accumulated is Z P \{-s}, private key is a f =s, the private key is used to generate the certificate. All the elements to be accumulated in the set are accumulated into a short accumulated value, which is used for membership proof. The domain of the accumulated value is G1.

[0037] Select hash function h:{0,1} * →Z P \{-s}.

[0038] Registration stage:

[0039] Assume that the current accumulated value is A, and the accumulated member set is X = {x1,…,x k}, where x is the anonymous identity of the registered smart meter.

[0040] The device management center calculates the anonymous ID of the smart meter based on its unique ID * =h(ID); judge ID * Does it belong to the set X? If so, the identity ID has been registered. Otherwise, the updated cumulative value A′=g(f(u,X∪{ID *}))=(ID * +s)A, add the anonymous identity of the device to the current member set, and generate the anonymous identity credential W=A of the smart meter. Broadcast information inf add =ID* To other smart meters.

[0041] During the registration phase, the device management center does not store the real identity ID of the smart meter.

[0042] Certification stage:

[0043] Smart meters rely on their anonymous ID * and anonymous identity credential W to apply for authentication from the device management center, and the device management center calculates (ID * +s)W is equal to A′. If they are equal, the smart meter passes the verification and can successfully connect to the device management center for data transmission. For devices that fail the verification, it means that their anonymous identity credentials may have been tampered with. If the smart meter is attacked by hackers, the device management center can further revoke its anonymous identity credentials and remove the smart meter from the accumulator.

[0044] Revocation phase:

[0045] For smart meters with abnormal behavior, the device management center can revoke their anonymous identity credentials. Assume that the anonymous identity of the smart meter is ID * , using the ECC accumulator member deletion algorithm to calculate the updated cumulative value V′=g(f(u,X\{ID *}))=1 / (ID * +s)A, which invalidates the anonymous identity certificate of the device and deletes the anonymous identity of the device from the current member set. Broadcast information inf del =ID * To other smart meters.

[0046] Update phase:

[0047] When a new smart meter is registered or an untrusted smart meter is revoked, the accumulated value is updated from A to A′, and other smart meters need to update their anonymous identity credentials accordingly. * , Smart meter with anonymous identity credential W:

[0048] (1) When a new smart meter is registered, the anonymous identity credentials of other smart meters are updated to W′=A+(inf add -ID * )W;

[0049] (2) When an untrusted device is revoked, the anonymous identity credentials of other smart meters are updated to W′=(1 / (inf del -ID * ))(WA′).

[0050] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions of the technical solutions of the present invention made by ordinary technicians in the field should all be included in the protection scope of the present invention. The protection scope of the present invention shall be based on what is defined in the claims.

Claims

1. A smart meter security access method based on an ECC accumulator, based on a system comprising a device management center and a smart meter connected through a communication channel, It is characterized in that The method comprises the following steps: 1) The device management center initializes and generates relevant security parameters and tuples, the steps of which include: selecting a security parameter l, using a bilinear pairing instance generator BPG to generate a tuple t = (p, G 1 ,G M ,e,P) and private key Where p is a prime number of length l, G 1 is a cyclic additive group of order p, G M is a multiplication group of order p, the bilinear map e:G 1 ×G M →G M , P is G 1 The generator of is the set of all numbers less than p and coprime to p, R represents a randomly selected number from the set; calculate the tuple t′=(P,sP,…,s q P), where q is the upper limit of the elements accumulated by the accumulator; two functions (f, g) are defined in the tuple t, t′: f:Z p ×Z p →Z p , f:(u,x)→(x+s)u and g:Z p →G 1 , g: u∈Z p ; Then, after receiving the registration application of the smart meter, the device management center first calls the hash algorithm to generate the anonymous identity of the smart meter, and then calls the ECC accumulator member addition algorithm to generate an anonymous identity credential for the smart meter and update the current accumulated value; 2) During authentication, the smart meter applies for access authentication to the device management center with the anonymous identity identifier and anonymous identity credential. The device management center calls the ECC accumulator member verification algorithm for calculation verification. If the verification passes, the authentication is successful and the smart meter is allowed to access. Otherwise, the authentication fails. 3) For smart meters that fail authentication or behave abnormally, the device management center detects the smart meter. If the smart meter is attacked or tampered with, the device management center calls the ECC accumulator member deletion algorithm to revoke the anonymous identity credentials of the smart meter.

2. The method according to claim 1, It is characterized in that In step 1), the accumulated value is obtained by accumulating the elements to be accumulated, where the domain of the elements to be accumulated is Z p \{-s}, the domain of the accumulated value is G 1 ; The function of the hash algorithm is h:{0,1} * →Z p \{-s}.

3. The method according to claim 2, It is characterized in that In step 1), the device management center calculates the anonymous ID of the smart meter based on its unique ID * =h(ID); judge ID * Whether it belongs to the set X, if it does, the identity ID has been registered; otherwise, call the ECC accumulator member addition algorithm to add the anonymous identity of the smart meter to the current member set X = {x 1 ,…,x k }, where x 1 ,…,x k It is the anonymous identity identifier of the registered smart meter, and generates the anonymous identity credential W=A of the smart meter, where A is the current accumulated value.

4. The method according to claim 3, It is characterized in that The algorithm for adding ECC accumulator members in step 1) is: A′=g(f(u,X∪{ID * }))=(ID * +s)A; where A′ is the updated accumulated value.

5. The method according to claim 4, It is characterized in that In step 1), when a new smart meter is registered, the anonymous identity credentials of other smart meters are updated to W ′ =A+(inf add -ID * )W, where inf add Indicates an additional anonymous identity.

6. The method according to claim 4, It is characterized in that In step 2), the device management center calls the ECC accumulator member verification algorithm to perform calculation verification, which means: calling the ECC accumulator member verification algorithm to calculate (ID * +s)W, and determine whether it is equal to A′.

7. The method according to claim 3, It is characterized in that The ECC accumulator member deletion algorithm in step 3) is: V′=g(f(u,X\{ID * }))=1 / (ID * +s)A, where V′ is the updated accumulated value.

8. The method according to claim 4, It is characterized in that In step 3), when a smart meter is revoked, the anonymous identity credentials of other smart meters are updated to W′=(1 / (inf del -ID * ))(WA′), where inf del Represents a revoked anonymous identity.

9. A smart meter security access system based on ECC accumulator, used to implement the method described in any one of claims 1 to 8, It is characterized in that The system includes a device management center and a smart meter connected through a communication channel, wherein: The device management center is used to aggregate user electricity consumption data and is responsible for the access management of smart meters, including the issuance, authentication and revocation of anonymous identity credentials; Smart meters are used to regularly monitor users' electricity usage behavior and transmit the collected data to the device management center after anonymous authentication. When the anonymous identity credentials are revoked, the authentication fails and access to the device management center cannot be made again.

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