A certificateless key negotiation method for power consumption information collection system

Abstract

This invention discloses a certificate-free key negotiation method for an electricity consumption information collection system. Before key negotiation, the metering center's electricity consumption information collection system management server initializes system parameters such as private keys and public keys for the detection server C and terminal device T, respectively. The steps are as follows: (1) System establishment; (2) Generating a partial private key; (3) Setting a secret value; (4) Setting the key; (5) Setting the public key. The solution of this invention can be used to solve the problems caused by certificate management in key negotiation of smart grid electricity consumption information collection systems, power Internet of Things based on low-power NB-IoT, and new generation smart grid electricity consumption information collection systems based on power satellite IoT, resulting in high computational overhead, communication delay, storage space, and high power consumption of terminals and communication modules.

Description

Technical Field

[0001] The present invention relates to the field of information security and cryptographic technology of electric power Internet of Things, and in particular to a certificateless key negotiation method for an electricity consumption information collection system. Background Art

[0002] With the application and development of smart grids and power Internet of Things, related network information security issues have also been put on the agenda. In the collection of smart grid electricity consumption information, the application of information security and cryptographic technology is an important research and application direction. In the smart grid electricity consumption information collection system, the key negotiation between the main station and the client-side terminal or smart energy meter requires a wireless communication channel, and the computing resources of the terminal equipment are limited and huge in number. With the development of NB-IoT Internet of Things and power satellite Internet of Things and their application in smart grid electricity consumption information collection systems, smart grid electricity consumption information collection systems have a development trend of low power consumption and narrowband communication, and there is an urgent need for corresponding low-overhead, efficient and secure cryptographic technology. The market demand for the present invention has also arisen as the times require.

[0003] The key negotiation scheme currently used in smart grid electricity consumption information collection is based on traditional public key certificates. During key negotiation, the metering management center (CA) needs to issue a certificate to prove that the public key corresponds to the client terminal and has not been tampered with or replaced by a third party.

[0004] In the smart grid electricity consumption information collection system, especially the narrowband and low-power NB-IoT power Internet of Things used in the smart grid electricity consumption information collection system, too complex cryptographic systems are obviously not applicable. There is also the power satellite Internet of Things that has just started to be used in the smart grid electricity consumption information collection system, which also has the characteristics of limited wireless communication bandwidth, a large number of terminals, limited computing resources and low power consumption. At present, the key negotiation of the smart grid electricity consumption information collection system based on certificates requires the metering management center (CA) to issue a public key certificate to the client-side terminal or smart energy meter to ensure the uniqueness and irreplaceability of the public key. The overhead caused by a series of cumbersome operations caused by the metering management center (CA) to manage the certificate will cause problems such as large computing overhead, communication delay, storage space, and high power consumption of terminals and communication modules in the new generation of smart grid electricity consumption information collection systems such as the smart grid electricity consumption information collection system, the power Internet of Things based on low-power NB-IoT, and the power satellite Internet of Things. Summary of the invention

[0005] The object of the present invention is to provide a certificateless key negotiation method for an electricity consumption information collection system.

[0006] To achieve the above object, the present invention provides a certificateless key negotiation method for an electricity consumption information collection system. Before key negotiation, the management server of the electricity consumption information collection system of the metering center initializes the private key, public key and other system parameters for the detection server C and the terminal device T respectively. The steps are as follows:

[0007] (1) System establishment: A trusted third-party key generation center (KGC) performs the following operations to generate the master key and system parameters:

[0008] Generate system parameters (G1, G2, q, e), where G1 and G2 are additive and multiplicative cyclic groups of the same prime order q, e: G1×G1→G2 is a bilinear pairing, and select generator P∈ R G1; Select As the system master key, and calculate P pub =sP; KGC precomputes e(P,P) = g∈G2, e(P,-P pub ); Select 4 Hash functions: H1: H2: H3: H4: The system public parameters are params = {e, G1, G2, q, P, P pub ,g, H1,H2,H3,H4}, KGC keeps the master key s;

[0009] (2) Generate a partial private key. KGC uses the parameters params, s and the user's identity ID ID , calculate Q ID =H1(ID ID ),get D is the user's partial key, which is transmitted through a secure channel ID Sent to the user, the user passes the equation e(DID,P pub +Q A P) = verification of g, judging whether the private key is legal;

[0010] (3) Set the secret value, and the user selects as its secret value;

[0011] (4) Set the key, user private key sk ID =xD ID Based on system parameters, D ID And the secret value x is generated;

[0012] (5) Set the public key and use the system parameters and the user's secret value x to obtain the user's public key PK ID =<pk1,pk2>, where pk1=xP,

[0013] In a preferred embodiment, the method is performed by a terminal T, and the method comprises the following steps:

[0014] Send a key negotiation request message to the measurement center detection server;

[0015] Receiving a key negotiation response message sent by a measurement center detection server;

[0016] After receiving the key negotiation response message, sending a key negotiation confirmation message to the measurement center detection server;

[0017] The key negotiation request message is generated through the following steps:

[0018] Pick a random number And use the public key of terminal T to calculate U1=r1pk T1 , where pk T1 is the public key of the terminal T;

[0019] Get the current timestamp t1 of the terminal T, perform hash processing on the message m1 and the current timestamp t1, and obtain the message hash value Where m1 = Type||Subtype||TESAM, where TESAM is the terminal's security chip serial number;

[0020] Use the system public parameters, the identity ID of terminal T, and the private key sk of terminal T T , perform the following operations: Calculate R1, h1, and S1, where h1=H2(L1,TESAM,PK T ,R1), S1=(r1+h1)sk T , the signature of message m1 is Sign1=(U1,S1,R1), where sk T is the private key of device T, where sk T =x1D T ;

[0021] A key negotiation request message M1 is sent to the measurement center detection server, where M1=m1||t1||Sign1.

[0022] In a preferred embodiment, the key negotiation response message is generated by the measurement center detection server C, wherein the key negotiation response message is generated by the following steps:

[0023] After receiving the key negotiation request message M1, the measurement center detection server C first parses the message, obtains the timestamp t1 and verifies the freshness of the request message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected;

[0024] Input system public parameters and terminal T's public key PK T , message hash value L1, signature of message m1, perform the following operations: calculate h1 = H2 (L1, TESAM, PK1, R1), if and only if the equation

[0025]

[0026] Established, signature accepted;

[0027] Pick a random number Use the public key of the measurement center to calculate U2=r2pk C1 ;

[0028] Get the current timestamp t2 of the measurement center detection server, perform hash processing on messages m2 and t2, and obtain the second message hash value Where, m2 = Type||Subtype||MAC;

[0029] Using the system public parameters, the measurement center detects the private key sk of server C C =x2D C , do the following: Calculate h2=H2(L2,MAC,PK C ,R2)、S2=(r2+h2)sk C , the signature of message m2 is Sign2 = (U2, S2, R2).

[0030] Further calculation of K 12 =U1x2r2, and obtain the temporary session key DK=K 12 =x1x2r1r2P.

[0031] The key negotiation response message M2 is sent to the terminal T via a wireless channel, where M2=m2||t2||Sign2.

[0032] In a preferred embodiment, after receiving the key negotiation response message, the terminal T sends the key negotiation confirmation message to the measurement center detection server C through the following steps:

[0033] After receiving the key negotiation response message M2, the terminal T first parses the message, obtains the timestamp t2 and verifies the freshness of the request message. If the verification is successful, the next step is performed, otherwise the message is rejected;

[0034] Input system public parameters and the public key PK of the measurement center detection server C C , the second message hash value L2, Sign2 = (U2, S2, R2), perform the following operations: calculate h2 = H2 (L2, MAC, PK2, R2), if and only if the equation

[0035]

[0036] Established, signatures accepted.

[0037] Further calculation of K 21 =U2x1r1, and obtain the temporary session key DK=K 21 =x1x2r1r2P;

[0038] Get the current timestamp t3 of terminal T, and the message m3, t3 and temporary session key K 21 Perform hash processing to obtain the third message hash value Calculate the signature Sign3=L3P, where m3=Type||Subtype||TESAM;

[0039] A key negotiation confirmation message M3 is sent through a wireless channel to the measurement center detection server C, where M3 = m3||t3||Sign3.

[0040] In a preferred embodiment, the method is performed by a measurement center detection server C, and the method comprises the following steps:

[0041] Receiving a key negotiation request message sent by terminal T;

[0042] Send a key negotiation response message to terminal T;

[0043] Receiving a key negotiation confirmation message sent by terminal T;

[0044] Verify the key negotiation confirmation message. If the verification is successful, the key negotiation is completed. If the verification is unsuccessful, a warning message of negotiation failure is given and the terminal T is notified to re-initiate the key negotiation.

[0045] The verification of the key negotiation confirmation message by the measurement center detection service C is completed through the following steps:

[0046] After receiving M3, the measurement center detection service C obtains the timestamp t3 to verify the freshness of the confirmation message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected;

[0047] The message m3, t3 after the confirmation message is parsed and the temporary session key K generated by the measurement center detection service C 12 Perform hash processing to obtain the message hash value And calculate the signature Sign'3 = L'3P;

[0048] Compare Sign'3 and Sign3 to see if they are equal. If they are equal, both parties have verified each other's identity and hold the temporary session key DK. If they are not the same, the measurement center detection service C will give a warning message of negotiation failure and notify terminal T to re-initiate key negotiation.

[0049] Compared with the prior art, the present invention has the following advantages: according to the detection key server interface description of the object-oriented smart grid electricity consumption information collection system issued by the State Grid Metering Center, the terminal-oriented key negotiation adopts a digital signature connection authentication mechanism. According to the above requirements, the present invention designs a terminal-oriented certificateless key negotiation scheme based on a provably secure and efficient certificateless digital signature scheme using only one bilinear pairing, based on the computational Diffie-Hellman (CDH) problem. The security proof and efficiency analysis of this certificateless digital signature scheme have been described in detail in another patent application. The certificateless key negotiation scheme of the present invention can be used to solve the problems of high computational overhead, communication delay, storage space, and high power consumption of terminals and communication modules caused by the management of certificates in the key negotiation of the smart grid electricity consumption information collection system, the power Internet of Things based on the low-power NB-IoT, and the power satellite Internet of Things. Because the certificateless key negotiation eliminates the necessity of traditional public key certificates in key negotiation, there is no overhead caused by a series of cumbersome operations caused by the metering management center to manage certificates during key negotiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a flowchart of a key negotiation process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0052] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0053] The certificateless key negotiation method of the electricity consumption information collection system comprises the following steps:

[0054] Before key negotiation, the management server of the power consumption information collection system of the metering center initializes the private key, public key and other system parameters for the detection server C and the terminal device T respectively. The steps are as follows:

[0055] (1) System establishment: A trusted third-party key generation center (KGC) performs the following operations to generate the master key and system parameters:

[0056] Generate system parameters (G1, G2, q, e), where G1 and G2 are additive and multiplicative cyclic groups of the same prime order q, e: G1×G1→G2 is a bilinear pairing, and select generator P∈ R G1; Select As the system master key, and calculate P pub =sP; KGC precomputes e(P,P) = g∈G2, e(P,-P pub ); Select 4 Hash functions: H1: H2: H3: H4: The system public parameters are params = {e, G1, G2, q, P, P pub ,g, H1,H2,H3,H4}, KGC keeps the master key s;

[0057] (2) Generate a partial private key. KGC uses the parameters params, s and the user's identity ID ID , calculate Q ID =H1(ID ID ),get D is the user's partial key, which is transmitted through a secure channel ID Sent to the user, the user passes the equation e(D ID ,P pub +Q A P) = verification of g, judging whether the private key is legal;

[0058] (3) Set the secret value, and the user selects as its secret value;

[0059] (4) Set the key, user private key sk ID =xD ID Based on system parameters, D ID And the secret value x is generated;

[0060] (5) Set the public key and use the system parameters and the user's secret value x to obtain the user's public key PK ID =<pk1,pk2>, where pk1=xP,

[0061] (6) Key negotiation.

[0062] Assume that terminal T has a private key sk T , the public key is PK T = < pk T1 ,pk T2 >; The identity ID is represented by the terminal security chip serial number TESAM; the measurement center detects that the server C has a private key sk C , the public key is PK C = < pk C1 ,pk C2 >, the identity ID is represented by the server's MAC address. As shown in the figure, the entire key negotiation process is divided into three steps: key negotiation request phase, key negotiation response phase and key negotiation confirmation phase. The specific negotiation process is described as follows.

[0063] Figure 1 is a flowchart of a key negotiation process according to an embodiment of the present invention.

[0064] 1) Terminal T generates an application connection establishment message, which is a key negotiation request message, and sends this message to the measurement center detection server C. Table 1 shows the data structure of this message.

[0065] The specific generation steps are as follows:

[0066] Table 1 Key negotiation request message

[0067] name illustrate Type Message Type Subtype Message subtype ID Terminal security chip serial number TESAM <![CDATA[t1]]> Timestamp <![CDATA[Sign1]]> sign

[0068] ①Terminal T selects a random number And use the public key of terminal T to calculate U1=r1pk T1 ;

[0069] ② Get the current timestamp t1 of terminal T, perform hash processing on message m1 and current timestamp t1 (where m1 = Type||Subtype||TESAM), and get the message hash value

[0070] ③ Use the system public parameters, the terminal T's identity ID (TESAM), and the device T's private key sk T =x1D T , perform the following operations: Calculate h1=H2(L1,TESAM,PK T ,R1),S1=(r1+h1)sk T , the signature of message m1 is Sign1 = (U1, S1, R1).

[0071] ④Terminal T sends M1=m1||t1||Sign1 message to the measurement center detection server C through the wireless channel.

[0072] 2) After receiving M1, the measurement center detection server C first performs message parsing and signature verification, and then generates a key negotiation response message with a message structure as shown in Table 2.

[0073] Table 2 Key negotiation response message

[0074] name illustrate Type Message Type Subtype Message subtype ID MAC address of the server <![CDATA[t2]]> Timestamp <![CDATA[Sign2]]> sign

[0075] The specific steps of generating a key negotiation request message and a response message for the measurement center detection server are as follows.

[0076] ① After the measurement center detection server C receives M1=m1||t1||Sign1, it first parses the message, obtains the timestamp t1 and verifies the freshness of the request message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected;

[0077] ② Input system public parameters and terminal T’s public key PK T , information m1∈{0,l} * With the hash value L1 of timestamp t1, Sign1 = (U1, S1, R1), perform the following operation: Calculate h1 = H2 (L1, TESAM, PK1, R1), if and only if the equation

[0078]

[0079] Established, signatures accepted.

[0080] Correctness:

[0081]

[0082] ③The measurement center detects that server C selects a random number Use the public key of the measurement center to calculate U2=r2pk C1 ;

[0083] ④ Get the server's current timestamp t2, hash messages m2 and t2 (where m2 = Type||Subtype||MAC), M2 = m2||t2||Sign2, and get the message hash value

[0084] ⑤ Using the system public parameters, the measurement center detects the private key sk of server C C =x2D C , perform the following operations: Calculate h2=H2(L2,MAC,PKC ,R2),S2=(r2+h2)sk C , the signature of message m2 is Sign2 = (U2, S2, R2).

[0085] ⑥ The measurement center detection server C further calculates K 12 =U1x2r2, and obtain the temporary session key DK=K 12 =x1x2r1r2P.

[0086] ⑦ The measurement center detection server C sends the M2=m2||t2||Sign2 message to the terminal T through the wireless channel.

[0087] 3) After receiving M2, terminal T first performs message parsing and signature verification, and then generates a key negotiation response message with a message structure as shown in Table 3.

[0088] Table 3 Key negotiation confirmation message

[0089] name illustrate Type Message Type Subtype Message subtype ID Terminal security chip serial number TESAM <![CDATA[t3]]> Timestamp <![CDATA[Sign3]]> sign

[0090] The specific steps of key negotiation response message processing and confirmation message generation are as follows.

[0091] ① After receiving M2=m2||t2||Sign2, terminal T first parses the message, obtains the timestamp t2 and verifies the freshness of the request message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected;

[0092] ② Input system public parameters and the public key PK of the measurement center detection server C C , information m2∈{0,l} * With the hash value L2 of timestamp t2, Sign2 = (U2, S2, R2), perform the following operation: Calculate h2 = H2 (L2, MAC, PK2, R2), if and only if the equation

[0093]

[0094] Established, signatures accepted.

[0095] ③Terminal T further calculates K 21 =U2x1r1, and obtain the temporary session key DK=K 21 =x1x2r1r2P.

[0096] ④ Get the current timestamp t3 of terminal T, and the message m3, t3 and temporary session key K 21 Perform hash processing (where m3 = Type||Subtype||TESAM) to obtain the message hash value Calculate the signature Sign3 = L3P;

[0097] ⑤Terminal T sends M3=m3||t3||Sign3 message to the measurement center detection server C through the wireless channel.

[0098] 4) After receiving M3, the measurement center detection server C obtains the timestamp t3 to verify the freshness of the confirmation message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected; the message m3 and t3 after the confirmation message is parsed, and the temporary session key K generated by the measurement center detection service C 12 Perform hash processing to obtain the message hash value Calculate the signature Sign'3 = L'3P; compare whether Sign'3 is equal to Sign3. If they are equal, then both parties have verified each other's identity and hold the temporary session key DK. If they are not the same, the measurement center detection service C will give a warning message of negotiation failure and notify terminal T to re-initiate key negotiation.

[0099] The scheme of the present invention was subjected to a safety analysis, and the results were as follows:

[0100] (1) Anti-replay attack

[0101] A replay attack is when an active attacker intercepts a message request and then uses it to impersonate a legitimate user. In the protocol, timestamps t1, t2, and t3 are used in key negotiation request, response, and confirmation messages to prevent replay attacks. In order to pass authentication, the attacker must modify t1, t2, and t3 to new timestamps that are consistent with the recipient's local clock. Once t1, t2, and t3 have been modified, Sign1, Sign2, and Sign3 must be modified. However, since the attacker does not know the user's private key sk T ,sk C And the selected random numbers r1, r2 and the temporary negotiated session key K 21 , so the attacker cannot obtain valid Sign1, Sign2 and Sign3. Therefore, the protocol can resist replay attacks.

[0102] (2) Message tamper-proofing

[0103] A tampering attack is when an active attacker intercepts a message request and tampers with the request message to obtain a legitimate request message. In the key negotiation protocol, signatures Sign1, Sign2, and Sign3 are used in the key negotiation request, response, and confirmation messages to prevent message tampering attacks. By intercepting the message, the attacker knows the messages m1, m2, m3 corresponding to the message and the hash values ​​L1, L2, L3 corresponding to the message. In order to successfully tamper with the messages M1, M2, and M3, the attacker must recalculate the signatures Sign1, Sign2, and Sign3 of the tampered message m′. However, since the attacker does not know the user's private key sk T ,sk C As well as the selected random numbers r1 and r2, S' and R' cannot be successfully calculated, and signatures Sign1, Sign2 and Sign3 cannot be obtained, resulting in signature verification failure. Therefore, the protocol can resist message tampering attacks.

[0104] In summary, the present invention discloses a certificateless key negotiation method for an electricity consumption information collection system. Before key negotiation, the management server of the electricity consumption information collection system of the metering center respectively initializes the private key, public key and other system parameters for the detection server C and the terminal device T, and the steps are as follows: (1) system establishment; (2) generating part of the private key; (3) setting the secret value; (4) setting the key; (5) setting the public key. The scheme of the present invention can be used to solve the problems of high computing overhead, communication delay, storage space and high power consumption of the terminal and communication module caused by the management of certificates when performing key negotiation in the smart grid electricity consumption information collection system, the power Internet of Things based on low-power NB-IoT and the power satellite Internet of Things.

[0105] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A certificateless key negotiation method for an electricity consumption information collection system, characterized in that: Before key negotiation, the management server of the power consumption information collection system of the metering center initializes the private key, public key and system parameters for the detection server C and the terminal device T respectively. The steps are as follows: (1) System establishment: A trusted third-party key generation center (KGC) performs the following operations to generate the master key and system parameters: Generate system parameters (G1, G2, q, e), where G1 and G2 are additive and multiplicative cyclic groups of the same prime order q, e: G1×G1→G2 is a bilinear pairing, and select generator P∈ R G1; Select As the system master key, and calculate P pub =sP; KGC precomputes e(P,P) = g∈G2, e(P,-P pub ); Select 4 Hash functions: The system public parameters are params = {e, G1, G2, q, P, P pub ,g,H1,H2,H3,H4}, KGC keeps the master key s; (2) Generate a partial private key. KGC uses the parameters params, s and the user's identity ID ID , calculate Q ID =H1(ID ID ),get D is the user's partial key, which is transmitted through a secure channel ID Sent to the user, the user passes the equation e(D ID ,P pub +Q ID P) = verification of g, judging whether the private key is legal; (3) Set the secret value, and the user selects as its secret value; (4) Set the key, user private key sk ID =xD ID Based on system parameters, D ID And the secret value x is generated; (5) Set the public key and use the system parameters and the user's secret value x to obtain the user's public key PK ID =<pk1,pk2>, where pk1=xP, The method is performed by a terminal T, and comprises the following steps: Send a key negotiation request message to the measurement center detection server; Receiving a key negotiation response message sent by a measurement center detection server; After receiving the key negotiation response message, sending a key negotiation confirmation message to the measurement center detection server; The key negotiation request message is generated through the following steps: Pick a random number And use the public key of terminal T to calculate U1=r1pk T1 , where pk T1 is the public key of the terminal T; Get the current timestamp t1 of the terminal T, perform hash processing on the message m1 and the current timestamp t1, and obtain the message hash value Where m1 = Type||Subtype||TESAM, where TESAM is the terminal's security chip serial number, Type indicates the message type, and Subtype indicates the message subtype; Use the system public parameters, the identity ID of terminal T, and the private key sk of terminal T T , perform the following operations: Calculate R1, h1, and S1, where h1=H2(L1,TESAM,PK T ,R1),S1=(r1+h1)sk T , the signature of message m1 is Sign1=(U1,S1,R1), where sk T is the private key of device T, where sk T =x1D T ; A key negotiation request message M1 is sent to the measurement center detection server, where M1=m1||t1||Sign1.

2. A certificateless key negotiation method for an electricity consumption information collection system as claimed in claim 1, wherein: The key negotiation response message is generated by the measurement center detection server C, wherein the key negotiation response message is generated by the following steps: After receiving the key negotiation request message M1, the measurement center detection server C first parses the message, obtains the timestamp t1 and verifies the freshness of the request message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected; Input system public parameters and terminal T's public key PK T , message hash value L1, signature of message m1, perform the following operations: calculate h1 = H2 (L1, TESAM, PK1, R1), if and only if the equation Established, signature accepted; Pick a random number Use the public key of the measurement center to calculate U2=r2pk C1 ; Get the current timestamp t2 of the measurement center detection server, perform hash processing on messages m2 and t2, and obtain the second message hash value Where m2 = Type||Subtype||MAC; Using the system public parameters, the measurement center detects the private key sk of server C C =x2D C , do the following: Calculate h2=H2(L2,MAC,PK C ,R2)、S2=(r2+h2)sk C , the signature of message m2 is Sign2 = (U2, S2, R2); Further calculation of K 12 =U1x2r2, and obtain the temporary session key DK=K 12 =x1x2r1r2P; The key negotiation response message M2 is sent to the terminal T via a wireless channel, where M2=m2||t2||Sign2.

3. A certificateless key negotiation method for an electricity consumption information collection system as claimed in claim 2, wherein: After receiving the key negotiation response message, the terminal T sends a key negotiation confirmation message to the measurement center detection server C, which is generated by the following steps: After receiving the key negotiation response message M2, the terminal T first parses the message, obtains the timestamp t2 and verifies the freshness of the request message. If the verification is successful, the next step is performed, otherwise the message is rejected; Input system public parameters and the public key PK of the measurement center detection server C C , the second message hash value L2, Sign2 = (U2, S2, R2), perform the following operations: calculate h2 = H2 (L2, MAC, PK2, R2), if and only if the equation Established, signature accepted; Further calculation of K 21 =U2x1r1, and obtain the temporary session key DK=K 21 =x1x2r1r2P; Get the current timestamp t3 of terminal T, and the message m3, t3 and temporary session key K 21 Perform hash processing to obtain the third message hash value Calculate the signature Sign3=L3P, where m3=Type||Subtype||TESAM; A key negotiation confirmation message M3 is sent via a wireless channel to the measurement center detection server C, where M3=m3||t3||Sign3.

4. A certificateless key negotiation method for an electricity consumption information collection system as claimed in claim 3, wherein: The method is executed by a measurement center detection server C, and the method comprises the following steps: Receiving a key negotiation request message sent by terminal T; Send a key negotiation response message to terminal T; Receiving a key negotiation confirmation message sent by terminal T; Verify the key negotiation confirmation message. If the verification is successful, the key negotiation is completed. If the verification is unsuccessful, a warning message of negotiation failure is given and the terminal T is notified to re-initiate the key negotiation. The verification of the key negotiation confirmation message by the measurement center detection service C is completed through the following steps: After receiving M3, the measurement center detection service C obtains the timestamp t3 to verify the freshness of the confirmation message. If the verification is successful, it proceeds to the next step, otherwise the message is rejected; The message m3, t3 after the confirmation message is parsed and the temporary session key K generated by the measurement center detection service C 12 Perform hash processing to obtain the message hash value And calculate the signature Sign′3=L′3P; Compare Sign'3 and Sign3 to see if they are equal. If they are equal, both parties have verified each other's identity and hold the temporary session key DK. If they are not the same, the measurement center detection service C will give a warning message of negotiation failure and notify terminal T to re-initiate key negotiation.

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