Internet of Things equipment security access control method based on segmentation thought

Abstract

The invention discloses an Internet of Things equipment security access control method based on a segmentation thought, which is applied to the technical field of communication, and aims at solving the problem that a role-based flexible access control strategy and hardware protection measures of a traditional network are not suitable for data security and access control of the Internet of Things which takes light-weight equipment as a main part. According to the invention, through initial setting or operation of the proxy server, setting of a lightweight block cipher algorithm based on LBlock, and utilization of a segmentation idea, higher-level security protection is provided for the Internet of Things equipment, especially in an application scene requiring high security and lightweight, information is encrypted and is not tampered, confidentiality and integrity of the information are ensured, and the security of the Internet of Things equipment is improved. And information security is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and in particular relates to an Internet of Things communication security technology. Background Art

[0002] With the widespread application of big data and the Internet of Things, the scale and complexity of data are increasing, and data security and access control have become key issues. In the Internet of Things environment, access control and identity authentication are key technologies to ensure control security. By implementing strict access control policies, access rights to IoT devices and systems can be restricted to prevent unauthorized users or devices from operating key resources. At the same time, the use of strong cryptographic algorithms and secure identity authentication mechanisms can ensure the authenticity and credibility of device and user identities and prevent identity impersonation and forgery.

[0003] IoT security access control technology currently faces the challenge of being unable to implement the flexible role-based access control strategies and hardware protection measures of traditional networks. Although the security of IoT transmission and storage information can be improved by setting access control policies that prohibit access to unauthorized resources, the implementation of such strategies is still challenging. The use of secure hardware protection mechanisms can resist reverse analysis and unauthorized access, and is one of the effective security control measures for IoT. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a secure access control method for Internet of Things devices based on the idea of ​​segmentation. It mainly sets up a lightweight block cipher algorithm based on LBlock through initial settings or the operation of a proxy server, and uses the idea of ​​segmentation to provide a higher level of security protection for Internet of Things devices, especially in application scenarios that require high security and lightweight, so that information can be encrypted and cannot be tampered with, thereby ensuring the confidentiality and integrity of the information and ensuring information security.

[0005] The technical solution adopted by the present invention is: a method for secure access control of IoT devices based on the idea of ​​segmentation, the application scenarios include: client, proxy server, user; the client is denoted as o, the proxy server is d, and the user is s; the access control method includes the following steps:

[0006] S1, proxy server d generates a subscription instruction according to the instruction sent by user s, and uses the improved segmentation method to send the subscription instruction to client o;

[0007] S2, client o receives the information from proxy server d, processes it, and confirms the integrity of the information;

[0008] S3, client o publishes subscription data to proxy server d using the improved segmentation method according to the subscription instruction content;

[0009] S4. After receiving the information from client o, proxy server d sends the information that has passed the information security and information source reliability judgment to user s.

[0010] Beneficial effects of the invention: Compared with previous inventions, the present invention introduces restricted elements such as blacklists of users and devices, sensitive strings, data and other elements, further strengthening the functions of information encryption, signature authentication, and integrity verification. At the same time, it introduces the security level of users and devices, strengthens the access control level, thereby strengthening the information security assurance mechanism of the system, combining the LBlock lightweight block cipher algorithm and the key splitting idea. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a frame diagram of the proxy server involved in the present invention.

[0012] Figure 2 It is a specific flow chart of step 2-step 3 of a specific embodiment of the present invention.

[0013] Figure 3 It is a specific flow chart of step 4-step 5 of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0014] The purpose of the present invention is to provide a method for secure access control of Internet of Things devices that combines the LBlock lightweight block cipher algorithm and the key splitting idea for the link between the proxy server and the device in the user-proxy server-client Internet of Things environment framework. This method introduces the lightweight block cipher algorithm and the splitting idea, and aims to improve the security of Internet of Things devices and the flexibility of access control, and realize fast access between the proxy server and the device, and does not specifically involve a secure access control method between a user and a proxy server.

[0015] The LBlock lightweight block cipher algorithm is used to flexibly implement data encryption to improve the security of the system. The key splitting idea is adopted: it is achieved through physical separation, logical separation or a combination of the two. In this way, even if part of the key is leaked, the attacker cannot use these keys alone to decrypt the data because the keys of other parts are also needed. In the Internet of Things environment, the security access control method designed by the present invention can be applied to aspects such as device identity authentication and data access control. By combining the identity authentication and access control strategies of Internet of Things devices, it is ensured that only authorized devices can access sensitive data or perform key operations.

[0016] In order to achieve the above object, the technical solution of the present invention is: a method for secure access control of IoT devices based on the segmentation concept, comprising the following main steps:

[0017] Step 1. The proxy server d subscribes to the instruction from the client o;

[0018] Step 2. Client o receives the information from proxy server d and processes it;

[0019] Step 3. Client o publishes subscription data according to the subscription instruction content;

[0020] Step 4. After receiving the information from client o, proxy server d further determines the security of the information and the reliability of the information source.

[0021] To facilitate those skilled in the art to understand the technical content of the present invention, the present invention is further explained below with reference to the accompanying drawings.

[0022] The LBlock lightweight block cipher algorithm involved in the present invention refers to Wu Wenling, Zhang Lei's literature: Wu WL, Zhang L. LBlock: A lightweight block cipher [C] / / International Conference on Applied Cryptography and Network Security, 2011: 327-344.; Hughes key exchange algorithm and segmentation idea reference: Schleyer (USA), Wu Shizhong et al. Translated. Applied Cryptography: Protocols, Algorithms and C Source Programs [M]. Beijing: Machinery Industry Press, 2014.1.

[0023] 1.LBlock algorithm

[0024] The LBlock algorithm is a lightweight block encryption algorithm proposed by Wu Wenling and Zhang Lei at ACNS2011. Its block length is 64 bits, the key length is 80 bits, it is a 32-round iterative block algorithm, and adopts the Feistel algorithm structure. The encryption algorithm and decryption algorithm are mutually inverse, and the order of the round keys used is opposite. Secondly, the key expansion algorithm is originally designed, using the Feistel structure and SPN structure.

[0025] 2Hughes Key Exchange Algorithm

[0026] The Hughes key exchange algorithm is a variation of the Diffie-Hellman key exchange algorithm that allows Alice to generate a key and send it to Bob. Let p be a large prime number, g be the primitive root of p, and p and g be public global elements.

[0027] (1) Alice selects a large random integer x and generates k = g x mod p;

[0028] (2) Bob selects a large random integer y and sends it to Alice: Y = g y mod p;

[0029] (3) Alice sends to Bob: X = Y x mod p;

[0030] (4) Bob calculates z = y -1 , k'=X z mod p

[0031] After calculating k=k', Alice and Bob can share the key.

[0032] The present invention uses the Hughes key exchange algorithm to realize key sharing between the proxy server d and the client o, and generates two shared keys K-do1 and K-do2 which are alternately used for encryption and decryption keys of the LBlock algorithm and shared keys for data segmentation.

[0033] 3. Split Thought

[0034] Split idea: A splits message M to B and C as follows:

[0035] (1) A generates a random bit string R, which is the same length as the message M;

[0036] (2) A uses R XOR with M to obtain S: M⊕R=S;

[0037] (3) A gives R to B and S to C;

[0038] (4) B and C can reconstruct the message by XORing the messages they obtained: R⊕S=M.

[0039] In order to adapt to the characteristics that most clients are lightweight devices, the present invention improves this method to realize information transmission between the proxy server d and the client o. The improved method is as follows:

[0040] Improved splitting idea: A splits the message M||cert(J) with the certificate cert(J) to B. A has the certificate cert(J), and A and B share the shared key K. The method is as follows:

[0041] (1) A generates a random bit string R, which is the same length as the message M||cert(J) and K. If the three numbers are not the same length, the method of adding a number of zeros in front of the shorter one or two numbers is adopted to make the three numbers the same length;

[0042] (2) A uses R to XOR M||cert(J) to obtain S: (M||cert(J))⊕R=S;

[0043] (3) A XORs R with K to obtain W: R⊕K=W, and A gives both S and W to B;

[0044] (4) After receiving S and W, B can reconstruct the message by XORing them with the shared key:

[0045] S⊕W⊕K=((M||cert(J))⊕R)⊕(R⊕K)⊕K=M||cert(J)

[0046] By keeping K confidential, the random number R can ensure the confidentiality of information transmission, while verifying A's certificate to confirm that the information comes from A.

[0047] The present invention uses this improved split encryption for the access control process of lightweight devices. As an encryption method, by dividing information into multiple parts, each part can be encrypted using a different encryption key, which increases the difficulty for attackers to crack information. This encryption method not only improves the security of information transmission, but also increases the security of information. Through the split encryption, even if part of the information is intercepted, it is difficult for attackers to infer the content of the overall information through the part of the information, thereby protecting the integrity and privacy of the information. In addition, in the present invention, the split encryption is combined with the symmetric encryption algorithm LBlock algorithm to further improve the security of the information. Such an encryption method reduces the security risk on the key to a certain extent and improves the concealment of information transmission; after using this improved split encryption, its calculation amount only increases by two XOR operations. Since the XOR operation only involves the comparison of two input values, its calculation complexity is relatively low, and it has little effect on the processing efficiency and resource occupancy of the lightweight device; compared with the access control process of the lightweight device that does not use the split encryption, a small amount of processing efficiency and resource occupancy are sacrificed in exchange for higher security of the access control process.

[0048] According to the computer information system security protection level classification criteria of my country (GB 17859-1999), security level assessment is carried out on them respectively, and the relevant security elements involved are initially assessed and set. The relevant concepts and symbols are as follows:

[0049] Suppose the security level of client o is denoted as: T(o); the set of users that o restricts access is denoted as: os-limit() (user blacklist set); the set of instruction keywords that o does not allow subscription is denoted as: os-ins-limit() (sensitive string blacklist set), and apply for user certificate cert(o) from proxy server d.

[0050] Suppose the security level of user s is denoted as: T(s), the set of devices o that s restricts access to is denoted as: so-limit() (device blacklist set), the set of published data keywords that s is not allowed to accept is denoted as: so-ins-limit(), and apply for user certificate cert(s) from proxy server d.

[0051] The proxy server's certificate is: cert(d).

[0052] For the sake of simplicity, the present invention selects E and D to refer to the corresponding encryption and decryption algorithms respectively; the shared keys of the proxy server d and the client o are recorded as K-do1 and K-do2.

[0053] When the communicating parties transmit information, they set: t represents the timestamp of each party sending or receiving information, and set the interval of the data received by the sender and the receiver to not exceed Δt, that is, as long as the time interval is within Δt, it is considered that the data transmission has failed or has been attacked by replay. The setting of Δt depends on the transmission delay, propagation delay, processing delay, queuing delay and other factors of the specific transceiver equipment. Take the example of a proxy server transmitting data to a client. If the file size is 1MB and the transmission rate is 1Mbps, the transmission delay = (1MB*8) / 1Mbps = 8ms. Assuming that the data transmission path is 1000 kilometers long and the propagation rate is twice the speed of light (approximately 6*10^8 meters / second), the propagation delay = 1000000 meters / 6*10^8 meters / second = 1.67ms. Assuming that the processing delay and queuing delay are 2ms each, the delay for the proxy server to transmit data to the client is 8+1.67+2+2=13.67ms. Further analyzing the possible delay in transmitting data from the client to the proxy server, assuming it is 12.67ms, the maximum value of the two delays, 13.67ms, is taken as Δt.

[0054] The present invention will be further described below in conjunction with the accompanying drawings. Figure 1 As shown in the figure, it is a proxy server-based IoT transmission framework. The client-user is s, the proxy server is d, and the client-device is o. The following are respectively: Figure 1-3 The steps involved are described below:

[0055] Step 1. Initialize user s, proxy server d, and client o:

[0056] Step 11. Use the public Hughes key exchange algorithm to calculate the shared keys K-do1 and K-do2 between the proxy server d and the client o;

[0057] Step 12. Evaluate the various security factors of customer o, including: T(o), os-limit(), os-ins-limit(), cert(o), where the certificate content includes its own ID, etc.

[0058] Step 13. Evaluate the various security factors of user s, including: T(s), so-limit(), so-ins-limit(), cert(s), where the certificate content includes the user's ID, etc.

[0059] The present invention does not specifically discuss the access control method between the user and the proxy server. The following only involves the security access control method between the proxy server d and the client o. The relevant information of the user s will be used in the later process.

[0060] Step 2. Proxy server d subscribes to instruction {$so} from client o, see Figure 2 Left part.

[0061] The proxy server d subscribes to instructions from the client o and uses the aforementioned improved segmentation idea to transfer data.

[0062] Step 21. The proxy server d encrypts the subscription instruction {$so} to the client o using the LBlock algorithm to form E K-do1 {$so}.

[0063] Step 22. The proxy server d selects a random number R and sets E K-do1 {$so}, proxy server d subscribes to client o with the instruction {$so}, proxy server d subscribes to client o with the instruction timestamp t3, strung together: E K-do1 ({$so})||cert(d)||t3||({$so})) is denoted as M. Compare the number of digits of M, R and K-do2 (d and o share the key 2). If the lengths are different, fill the front of the one or both with fewer digits with several 0s to make the three digits consistent.

[0064] Step 23. Calculate (E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R, R⊕K-do2 are sent to customer o at the same time.

[0065] Here we mainly consider that most of the clients o are lightweight; no complex calculations are used, only the random number R generated by the proxy server d, known by the proxy server d and the client o, and the shared keys K-do1 and K-do2 are used for encryption and XOR to ensure the confidentiality of information; using E K-do1 ({$so}), cert(d) ensures that the information comes from a reliable source, from proxy server d;

[0066] Step 3. Client o receives the information from proxy server d and processes it. Figure 2 right part;

[0067] Step 31. Record the timestamp when client o receives the data sent by proxy server d as t4;

[0068] Step 32. Based on the received result {E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R, R⊕K-do2, calculation: {E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R}⊕{R⊕K-do2}⊕K-do2; restore (E K-do1 ({$so})||cert(d)||t3||({$so}));

[0069] Step 33. According to the result of step 32, determine the time: if t4>t3+Δt, the access is interrupted;

[0070] Step 34. Based on the results of step 32, use E K-do1 ({$so}) algorithm, key K-do1 decryption D K-do1 (E K-do1 ({$so})) get $so;

[0071] Step 35. Compare the result $so of step 34 with the result $so of step 32. If they are inconsistent, the access is interrupted.

[0072] Step 36. According to cert(d) in the result recovered in step 32, and the shared keys K-do1 and K-do2 between the proxy server d and the client o, confirm whether the information comes from d; if not, the access is interrupted; after steps 35 and 36, it can be confirmed whether the information is complete;

[0073] Step 4. Client o publishes subscription data $os according to the content of $so. For details, see Figure 3 Left part.

[0074] Client o publishes subscription data to proxy server d, and uses the aforementioned improved segmentation idea to transfer data.

[0075] Step 41. Client o generates subscription data $os according to the content of $so;

[0076] Step 42. Generate subscription instructions and security instruction set {$os, SE-o}, where SE-o = {cert(o), T(o), os-limit(), os-ins-limit()};

[0077] Step 43. Encrypt with the LBlock algorithm, key K-do2 to encrypt $os||cert(o) and get E K-do2 ($os||cert(o));

[0078] Step 44. Client o selects a random number R1 and concatenates the results of steps 42 and 43 together {$os,SE-o}||E k3 ($os||cert(o))||t5 (t5 is the timestamp when o issues the data $os instruction), recorded as Q, compare the number of bits of Q, R1 and K-do. If the lengths are different, fill the front of the one with fewer bits with several 0s to make the number of bits of the three consistent;

[0079] Step 45. Calculate ({$os,SE-o}||E K-do2 ($os||cert(o))||t5)⊕R1, R1⊕K-do1 (XOR calculation);

[0080] Step 46. Send proxy server d at the same time;

[0081] Step 5. After receiving the information from client o, proxy server d determines the source and reliability of the information, such as Figure 3 Right part.

[0082] Step 51. Record the timestamp when the proxy server d receives the data sent by the client o as t6;

[0083] Step 52. XOR the result received from client o with K-do1, and calculate {({$os,SE-o}||E K-do2 ($os||cert(o))||t5)⊕R1}⊕{R1⊕K-do1}⊕K-do1 gets {$os,SE-o}||E k-do2 ($os||cert(o))||t5;

[0084] Step 53. According to the time information obtained in step 52, determine the timestamp: if t6>t5+Δt, the access is interrupted;

[0085] Step 54. According to step 52E k-do2 ($os||cert(o)), decrypt D K-do2 (E k-do2 ($os||cert(o))) gets: $os||cert(o);

[0086] Step 55. According to step 52, obtain cert(o) in the security element set SE-o of client o. The cert(o) in step 54 is authentic and the message comes from o, ensuring that the information source is reliable. If it is unreliable, the access is interrupted.

[0087] Step 56. Compare the $os obtained in step 52 with the $os in step 54 to determine whether the contents are consistent and ensure that the information is complete; if not, the access is interrupted;

[0088] Step 57. According to the initialization results of step 42 and step 13, check the security parameter sets of user s and client o (wherein the relevant security parameters of user s are transmitted to proxy server d through the previous data transmission link from user s to proxy server d. The specific security transmission process is not discussed in the present invention and is omitted), check the release instruction and the release data content, and perform the following operations:

[0089] Step 571. Compare T(s) and T(o). If the security levels of the two do not satisfy T(s) ≥ T(o), the security level is insufficient and the access is interrupted (since there is no security factor set of client o stored in the proxy server before, the judgment is made only after client o transmits information to the proxy server d);

[0090] Step 572. Determine whether user s is a restricted user of client o, if s∈os-limit(), access is interrupted;

[0091] Step 573. Determine whether the instruction $so issued by user s is a set of instruction keywords that client o does not allow user s to issue, such as $so∈os-ins-limit(), and the access is interrupted;

[0092] Step 574: Determine whether client o is in the blacklist device set of user s, if o∈so-limit(), access is interrupted;

[0093] Step 575. Determine whether the subscription data published by client o is in the subscription data that user s does not allow client o to publish, such as $os∈so-ins-limit(), and the access is interrupted;

[0094] After the above operations, the $os received by the proxy server d is the security data that meets the subscription instruction conditions and has the characteristics of reliable information source, no leakage, and complete information.

[0095] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for secure access control of IoT devices based on segmentation, characterized in that: The application scenario includes: client, proxy server, user; the client is denoted as o, the proxy server is denoted as d, and the user is denoted as s; the access control method includes the following steps: S1, proxy server d generates a subscription instruction according to the instruction sent by user s, and uses the improved segmentation method to send the subscription instruction to client o; S2, client o receives the information from proxy server d, processes it, and confirms the integrity of the information; S3, client o publishes subscription data to proxy server d using the improved segmentation method according to the subscription instruction content; S4. After receiving the information from client o, proxy server d sends the information that has passed the information security and information source reliability judgment to user s.

2. According to claim 1, a method for secure access control of IoT devices based on segmentation concept is characterized in that: The implementation process of the proxy server d using the improved segmentation method to send a subscription instruction to the client o in step S1 includes the following steps: A1. The proxy server d encrypts the subscription instruction {$so} sent to the client o using the LBlock algorithm to form E K-do1 {$so}; A2. E K-do1 {$so}, proxy server d subscribes to client o {$so}, timestamp t3 of proxy server d subscribes to client o, strung together: E K-do1 ({$so})||cert(d)||t3||({$so})) is denoted as M. The proxy server d selects a random number R and compares the number of digits of M, R and K-do2. If the lengths are different, the longest data is used as the standard. The remaining data is padded with 0 to make the three digits consistent. cert(d) is the certificate of the proxy server d, and K-do2 is the shared key between the proxy server d and the client o. A3. Calculate (E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R, R⊕K-do2, and the calculation results are sent to client o at the same time; ⊕ is the exclusive OR symbol.

3. According to claim 2, a method for secure access control of IoT devices based on segmentation concept is characterized in that: In step S2, customer o receives the result {E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R, R⊕K-do2, calculation: {E K-do1 ({$so})||cert(d)||t3||({$so}))⊕R}⊕{R⊕K-do2}⊕K-do2; restore (E K-do1 ({$so})||cert(d)||t3||({$so})).

4. According to claim 3, a method for secure access control of IoT devices based on segmentation concept is characterized in that: The process of confirming the integrity of information in step S2 is as follows: According to the recovered result, decrypt D with key K-do1 K-do1 (E K-do1 ({$so}))get{$so}; The decrypted {$so} is compared with the {$so} in the restored result. If they are consistent, it means that the information received by client o is complete, and then step S3 is executed; otherwise, the access is interrupted.

5. According to claim 4, a method for secure access control of IoT devices based on segmentation concept is characterized in that: In step S3, the implementation process of client o using the improved segmentation method to publish subscription data to proxy server d includes the following steps: B1. Customer o generates subscription data $os based on the content of {$so}; B2. Generate subscription instructions and security instruction set {$os, SE-o}, where SE-o = {cert(o), T(o), os-limit(), os-ins-limit()}; cert(o) is the certificate that client o applies for from proxy server d, T(o) is the security level of client o, os-limit() is the set of users that client o is restricted from accessing, and os-ins-limit() is the set of instruction keywords that client o is not allowed to subscribe to; B3. Use the LBlock algorithm to encrypt $os||cert(o) with the key K-do2, and get E K-do2 ($os||cert(o)); B4. Client o selects a random number R1 and concatenates the results of steps B2 and B3 together {$os,SE-o}||E k3 ($os||cert(o))||t5, denoted as Q, compare the number of bits of Q, R1 and K-do. If the lengths are different, the data with the longest number of bits shall prevail, and the remaining data shall be padded with 0 to make the number of bits of the three consistent; t5 is the timestamp when client o issues the data $os instruction; B5. Calculate ({$os,SE-o}||E K-do2 ($os||cert(o))||t5)⊕R1, R1⊕K-do1; and send the calculation results to the proxy server d at the same time.

6. According to claim 5, a method for secure access control of IoT devices based on segmentation concept is characterized in that: The process of determining the reliability of the information source in step S4 includes the following steps: C1. XOR the result received from client o with K-do1, and calculate {({$os,SE-o}||E K-do2 ($os||cert(o))||t5)⊕R1}⊕{R1⊕K-do1}⊕K-do1 gets {$os,SE-o}||E k-do2 ($os||cert(o))||t5; C2. E obtained according to step C1 k-do2 ($os||cert(o)), decrypt D K-do2 (E k-do2 ($os||cert(o))) gets: $os||cert(o); C3. Perform identity authentication based on the cert(o) in the security element set SE-o obtained in step C1 and the cert(o) in step 54. If the identity is authentic, the message source is reliable; otherwise, access is interrupted.

7. According to claim 6, a method for secure access control of IoT devices based on segmentation concept is characterized in that: The determination of information security in step S4 includes the following: Compare the $os obtained in step C1 with the $os in step C2. If the contents are consistent, the information is complete. Otherwise, the access is interrupted; Check the security parameter set of user s and client o in the proxy server d, including: security level judgment, access restriction judgment, and sensitive character judgment; The security level is judged as follows: if T(s) ≥ T(o), the security level is considered to meet the requirements, otherwise the access is interrupted, and T(s) is the security level of user s; The specific judgment of restricted access is: if s∈os-limit(), user s is a restricted user of customer o, and the access is interrupted, otherwise the access is normal; if o∈so-limit(), customer o is a restricted user of user s, and the access is interrupted, otherwise the access is normal; The specific judgment of sensitive characters is: if $so∈os-ins-limit(), the instruction $so published by user s is the content of the instruction keyword set that customer o is not allowed to subscribe to, and the access is interrupted. Otherwise, the access is normal; if $os∈so-ins-limit(), the subscription data published by customer o is the content of the published data keyword set that user s is not allowed to accept, and the access is interrupted. Otherwise, the access is normal.

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