CN115776390A - MQTT protocol identity authentication and data encryption method based on state password - Google Patents

Abstract

The invention belongs to the technical field of MQTT protocol, and in particular relates to a national secret-based MQTT protocol identity authentication and data encryption method. The present invention uses the SM2 algorithm to digitally sign the ciphertext of the key K1, username, and password in the MQTT protocol, which not only achieves the effect of identity authentication, but also ensures the authenticity and non-repudiation of the data; Key data such as username, password, and topic messages are encrypted to increase data confidentiality and solve the problem of data leakage; the SM3 algorithm is used to ensure the integrity of topic messages in the MQTT protocol and prevent data from being illegally tampered with.

Description

A MQTT protocol identity authentication and data encryption method based on national secret

technical field

The invention belongs to the technical field of MQTT protocol, and in particular relates to a national secret-based MQTT protocol identity authentication and data encryption method.

Background technique

With the rapid development of the Internet of Things technology, the security of the Internet of Things is also facing severe challenges. MQTT is an IoT transmission protocol based on the publish/subscribe method under the ISO standard. It is suitable for IoT scenarios with low power consumption and limited network bandwidth because of its lightweight, simple, open and easy-to-implement features. In view of the lack of sufficient security protection mechanisms in the traditional MQTT protocol, it is of great significance to propose an effective MQTT protocol protection measure.

The National Secret Algorithm is a cryptographic algorithm standard and its application specification recognized and published by the Cryptography Administration of my country. It is a set of data encryption processing series algorithms independently developed by my country in the core field of cryptography. The national secret algorithms that have been promulgated include: symmetric encryption algorithm (SM1, SM4), asymmetric encryption algorithm (SM2, SM9), hash password algorithm (SM3), etc. The country is currently vigorously promoting the independent and controllable national secret algorithm. The popularization of the national secret algorithm is of great significance to improve the level of network information security and independent control in our country.

The MQTT (Message Queue Telemetry Transmission) protocol is a message transmission protocol based on the agent-based publish/subscribe mode, which belongs to the application layer protocol above the TCP/IP protocol. It has been widely used in many aspects such as smart medical care, smart home, and power equipment monitoring. The MQTT protocol has three roles: the subscriber, the publisher and the MQTT Broker. The subscriber and the publisher are collectively referred to as the client, and the MQTT Broker is the proxy server. The subscriber sends subscription topics to MQTT Broker; the publisher publishes topic content to MQTT Broker; MQTT Broker is responsible for forwarding messages. Since the data in the MQTT protocol is always transmitted in plain text during transmission, data security cannot be guaranteed. Therefore, the present invention uses the SM2 algorithm, the SM3 algorithm, and the SM4 algorithm to add the functions of identity authentication and data encryption to the MQTT protocol to solve the security problem of the MQTT protocol.

Contents of the invention

The purpose of the present invention is to provide a method for identity authentication and data encryption of the MQTT protocol based on national secrets.

A national secret-based MQTT protocol identity authentication and data encryption method, in the identity authentication stage, before the CONNECT packet is sent, the client first connects with the MQTT Broker;

The client randomly selects 16 bytes from its private key SK _c to form a set of numbers K1, encrypts K1 through the certificate public key PK _s of the MQTT Broker, and generates C1; sends the client certificate and C1 to the MQTT Broker;

MQTT Broker decrypts C1 with its own private key SK _s to obtain client information, and signs C1 with SK _s to generate σ1; set C1'=C1, and send C1' and σ1 to the client;

The client compares the received C1' with the local C1, and if they are exactly the same, it uses PK _s to verify the signature σ1; after the signature verification is passed, the client signs C1' with SK _c to generate σ2, and sends C1' and σ2 are sent to MQTTBroker;

MQTT Broker compares the received C1' with the local C1. If they are identical, the signature σ2 is verified by the client certificate public key PK _c ; the verification result is returned after the signature verification is passed, and K1 is the connection between the client and MQTT Broker The SM4 symmetric key;

The client first encrypts username and password to generate C _up ; then signs C _up with its own private key SK _c to generate σ _up , puts C _up and σ _up into the CONNECT packet and sends it to MQTT Broker;

After MQTT Broker receives the CONNECT packet, it first verifies the signature σ _up through the client certificate public key PK _c ; after the signature verification is passed, it decrypts the ciphertext C _up to obtain the username and password, and returns CONNACK to the client after the identity verification is passed.

Further, the client generates C1, σ1, σ2 and σ _up through the SM2 algorithm, and generates C _up through the SM4 algorithm.

Further, in the key key component acquisition phase, the client sends the Client _ID and the subscription topic Topic to the MQTT Broker; the MQTT Broker checks whether there is the same Topic locally; if there is no same Topic locally, it generates a Key _Topic , and then encrypts it through K1 Key _Topic , generate ciphertext C _KeyTopic , and send C _KeyTopic to the client; if there is the same topic locally, encrypt Key _Topic directly through K1, generate ciphertext C _KeyTopic and send it to the client.

Further, the MQTT Broker generates the Key _Topic through the SM3 algorithm, Key _Topic =H(Topic||K1||SK _s ), and generates the ciphertext C _KeyTopic through the SM4 algorithm, C _KeyTopic =E _K1 (KeyTopic).

Further, in the data transmission phase, the subscriber sends a SUBSCRIBE packet to the MQTT Broker to subscribe to the subject content;

The publisher generates a 16-byte random number R, and calculates H(R||Topic||Key _Topic ), uses the first 16 bytes of the hash value as the data encryption key Key, and encrypts the content corresponding to the Topic Encrypt to generate the ciphertext C _mess ; the content in the PUBLISH packet sent by the publisher to the MQTT Broker is PUBLISH(Topic,C _mess +R+H(C _mess ||R||Key _Topic ));

The subscriber calculates H(C _mess ||R||Key _Topic ) after receiving the PUBLISH packet forwarded by the MQTT Broker, and compares it with the H(C _mess ||R||Key _Topic ) in the received PUBLISH packet; If they are the same, calculate H(R||Topic||Key _Topic ), and take the first 16 bytes as the decryption key Key to decrypt the message C _mess , so far the plaintext of the message is obtained.

Further, the publishing end calculates H(R||Topic||Key _Topic ) through the SM3 algorithm, and generates the ciphertext C _mess through the SM4 algorithm; the subscriber calculates H(C _mess ||R||Key Topic through the SM3 algorithm _Topic ) and H(R||Topic||Key _Topic ).

The beneficial effects of the present invention are:

The present invention uses the SM2 algorithm to digitally sign the ciphertext of the key K1, username, and password in the MQTT protocol, which not only achieves the effect of identity authentication, but also ensures the authenticity and non-repudiation of the data; Key data such as username, password, and topic messages are encrypted to increase data confidentiality and solve the problem of data leakage; the SM3 algorithm is used to ensure the integrity of topic messages in the MQTT protocol and prevent data from being illegally tampered with.

Description of drawings

Fig. 1 is a flowchart of the present invention.

Fig. 2 is a sequence diagram of identity authentication in the present invention.

Fig. 3 is a sequence diagram of key key component acquisition and data transmission in the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In order to solve the data security problem of the MQTT protocol, the present invention adds functions of identity authentication and data encryption of the MQTT protocol. In the traditional MQTT protocol, MQTT Broker only authenticates the publisher/subscriber through username and password, but username and password are transmitted in plain text, which is easy to be illegally obtained by attackers. In addition, all interactive data in the MQTT protocol is transmitted in plain text, which has low security. In view of the above problems, the present invention proposes a MQTT protocol identity authentication and data encryption method based on the national secret algorithm.

The present invention is divided into three stages: an identity authentication stage, a key key component acquisition stage, and a data transmission stage. Specific steps are as follows:

1. Identity authentication stage. Add an identity authentication function before sending a message to ensure that the publisher and subscriber connected to the MQTT Broker are trustworthy.

1) Before the CONNECT packet is sent, the publisher and the subscriber (hereinafter referred to as the client) first connect to the MQTT Broker.

Step 1: The client randomly selects 16 bytes from its private key SK _c to form a set of numbers K1, encrypts K1 through the certificate public key PK _s of the MQTT Broker (SM2 algorithm) to generate C1, and converts the client certificate and C1 sends to MQTT Broker.

Step 2: MQTT Broker decrypts C1 with its own private key SK _s to obtain client information. Use SK _s to sign C1 to generate σ1 (SM2 algorithm), set C1'=C1, and send C1' and σ1 to the client.

Step 3: The client compares the received C1' with the local C1. If they are exactly the same, use PK _s to verify the signature σ1. After the signature verification is passed, the client uses SK _c to sign C1' to generate σ2( SM2 algorithm), send C1' and σ2 to MQTT Broker.

Step 4: The MQTT Broker compares the received C1' with the local C1. If they are identical, the signature σ2 is verified by the client certificate public key PK _c , and the verification result is returned after the signature verification is passed. K1 is the client and SM4 symmetric key between MQTTBrokers.

2) Send CONNECT packet

Step 5: The client first encrypts username and password (SM4 algorithm), that is, C _up = E _K1 (username&password)), and then signs C up with its own private key SK _c to generate _{σ up (} SM2 algorithm) to convert C _up and σ _up are put into the CONNECT packet and sent to MQTT Broker;

Step 6: After receiving the CONNECT packet, the MQTT Broker first verifies the signature σ _up through the client certificate public key PK _c , and after the signature verification is passed, decrypts the ciphertext C _up to obtain the username and password, that is, username&password=D _K1 (C _up ). Return CONNACK to the client after the authentication is passed.

2. The key key component acquisition stage. Since the MQTT Broker in the MQTT protocol only plays the role of forwarding messages and does not decrypt messages, the key key component acquisition phase enables the publisher and subscriber to obtain the same key key component for assembling the same SM4 symmetric key .

Step 7: Before sending the SUBSCRIBE data packet at the subscriber end and the PUBLISH data packet at the publisher end, the client sends the Client _ID and subscription topic Topic to the MQTT Broker.

Step 8: MQTT Broker checks whether there is the same Topic locally, if not, calculate Key _Topic = H(Topic||K1||SK _s ) (SM3 algorithm), and then encrypt Key _Topic (SM4 algorithm) through K1 to generate ciphertext C _KeyTopic = E _K1 (KeyTopic) sends C _KeyTopic to the client. If yes, then directly generate the ciphertext C _KeyTopic through K1 encryption Key _Topic (SM4 algorithm) and send it to the client.

Step 9: The subscriber receives and decrypts the ciphertext C _KeyTopic , that is, Key _Topic = D _K1 (C _KeyTopic ).

Third, the data transmission stage.

Step 10: The subscriber sends a SUBSCRIBE packet to the MQTT Broker to subscribe to the topic content.

Step 11: The publisher generates a 16-byte random number R, and calculates H(R||Topic||Key _Topic ) (SM3 algorithm), and uses the first 16 bytes of the hash value as the data encryption key Key , encrypt the content of the corresponding Topic to generate the ciphertext C _mess (SM4 algorithm), and the content in the PUBLISH packet sent by the publisher to the MQTT Broker is PUBLISH(Topic,C _mess +R+H(C _mess ||R|| Key _Topic )).

Step 12: After receiving the PUBLISH packet forwarded by the MQTT Broker, the subscriber calculates H(C _mess ||R||Key _Topic ) (SM3 algorithm), and compares it with the H(C _mess ||R ||Key _Topic ), if they are the same, calculate H(R||Topic||Key _Topic ) (SM3 algorithm) and take the first 16 bytes as the decryption key Key to decrypt the message C _mess . So far, the plain text of the message has been obtained.

Compared with the prior art, the beneficial effect of the present invention is: use the SM2 algorithm to digitally sign the ciphertexts of keys K1, username, and password in the MQTT protocol, which not only achieves the effect of identity authentication, but also ensures the authenticity of the data and non-repudiation; use the SM4 algorithm to encrypt key data such as username, password, and topic messages in the MQTT protocol, which increases data confidentiality and solves the problem of data leakage; uses the SM3 algorithm to ensure the security of topic messages in the MQTT protocol Integrity, preventing data from being tampered with illegally.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A MQTT protocol identity authentication and data encryption method based on national secrets, characterized in that: in the identity authentication stage, before the CONNECT packet is sent, the client is connected to the MQTT Broker earlier; The client randomly selects 16 bytes from its private key SK _c to form a set of numbers K1, encrypts K1 through the certificate public key PK _s of the MQTT Broker, and generates C1; sends the client certificate and C1 to the MQTT Broker; MQTT Broker decrypts C1 with its own private key SK _s to obtain client information, and signs C1 with SK _s to generate σ1; set C1'=C1, and send C1' and σ1 to the client; The client compares the received C1' with the local C1, and if they are exactly the same, it uses PK _s to verify the signature σ1; after the signature verification is passed, the client signs C1' with SK _c to generate σ2, and sends C1' and σ2 are sent to MQTTBroker; The MQTT Broker compares the received C1' with the local C1. If they are identical, the signature σ2 is verified by the client certificate public key PK _c ; the verification result is returned after the signature verification is passed, and K1 is the difference between the client and the MQTT Broker. SM4 symmetric key between; The client first encrypts username and password to generate C _up ; then signs C _up with its own private key SK _c to generate σ _up , puts C _up and σ _up into the CONNECT packet and sends it to MQTT Broker; After MQTT Broker receives the CONNECT packet, it first verifies the signature σ _up through the client certificate public key PK _c ; after the signature verification is passed, it decrypts the ciphertext C _up to obtain the username and password, and returns CONNACK to the client after the identity verification is passed. 2. A kind of MQTT protocol identity authentication and data encryption method based on national secret according to claim 1, it is characterized in that: described client generates C1, σ1, σ2 and σ _up by SM2 algorithm, generates C by SM4 algorithm _up . 3. The MQTT protocol identity authentication and data encryption method based on national secrets according to claim 1, characterized in that: in the key key component acquisition phase, the client sends Client _ID and subscription topic Topic to MQTT Broker; MQTT Broker checks whether there is the same topic locally; if there is no same topic locally, generate a Key _Topic , then encrypt the Key _Topic with K1, generate ciphertext C _KeyTopic , and send C _KeyTopic to the client; if there is the same topic locally, Then directly encrypt the Key _Topic through K1, generate the ciphertext C _KeyTopic and send it to the client. 4. A kind of MQTT protocol identity authentication and data encryption method based on national secret according to claim 3, it is characterized in that: described MQTT Broker generates Key _Topic by SM3 algorithm, Key _Topic =H(Topic||K1|| SK _s ), generate ciphertext C _KeyTopic through the SM4 algorithm, C _KeyTopic =E _K1 (KeyTopic). 5. The MQTT protocol identity authentication and data encryption method based on national secrets according to claim 1, characterized in that: in the data transmission stage, the subscriber sends a SUBSCRIBE data packet to the MQTT Broker to subscribe to the subject content; The publisher generates a 16-byte random number R, and calculates H(R||Topic||Key _Topic ), uses the first 16 bytes of the hash value as the data encryption key Key, and encrypts the content corresponding to the Topic Encrypt to generate the ciphertext C _mess ; the content in the PUBLISH packet sent by the publisher to the MQTT Broker is PUBLISH(Topic,C _mess +R+H(C _mess ||R||Key _Topic )); The subscriber calculates H(C _mess ||R||Key _Topic ) after receiving the PUBLISH packet forwarded by the MQTT Broker, and compares it with the H(C _mess ||R||Key _Topic ) in the received PUBLISH packet; If they are the same, calculate H(R||Topic||Key _Topic ), and take the first 16 bytes as the decryption key Key to decrypt the message C _mess , so far the plaintext of the message is obtained. 6. A kind of MQTT protocol identity authentication and data encryption method based on national secret according to claim 5, it is characterized in that: described publishing end calculates H(R||Topic||Key _Topic ) through SM3 algorithm, through SM4 The algorithm generates the ciphertext C _mess ; the subscriber calculates H(C _mess ||R||Key _Topic ) and H(R||Topic||Key _Topic ) through the SM3 algorithm.

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