Two-way authentication key negotiation method and electricity consumption information collection system using the method

Abstract

This invention belongs to the field of smart grid technology, specifically relating to a two-way authentication key negotiation method and an electricity consumption information collection system using this method. During the two-way authentication key negotiation process, both parties generate their own digital signatures, and include the digital signatures and timestamps in the generated authentication key negotiation request message, authentication key negotiation response message, or authentication key negotiation confirmation message. After each signature is successfully authenticated, both parties are considered to have authenticated each other's identities. This method applies a certificate-free authentication key negotiation protocol based on the elliptic curve discrete logarithm problem (without bilinear pairings) to a high-speed dual-mode communication system for electricity consumption information collection. This eliminates the necessity of traditional public key certificates in authentication key negotiation, avoiding the problems of high computational overhead, communication latency, storage space, and high power consumption caused by certificate management in the high-speed dual-mode communication system for electricity consumption information collection. Furthermore, the addition of timestamps to the messages helps resist replay attacks.

Description

Technical Field

[0001] This invention belongs to the field of smart grid technology, specifically relating to a two-way authentication key negotiation method and an electricity consumption information collection system using this method. Background Technology

[0002] With the application of high-speed power line carrier low-power wireless dual-mode communication technology in smart grid electricity information collection systems, requirements for information security protection have also been raised. Dual-mode communication chips possess a unique and unchangeable chip ID number. Dual-mode communication units should be able to complete secure interaction with the master station based on the chip ID number and a lightweight private cryptographic algorithm, realizing information security protection functions such as two-way authentication between the dual-mode communication unit and the master station, communication unit program version management, and end-to-end channel security protection. Furthermore, dual-mode communication units should support two-way authentication and key negotiation. This creates a corresponding market demand for lightweight, low-overhead, efficient, and secure two-way authentication and key negotiation cryptographic technologies.

[0003] Currently, the electricity consumption information collection in smart grids uses a two-way authentication key negotiation scheme based on traditional public key certificates. When conducting two-way authentication key negotiation, the metering management center (CA) needs to issue a certificate to prove that the public key corresponds to a certain communication unit and that the public key has not been tampered with or replaced by a third party.

[0004] The dual-mode communication system of the smart grid electricity consumption information collection system requires a lightweight cryptographic system. Currently, the two-way authentication and key negotiation of the certificate-based smart grid electricity consumption information collection system require the Certificate Authority (CA) to issue public key certificates to the communication units to ensure the uniqueness and non-replaceability of the public keys. The overhead of the CA's cumbersome certificate management operations leads to problems such as high computational overhead, communication latency, storage space requirements, and high power consumption of the communication units in the high-speed dual-mode communication system of the smart grid electricity consumption information collection system. Certificate-free algorithms based on bilinear pairing are inefficient and complex. In finite fields, compared to scalar multiplication and exponential operations, bilinear pairing operations are more time-consuming; the time required for a single bilinear pairing operation is at least 21 times that of a scalar multiplication operation on an elliptic curve. The traditional discrete logarithm problem is far less difficult than the elliptic curve discrete logarithm problem, and its unit bit strength is much lower than that of the elliptic curve discrete logarithm system. Furthermore, a certificate-free signature scheme does not require bilinear pairing operations, thus having lower computational complexity and higher efficiency. Elliptic curve discrete logarithm problems are far more difficult than discrete logarithm problems. However, using shorter keys, elliptic curves can achieve the same level of security as traditional discrete logarithm systems. This results in smaller computational parameters, shorter keys, faster computation speeds, and shorter signatures. However, further improving the security of the scheme remains a challenge, such as enhancing its resistance to replay attacks. Summary of the Invention

[0005] The purpose of this invention is to provide a two-way authentication key negotiation method and an electricity information collection system using this method, so as to solve the problem of how to further improve the anti-replay attack performance in the two-way authentication key negotiation scheme.

[0006] To address the aforementioned technical problems, this invention provides a two-way authentication key negotiation method, comprising the following steps:

[0007] 1) One party obtains its current timestamp t1; combines the system's public parameters, the party's ID, and the party's private key to generate a digital signature Sign1 for message m1; then, based on the digital signature Sign1 and the timestamp t1, it generates an authentication key negotiation request message and sends it to the other party;

[0008] 2) The other party obtains its current timestamp t2; parses the received request message, and verifies the digital signature Sign1. After successful verification, it combines the system's public parameters and the other party's private key to generate the other party's digital signature Sign2 for message m2; and obtains the temporary session key K. 12 Then, based on the digital signature Sign2 and timestamp t2, an authentication key negotiation response message is generated and sent to one party;

[0009] 3) One party parses the received response message and verifies the digital signature Sign2. Upon successful verification, it obtains the temporary session key K. 21 ; Obtain its current timestamp t3, based on the temporary session key K 21 Calculate the digital signature Sign3 of message m3 for one party; then generate an authentication key negotiation confirmation message based on the digital signature Sign3 and the timestamp t3 and send it to the other party.

[0010] 4) The other party parses the received acknowledgment message and, based on the temporary session key K... 12 Verify the digital signature Sign3. If the verification is successful, it is considered that both parties have authenticated each other's identities.

[0011] Its beneficial effects are as follows: This method uses timestamps t1, t2, and t3 in the authentication key negotiation request message, authentication key negotiation response message, and authentication key negotiation confirmation message. In order to pass authentication, the attacker must modify the timestamps t1, t2, and t3 to a new timestamp consistent with the receiver's local clock. Once the timestamps t1, t2, and t3 have been modified, the digital signatures Sign1, Sign2, and Sign3 must also be modified. However, since the attacker does not know the user's private key s... T s C And the selected random numbers r1, r2 and the temporary negotiation session key K 21 Therefore, attackers cannot obtain valid Sign1, Sign2, and Sign3. Thus, the entire protocol is resistant to replay attacks.

[0012] Furthermore, the digital signature Sign1 generated in step 1) is: Sign1 = (R T U T ,U1,R1,s1); where, (R T U T ) is the public key of one party; U1 = [r1]R T r1 is a random number and r1∈[1,n-1], where n is the order; R1=[l1]R T l1 is a random number and l1∈[1,n-1]; H represents the chosen cryptographic hash algorithm, L1 represents the result of hashing message m1 and timestamp t1, and s T For one party's private key, and These are elliptic curves E p Given the x and y coordinates of a point R1 on (a, b), and the elliptic curve y 2 =x 3 +ax+b(mod p), where a, b, x, and y are all in the finite field GF. p In, and satisfying 4a3 +27b 2 (modp)≠0;[]R T R represents T The dot multiplication operation.

[0013] Its advantages are as follows: This method avoids bilinear pairing operations, applying elliptic curve discrete logarithms to bidirectional authentication key negotiation, resulting in lower computational complexity and higher computational efficiency, higher unit bit strength, and the ability to achieve the same security level as traditional discrete logarithm systems when using shorter keys. This leads to smaller computational parameters, shorter keys, faster computation speed, and shorter signatures. Furthermore, using the digital signature Sign1 in the authentication key negotiation request message can prevent message tampering attacks.

[0014] Furthermore, if If the condition is met, the digital signature Sign1 is considered successfully verified; where the key generation center lies on the elliptic curve E. p Select the generator point G in (a,b); and These are points R on the elliptic curve. T The x and y coordinates; P is the primary public key, and P = [d]G, where d is a random number and d∈[1,n-1]; m is the message; []R1 represents the doubling operation of R1, and []G represents the doubling operation of G.

[0015] Furthermore, the digital signature Sign2 generated in step 2) is: Sign2 = (R C U C ,U2,R2,s2); where, (R C U C ) is the other party's public key; U2 = [r2]R C r2 is a random number and r2∈[1,n-1]; R2=[l2]R C l2 is a random number and l2∈[1,n-1]; L2 is the result of hashing message m2 and timestamp t2, s C For the other party's private key, and These are the x and y coordinates of a point R2 on the elliptic curve, respectively; []R C R represents C The dot multiplication operation.

[0016] Its advantages are as follows: This method avoids bilinear pairing operations, applying elliptic curve discrete logarithms to bidirectional authentication key negotiation, resulting in lower computational complexity and higher computational efficiency, higher bit strength, and the ability to achieve the same security level as traditional discrete logarithm systems when using shorter keys. This leads to smaller computational parameters, shorter keys, faster computation speed, and shorter signatures. Furthermore, using the Sign2 digital signature in the authentication key negotiation response message can prevent message tampering attacks.

[0017] Furthermore, the temporary session key K 12 For: K 12 =[v T v C r1r2]Q, Temporary session key K 21 For: K 21 =[v T v C r1r2]Q; where v T For one party's private key; v C The private key of the other party; Q = [k]G, where k is a random number and k∈[1,n-1]; []Q represents the dot multiplication operation of Q.

[0018] Furthermore, if The signature is valid, and the digital signature Sign2 is verified successfully; where []U C U C The doubling operation of R2 is represented by []R2; and These are points R on the elliptic curve. C The x and y coordinates.

[0019] Further, the digital signature Sign3 generated in step 3) is: Sign3 = [L3]G; where L3 is the signature of message m3, timestamp t3 and temporary session key K. 21 The result of hash processing.

[0020] Its advantages are as follows: This method avoids bilinear pairing operations, applying elliptic curve discrete logarithms to bidirectional authentication key negotiation, resulting in lower computational complexity and higher computational efficiency, higher bit strength, and the ability to achieve the same security level as traditional discrete logarithm systems when using shorter keys. This leads to smaller computational parameters, shorter keys, faster computation speed, and shorter signatures. Furthermore, using the Sign3 digital signature in the authentication key negotiation response message can prevent message tampering attacks.

[0021] Furthermore, if the digital signature Sign'3 is equal to the digital signature Sign3, then the digital signature Sign3 is deemed to have been successfully verified; where Sign'3 = [L'3]G, and L'3 represents the verification of message m3, timestamp t3, and temporary session key K. 12 The result of hash processing.

[0022] Furthermore, the content of the authentication key negotiation request message, authentication key negotiation response message, and authentication key negotiation confirmation message all include message type, message subtype, one party's ID, timestamp, and digital signature.

[0023] To address the aforementioned technical problems, the present invention also provides an electricity information collection system, comprising a communication unit and a master station. The communication unit is one party to the two-way authentication key negotiation, and the master station is the other party to the two-way authentication key negotiation. The communication unit and the master station are used to perform two-way authentication key negotiation using the two-way authentication key negotiation method described above.

[0024] Its beneficial effects are as follows: Applying the bidirectional authentication key negotiation method described above to the smart grid electricity consumption information collection system can eliminate the necessity of traditional public key certificates in authentication key negotiation. It also eliminates the overhead caused by the cumbersome operations of certificate management by the metering management center, and avoids the problems of high computational overhead, communication latency, storage space, and high power consumption that arise in the high-speed dual-mode communication system of the smart grid electricity consumption information collection system due to certificate management. Furthermore, it is more efficient and simpler than the bilinear pairing algorithm and superior to traditional discrete logarithmic systems. Moreover, it offers higher security, including resistance to replay attacks and message tampering prevention. Attached Figure Description

[0025] Figure 1 This is a diagram of the authentication key negotiation process of the present invention. Detailed Implementation

[0026] The following is an explanation of some terms.

[0027] Elliptic Curve Discrete Logarithm Problem (ECDLP): Given an elliptic curve E(Fq), points P∈E(Fq) of order n, and Q∈... The elliptic curve discrete logarithm problem refers to determining integers l∈[1,n-1] such that Q=[l]P holds true.

[0028] The Elliptic Curve Discrete Logarithm Problem (ECDLP) assumes that there is no probabilistic polynomial algorithm A that can solve the ECDLP in polynomial time with a non-negligible advantage.

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] Method Implementation Examples:

[0031] This method is applied to a power consumption system data acquisition system, including a dual-mode communication unit T and a master station C. The solution of this invention is implemented on an elliptic curve based on the SM2 national cryptographic algorithm standard, and its security relies on the elliptic curve discrete logarithm problem. A note explanation: || indicates concatenation; for a point G on an elliptic curve, x... G and y G These correspond to the x and y coordinates of point G, respectively; H represents the chosen cryptographic hash algorithm; [a]G represents the doubling operation of G.

[0032] 1. System establishment.

[0033] Key generation center KGC selects a large prime number p and an elliptic curve E. p (a,b):y 2 =x 3 +ax+b(mod p), where a, b, x, and y are all in the finite field GF. p In, and satisfying: 4a 3 +27b 2 (modp)≠0. in E p Select a generator point G from (a,b), and define... <g>Let G be an additive cyclic group, and n be a prime number of order that satisfies security requirements. The SM3 cryptographic hash algorithm used in this method is defined as follows:

[0034] 2. KGC key generation.

[0035] The key generation center KGC randomly selects d∈[1,n-1] as the master key and calculates the master public key as P=[d]G. Let params={E p (a,b),G, <g>,n,P,H} are the common parameters of KGC.

[0036] 3. User key generation.

[0037] 1) Users send their IDs to KGC.

[0038] 2) After receiving the user's ID, KGC randomly selects a k∈[1,n-1], calculates Q=[k]G, and sends Q to the user.

[0039] 3) The user randomly selects v∈[1,n-1] as the private key, calculates R=[v]Q and publishes R as the user's public key.

[0040] 4) KGC generates parameter z, satisfying the condition [H(ID·R)]G=[H(x R ||y R )]P+[z]Q, where x R The x-coordinates and y-coordinates of a point R on the elliptic curve are... R Let be the y-coordinate of point R. Therefore, KGC solves the linear equation. Send the calculated z value to the user.

[0041] 5) The user extracts parameter pairs (R,U) that satisfy the condition [H(ID·r)]G=[H(x r ||y r )]P+[s]R, for this purpose, the user calculates s=v -1 z and U = [s]R. s is the user's private key, and (R,U) is the user's public key.

[0042] 4. Message Signing: Input public parameters params, message m and user private key s, output the signature σ of message m.

[0043] 1) Randomly select l∈[1,n-1], R1=[l]R.

[0044] 2) From Solution

[0045] 3) σ=(R,U,R1,s1) is the complete certificateless digital signature for message m.

[0046] 5. Signature Verification: Input public parameters params, user's identity ID, and message m, and output either reject or accept the signature.

[0047] The correctness of the certificateless digital signature σ on message m based on identity ID and public key (R,U) is verified by the following equation:

[0048]

[0049] If the equation is true, then accept the signature σ; otherwise, reject the signature σ.

[0050] 6. Two-way authentication key negotiation.

[0051] Assume that the dual-mode communication unit T has a private key v T s T The public key is (R T U T The identity ID is represented by a unique, unchangeable chip ID number of the dual-mode communication chip; the master station C possesses the private key v. C s C The public key is (R C U C The identity ID is represented by the MAC address of the main server. As shown in the diagram, the entire two-way authentication key negotiation process consists of three steps: the authentication key negotiation request phase, the authentication key negotiation response phase, and the authentication key negotiation confirmation phase. The specific negotiation process is described below, and the flowchart is shown in the figure. Figure 1 As shown.

[0052] 1) The dual-mode communication unit T generates an application connection establishment message, which is an authentication key negotiation request message, and sends this message to the master station C. Table 1 shows the data structure of this message.

[0053] Table 1 Authentication Key Negotiation Request Message

[0054]

[0055]

[0056] The specific generation steps are as follows:

[0057] ① The dual-mode communication unit T selects a random number r1∈[1,n-1] and uses the public key of the dual-mode communication unit T to calculate U1=[r1]R T ;

[0058] ② Obtain the current timestamp t1 of the dual-mode communication unit T, and perform hash processing on message m1 and the current timestamp t1 (where m1 = Type||Subtype||ID) to obtain the message hash value.

[0059] ③ Use the system's publicly available parameters, the chip ID number of the dual-mode communication unit T, and the private key s T Perform the following operations: randomly select l1∈[1,n-1], R1=[l1]R T ,from Solution Sign1 = (R T U T ,U1,R1,s1) is the complete certificateless digital signature of message m1 by the dual-mode communication unit T.

[0060] ④ The dual-mode communication unit T sends the message M1=m1||t1||Sign1 to the master station C via the wireless channel.

[0061] 2) After receiving M1, the master station C first performs message parsing and signature verification, and then generates an authentication key negotiation response message with the message structure shown in Table 2.

[0062] Table 2 Key Negotiation Response Messages

[0063] < / g> < / g> name illustrate Type Message type Subtype Message Subtype MAC The main server's unique MAC address <![CDATA[t2]]> Timestamp <![CDATA[Sign2]]> sign

[0064] The specific steps for generating the master station authentication key negotiation request message and response message are as follows:

[0065] ① After receiving M1=m1||t1||Sign1, the main station C first parses the message, obtains the timestamp t1, and verifies the freshness of the request message (freshness means that the message content is complete and has not been changed). If the verification is successful, it proceeds to the next step; otherwise, it rejects the message.

[0066] ② The main station C inputs the system's public parameters and the public key (R) of the dual-mode communication unit T. T U T Information m1∈{0, l} * The hash values ​​L1 and Sign1 of timestamp t1 are (R T U T For each of the following pairs of units (U1, R1, s1), the following operation is performed: The signature is accepted and the dual-mode communication unit T is successfully authenticated if and only if the following equation is true:

[0067]

[0068] Established.

[0069] Correctness:

[0070]

[0071] ③The main station C selects a random number r2∈[1,n-1], and uses the public key of the main station C to calculate U2=[r2]R C .

[0072] ④ Obtain the current timestamp t2 of the main station, perform hash processing on messages m2 and t2 (where m2 = Type||Subtype||MAC), and obtain the message hash value.

[0073] ⑤ Use the system's public parameters and the private key s of the main station C. c Perform the following operations: randomly select l2∈[1,n-1], R2=[l2]R C ,from Solution Sign2 = (R C U C U2, R2, s2) is the complete certificateless digital signature of message m2 by the master station C.

[0074] ⑥ Main station C further calculates K 12 =U1v C r2, and obtain the temporary session key DK=K 12 =[v T v C r1r2]Q.

[0075] ⑦ The master station C sends the message M2=m2||t2||Sign2 to the dual-mode communication unit T via the wireless channel.

[0076] 3) After receiving M2, the dual-mode communication unit T first performs message parsing and signature verification, and then generates an authentication key negotiation confirmation message with the message structure shown in Table 3.

[0077] Table 3 Key Negotiation Confirmation Messages

[0078] name illustrate Type Message type Subtype Message Subtype ID Unique ID number of dual-mode communication chip <![CDATA[t3]]> Timestamp <![CDATA[Sign3]]> sign

[0079] The specific steps for processing the authentication key negotiation response message and generating the confirmation message are as follows.

[0080] ① After receiving M2=m2||t2||Sign2, the dual-mode communication unit 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, it rejects the message.

[0081] ② Input the system's public parameters and the public key PK of the main station C. C Information m2∈{0, l} * The hash values ​​L2 and Sign2 of timestamp t2 are related to (R). C U C For each of the following (U2, R2, s2), perform the following operations: accept the signature and successfully authenticate the dual-mode communication unit T if and only if the following equation applies:

[0082]

[0083] Established.

[0084] ③ The dual-mode communication unit T further calculates K. 21 =U2v T r1, and obtain the temporary session key DK=K 21 =[v T v C r1r2]Q.

[0085] ④ Obtain the current timestamp t3 of the dual-mode communication unit T, and process messages m3, t3, and the temporary session key K. 21 Perform hash processing (where m3 = Type||Subtype||ID) to obtain the message hash value. Calculate the digital signature Sign3 = [L3]G.

[0086] ⑤ The dual-mode communication unit T sends the message M3=m3||t3||Sign3 to the master station C via the wireless channel.

[0087] 4) After receiving M3, Master Station C obtains the timestamp t3 to verify the freshness of the acknowledgment message. If the verification is successful, proceed to the next step; otherwise, reject the message. The acknowledgment message is parsed, and the messages m3 and t3, along with the temporary session key K generated by Master Station C, are analyzed. 12 Perform hash processing to obtain the message hash value. Calculate the signature Sign'3 = [L'3]G; compare Sign'3 with Sign3 to see if they are equal. If they are equal, then both parties have authenticated each other's identity and hold the temporary session key DK. If they are not equal, the master station C will give a warning message that the authentication negotiation has failed and notify the dual-mode communication unit T to re-initiate the authentication key negotiation.

[0088] The safety of this method will be analyzed and explained from two aspects below.

[0089] 1) Replay Attack Resistance. A replay attack refers to an attacker intercepting a message request and subsequently using it to impersonate a legitimate user. The protocol uses timestamps t1, t2, and t3 in the authentication key negotiation request, response, and acknowledgment messages to prevent replay attacks. To pass authentication, the attacker must modify t1, t2, and t3 to a new timestamp consistent with the receiver's local clock. Once t1, t2, and t3 have been modified, Sign1, Sign2, and Sign3 must also be modified. However, since the attacker does not know the user's private key s... T s C And the selected random numbers r1, r2 and the temporary negotiation session key K 21 Therefore, attackers cannot obtain valid Sign1, Sign2, and Sign3. Thus, the protocol is resistant to replay attacks.

[0090] 2) Message Tampering Prevention. A tampering attack refers to an attacker intercepting a message request and modifying it to obtain a legitimate request message. In the authentication key negotiation protocol, signatures Sign1, Sign2, and Sign3 are used in the authentication key negotiation request, response, and acknowledgment messages to prevent message tampering attacks. An attacker, by intercepting a message, knows the corresponding messages m1, m2, m3 and their corresponding hash values ​​L1, L2, L3. To successfully tamper with messages M1, M2, and M3, the attacker must recalculate the signatures Sign1', Sign'2, and Sign'3 of the modified message m'. However, since the attacker does not know the user's private key s... T s C If s1' and s'2 cannot be successfully calculated, then signatures Sign1', Sign'2, and Sign'3 cannot be obtained, resulting in signature verification failure. Therefore, the protocol is resistant to message tampering attacks.

[0091] This invention applies a certificate-free authentication key negotiation protocol based on the elliptic curve discrete logarithm problem to a high-speed dual-mode communication system for smart grid electricity consumption information collection. It eliminates the necessity of traditional public key certificates in authentication key negotiation, removing the overhead of cumbersome operations caused by certificate management by the metering management center. This avoids the problems of high computational overhead, communication latency, storage space constraints, and high power consumption that arise in high-speed dual-mode communication systems for smart grid electricity consumption information collection. Furthermore, it is more efficient and simpler than bilinear pairing algorithms and outperforms traditional discrete logarithm systems.

[0092] System Implementation Example:

[0093] An embodiment of the electricity consumption information collection system of the present invention includes a dual-mode communication unit and a master station. The dual-mode communication unit and the master station are connected via a communication link. The dual-mode communication unit and the master station perform bidirectional authentication key negotiation using the bidirectional authentication key negotiation method described in the method embodiment. This method has been described in detail in the method embodiment and will not be repeated in this embodiment.

Claims

1. A two-way authenticated key agreement method, characterized by, The contents of the authentication key agreement request message, the authentication key agreement response message and the authentication key agreement confirmation message each include a message type, a message subtype, an ID of one party, a timestamp and a digital signature. 1) One party gets its current timestamp ; combining the system disclosure parameter, the ID of one party and the private key of one party, to generate the digital signature of one party to the message : , the public key of one party; , , , are all random numbers and n is the order; , is a selected cryptographic hash algorithm, is the result of hash processing to the message and the time stamp , is the private key of one party, and are respectively the x, y coordinates of the point on the elliptic curve, is the multiple point operation of ; and then according to and generate the authentication key agreement request message and send to the other party;​ 2) the other party acquires its current timestamp ; parses the received request message and verifies it, and after verification, generates the digital signature of the other party on the message , in combination with the system public parameter and the private key of the other party ; and ; and obtain a temporary session key ; and then according to and generate an authentication key agreement response message and send it to one party; 3) one side analyzes the received response message, and verifies , and obtains a temporary session key after successful verification ; Get its current timestamp ,according to Calculate one side of the message Digital signature ; and then according to and Generate an authentication key negotiation confirmation message and send it to the other party; ; For one party's private key; This is the other party's private key; , and All are random numbers and ; express The doubling operation; the key generation center is selected as the generation origin point in the elliptic curve. ; 4) the other party analyzes the received confirmation message and, according to the verification, if successful, considers that the two parties have authenticated each other's identity. the verification, if successful, considers that the two parties have authenticated each other's identity.

2. The bidirectional authentication key agreement method of claim 1, wherein, Elliptic curve For , a, b, x and y are in a finite field , and satisfy .

3. The bidirectional authentication key agreement method of claim 2, wherein, the digital signature generated in step 2 is: ; wherein is the public key of the other party; ; , is a random number and ; , is the result of hashing the message and the time stamp , is the private key of the other party, and are the x and y coordinates, respectively, of the point on the elliptic curve; denotes the multiple point operation of .

4. The bidirectional authentication key agreement method of claim 3, wherein, the digital signature generated in step 3 is: ; wherein is the result of hashing the message , the time stamp and the temporary session key .

5. The bidirectional authentication key agreement method of claim 4, wherein, If the digital signature is equal to the digital signature , then the digital signature is determined to be valid. Wherein, , is the result of hashing the message , the time stamp and the temporary session key .

6. The bidirectional authentication key agreement method according to any one of claims 1 to 5, characterized in that, The communication unit is one party of the mutual authentication key agreement, the host is the other party of the mutual authentication key agreement, and the communication unit and the host are configured to perform mutual authentication key agreement using the mutual authentication key agreement method according to any one of claims 1 to 6.

7. A power utilization information collecting system comprising a communication unit and a host station, characterized by ​

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