A key agreement method, device and communication system based on a preset key group

Abstract

This invention discloses a key negotiation method, apparatus, and communication system based on a pre-set key group, belonging to the field of information security. It includes: two parties exchanging keys via DH to generate a session key component, combining it with a PSK to generate the final session key; using the session key for encryption and decryption operations during communication; and a session deletion phase after communication, where both parties clear the used pre-set key. This invention employs a combination of conventional key exchange protocols and pre-set key components for key negotiation to obtain the transmission session encryption key. Each session requires a different pre-set key component (PSK), which is deleted after use, ensuring "one key per session," effectively improving forward security, exhibiting good anti-attack performance, and being suitable for communication networks with high security requirements.

Description

Technical Field

[0001] This invention belongs to the field of information security, and more specifically, relates to a key negotiation method, apparatus and communication system based on a pre-set key group. Background Technology

[0002] With the globalization of information technology and the emergence and development of digital communication systems, human society has undergone tremendous changes. Before two devices in a digital communication system need to exchange data, a secure communication mechanism is required to ensure the security of the exchanged data. This is typically achieved by using session keys to encrypt and decrypt the content to be communicated.

[0003] In existing technologies, keys obtained through conventional key exchange protocols cannot guarantee that unauthorized users cannot deduce the application keys used by the device directly from the device's internal information or deduce them from intercepted information after the device is out of control. This would allow them to decipher encrypted business information intercepted from the communication link in advance. Such technologies do not take into account high security and pose a risk of data leakage. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a key negotiation method, apparatus and communication system based on a pre-set key group, which aims to solve the problem that the existing methods do not take into account high security and have the risk of leakage.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a key negotiation method based on a pre-set key group. This method is applied at the negotiation initiating end, where multiple known PSK sets are pre-stored by both parties and an index is generated. The method includes:

[0006] S1. Encapsulate the IKE encryption and authentication algorithms it supports, random numbers, DH key exchange materials, and PSK index into a first message and send it to the negotiation response end;

[0007] S2. Receive and parse the second message sent by the negotiation response end, exchange the Nonce and DH algorithm, and generate a shared key;

[0008] S3. Encrypt its own identity, public key certificate and authentication data using a shared key, encapsulate the encrypted data into a third message and send it to the negotiation response end;

[0009] S4. Receive and parse the fourth message sent by the negotiation response end, decrypt it using the shared key, and after authentication, generate a session key based on the shared key and PSK;

[0010] S5. During communication, a session key is used for encryption and decryption. After communication ends, the used PSK is cleared.

[0011] Preferably, if the heartbeat message transmission times out, the passive session deletion process is triggered to clear the used PSK.

[0012] Preferably, the shared key and the PSK are XORed to generate the session key.

[0013] To achieve the above objective, in a second aspect, the present invention provides a key negotiation method based on a pre-set key group. This method is applied at a negotiation response end, wherein the negotiation response end pre-stores multiple known PSK sets between the two parties and generates an index. The method includes:

[0014] T1. Receive and parse the first message sent by the negotiation initiator, exchange Nonce and DH algorithm, and generate a shared key;

[0015] T2. Encapsulate the IKE encryption and authentication algorithms it supports, random numbers, and DH key exchange materials into a second message and send it to the negotiation initiator;

[0016] T3. Receive and parse the third message sent by the negotiation initiator, decrypt it using the shared key, and generate a session key based on the shared key and PSK after authentication;

[0017] T4. Encrypt its own identity, public key certificate, and authentication data using a shared key, encapsulate the encrypted data into a fourth message, and send it to the negotiation initiator.

[0018] T5. During communication, a session key is used for encryption and decryption. After communication ends, the used PSK is cleared.

[0019] Preferably, if the heartbeat message transmission times out, the passive session deletion process is triggered to clear the used PSK.

[0020] Preferably, the shared key and the PSK are XORed to generate the session key.

[0021] To achieve the above objectives, in a third aspect, the present invention provides a key negotiation device based on a preset key group, comprising: a processor and a memory;

[0022] The memory is used to store computer-executed instructions;

[0023] The processor is configured to execute the computer execution instructions to cause the apparatus to perform the method as described in any of the first aspects, and / or the method as described in the second aspect.

[0024] To achieve the above objectives, in a fourth aspect, the present invention provides a communication system based on a pre-set key group, comprising: a protocol initiator and a protocol response end;

[0025] The protocol initiator runs the method described in the first aspect;

[0026] The protocol response end runs the method described in the second aspect.

[0027] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0028] This invention proposes a key negotiation method, apparatus, and communication system based on a pre-set key group. It uses a combination of conventional key exchange protocol and pre-set key components to negotiate the key and obtain the encryption key for the transmission session. Each session requires a different pre-set key component, which is deleted after use to ensure "one key per session". This improves forward security and has good anti-attack performance, making it suitable for communication networks with high security requirements. Attached Figure Description

[0029] Figure 1 The present invention provides a flowchart of a key negotiation method based on a preset key group.

[0030] Figure 2 This is a schematic diagram of a communication system based on a preset key group, provided as an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram of the protocol interaction process for key negotiation between the modules of both parties, provided in an embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] like Figure 1 As shown, the present invention provides a key negotiation method based on a preset key group, the method comprising the following steps:

[0034] The initiator initiates message one, which carries the IKE (Network Key Exchange Protocol) encryption and authentication algorithm supported by the initiator, the initiator's random number, DH (Key Exchange Protocol / Algorithm, Diffie-Hellman) key exchange material, and the PSK (pre-shared key) index negotiated in this round.

[0035] The responder responds with message two, which carries the IKE encryption and authentication algorithms supported by the responder, the responder's random number, and DH key exchange materials.

[0036] Message 1 and Message 2 negotiate the cryptographic algorithm, exchange Nonce (Number once) and DH algorithm, and generate a shared key. Subsequent messages use this shared key to derive IKE encryption / authentication keys for subsequent IKE message encryption and integrity protection.

[0037] The initiator sends message three, which carries the initiator's identity identifier, initiator's public key certificate, and initiator's authentication data, and uses a shared key for encryption and integrity protection.

[0038] The respondent's response message four carries the respondent's identity identifier, the respondent's public key certificate, and the respondent's authentication data, and uses a shared key for encryption and integrity protection.

[0039] Messages three and four exchange public key certificates and identity identifiers to authenticate each other. Upon successful authentication, a session key is derived based on the shared key and PSK for use by IPSEC (Internet Protocol Security), and an IPSEC tunnel is created.

[0040] The methods for deriving session keys include, but are not limited to: using the shared key as key component one, using the PSK (pre-shared key) allocated in this round of negotiation as key component two, and performing an XOR operation on component one and component two to synthesize a final session key.

[0041] like Figure 2 As shown, in this embodiment, the participants in the key negotiation protocol include communication devices A and B. Communication device A is the initiator of the key negotiation, and communication device B is the responder. The protocol elements include communication devices A and B, the encryption algorithm, and the encryption key, and are rolled forward once after each negotiation.

[0042] like Figure 2 As shown, each communication device consists of a service processing unit, a cryptographic management unit, and a cryptographic operation unit. The service processing unit is used for processing data and control messages; the cryptographic management unit is used for cryptographic resource management, specifically, pre-storing N sets of PSKs and generating an index; and the cryptographic operation unit is used for message encryption and decryption.

[0043] The protocol interaction process for key negotiation between modules is as follows: Figure 3 As shown.

[0044] like Figure 3As shown, the service processing unit of communication device A requests a PSK index from the cryptographic management unit, which then issues the PSK index for this round of negotiation. The service processing module encapsulates the first packet (SAi, KEi, Ni, psk_index) and sends it to communication device B. Upon receiving the first negotiation packet, the service processing module of communication device B parses it and generates a shared key, while simultaneously encapsulating a second packet (Sar, KEr, Nr) and sending it back to communication device A. Upon receiving the second negotiation packet, the service processing module of communication device A parses it and generates a shared key, while simultaneously requesting a private key signature from the cryptographic management unit and receiving the returned private key signature result. The service processing module then encapsulates a third packet (Idi, CERTi, AUTHI) and encrypts and protects its integrity using the shared key before sending it to communication device B. After receiving and parsing the third negotiation packet, the service processing module of communication device B decrypts and verifies it. Upon successful verification, it sends the parsed private key signature of device A to the cryptographic management unit, requesting public key verification. Once verification is successful, the identity of communication device A is verified. At this point, the service processing module of communication device B sends the shared key and PSK index to the key management unit, which generates the final session key and distributes it to the cryptographic operation unit. Similarly, communication device B also requests a private key signature and receives the returned signature result. Simultaneously, its service processing module encapsulates the fourth packet (IDr, CERTR, AUTHr) and encrypts and protects its integrity using the shared key before replying to communication device A. After receiving and parsing the fourth negotiation packet, the service processing module of communication device A decrypts and verifies it. Upon successful verification, it sends the parsed private key signature of communication device B to the cryptographic management unit, requesting public key verification. Once verification is successful, the identity of communication device B is also verified. At this point, the service processing module of communication device A sends the shared key and PSK index to the key management unit, which generates the final session key and distributes it to the cryptographic operation unit. At this point, the cryptographic operation modules of communication devices A and B have both received the final generated session key. In subsequent communication processes, the cryptographic operation modules of both parties will use this session key to perform IPSec tunnel encryption and decryption operations.

[0045] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of key agreement based on a pre-set group of keys, characterized in that, This method is applied to the negotiation initiator, which pre-stores multiple known PSKs between the two parties and generates an index. The method includes: S1. Encapsulate the IKE encryption and authentication algorithms it supports, random numbers, DH key exchange materials, and PSK index into a first message and send it to the negotiation response end; S2. Receive and parse the second message sent by the negotiation response end, exchange the Nonce and DH algorithm, and generate a shared key; S3. Encrypt its own identity, public key certificate and authentication data using a shared key, encapsulate the encrypted data into a third message and send it to the negotiation response end; S4. Receive and parse the fourth message sent by the negotiation response end, decrypt it using the shared key, authenticate it, and then XOR the shared key and PSK to generate a session key; S5. During communication, a session key is used for encryption and decryption. After communication ends, the used PSK is cleared.

2. The method of claim 1, wherein, If the heartbeat message transmission or reception times out, the passive session deletion process is triggered to clear the PSK that has already been used.

3. A method of key agreement based on a pre-set key group, characterized by, This method is applied to the negotiation response end, which pre-stores multiple sets of PSKs known to both parties and generates an index. The method includes: T1. Receive and parse the first message sent by the negotiation initiator, exchange Nonce and DH algorithm, and generate a shared key; T2. Encapsulate the IKE encryption and authentication algorithms it supports, random numbers, and DH key exchange materials into a second message and send it to the negotiation initiator; T3. Receive and parse the third message sent by the negotiation initiator, decrypt it using the shared key, authenticate it, and then XOR the shared key and PSK to generate a session key; T4. Encrypt its own identity, public key certificate, and authentication data using a shared key, encapsulate the encrypted data into a fourth message, and send it to the negotiation initiator. T5. During communication, a session key is used for encryption and decryption. After communication ends, the used PSK is cleared.

4. The method of claim 3, wherein, If the heartbeat message transmission or reception times out, the passive session deletion process is triggered to clear the PSK that has already been used.

5. A key negotiation device based on a preset key group, characterized in that, include: Processor and memory; The memory is used to store computer-executed instructions; The processor is configured to execute the computer execution instructions to cause the device to perform the method as claimed in claim 1 or 2, and / or the method as claimed in claim 3 or 4.

6. A communication system based on a set of preset keys, characterized in that include: Protocol initiator and protocol responder; The method described in claim 1 or 2 is run on the protocol initiator. The protocol response terminal runs the method described in claim 3 or 4.

Images