IPSec VPN security gateway communication method fused with post quantum cryptography technology

Abstract

The invention discloses an IPSec (Internet Protocol Security) VPN (Virtual Private Network) security gateway communication method fused with a post quantum cryptography technology, which comprises the following steps of: S1, in a first-stage main mode of IKE (Internet Key Exchange) key agreement, replacing a traditional single SM2 algorithm and a digital certificate based on an SM2 cryptographic algorithm with an SM2 and PQC mixed algorithm and a mixed PQC digital certificate; s2, the initiator and the responder respectively use the PQC encryption key pair and the PQC signature key pair to carry out key exchange and data signature, and simultaneously use the SM2 encryption key pair and the SM2 signature key pair to carry out key exchange and data signature; s3, in the message 1, the initiator sends a security alliance load containing the attribute of the fused SM2 and PQC algorithm to the responder; s4, in the message 2, the responder feeds back a PQC series hybrid certificate and an SA proposal; and S5, in the message 3 and the message 4, the initiator and the responder complete key exchange and verification. According to the invention, the security of the IPSec VPN security gateway can be improved, and quantum computing attacks can be resisted.

Description

Technical Field

[0001] The present invention relates to the field of network security technology, and in particular to an IPSec VPN security gateway communication method integrating post-quantum cryptography technology. Background Art

[0002] Most classic IPSec VPN security gateway products are developed in accordance with GM / T 0022 "IPSec VPN Technical Specifications" and GM / T0023 "IPSec VPN Gateway Product Specifications". The digital certificates used comply with GM / T 0015 "Digital Certificate Format Specification Based on SM2 Cryptographic Algorithm" and support SM1, SM2, SM3 and SM4 algorithms. Among them, the SM2 cryptographic algorithm is used for identity authentication and key negotiation of network entities at both ends, the SM3 algorithm is used for data summary operations, and the SM1 and SM4 algorithms are used for data encryption and decryption.

[0003] GM / T 0022 "IPSec VPN Technical Specifications" states that IKE consists of two phases: the main mode in the first phase and the quick mode in the second phase. The main mode implements identity authentication and key exchange between the two communicating parties to obtain a working key, which is used to protect the negotiation process in the second phase. The quick mode implements the negotiation of the IPSec security alliance between the two communicating parties and determines the IPSec security policy and session key of the two communicating parties. The exchange process in the first phase consists of 6 messages. The identity authentication of both parties is carried out using digital certificates. The exchange process in the main mode is as follows: Figure 1 shown.

[0004] With the development of quantum computing technology, traditional public key cryptography algorithms (such as RSA and SM2) are at risk of being cracked by quantum computers. Post-quantum cryptography (PQC) has emerged to provide encryption algorithms that are resistant to quantum computing attacks. Existing IPSec VPN security gateways primarily rely on classical cryptographic algorithms such as SM2 for identity authentication and key negotiation, and urgently need to be upgraded to address the threat of quantum computing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an IPSec VPN security gateway communication method integrating post-quantum cryptography technology, which can improve the security of the IPSec VPN security gateway and resist quantum computing attacks.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0007] An IPSec VPN security gateway communication method integrating post-quantum cryptography technology comprises the following steps: S1. In the first phase of IKE key negotiation in main mode, a hybrid SM2 and PQC algorithm and a hybrid PQC digital certificate are used, replacing the traditional single SM2 algorithm and digital certificates based on the SM2 cryptographic algorithm. S2. The initiator and responder use the PQC encryption key pair and PQC signature key pair for key exchange and data signature, respectively, and use the SM2 encryption key pair and SM2 signature key pair for key exchange and data signature; S3. In message 1, the initiator sends a security alliance payload encapsulated in the responder's recommended payload, and the recommended payload is encapsulated in the transform payload, and the SA attribute payload in the transform payload adds a public key algorithm attribute value that integrates SM2 and PQC algorithms; S4. In message 2, the responder sends an SA payload containing the PQC concatenated hybrid signature certificate and encryption certificate, and the SA payload indicates the received SA proposal sent by the initiator; S5. In messages 3 and 4, the initiator and responder complete key exchange and verification. The initiator and responder exchange data, including a one-time random number (nonce) and an identity identifier (ID) payload. The exchanged data is encrypted and protected using the PQC key in the other party's encryption certificate to pair with the negotiated temporary key. The encrypted data is further encrypted and protected using a classic encryption algorithm. Both parties digitally sign the exchanged data.

[0008] Preferably, the PQC algorithm in step S1 includes but is not limited to a key encapsulation algorithm based on a lattice cryptographic mechanism: ML-KEM, and a digital signature algorithm based on a lattice cryptographic mechanism: ML-DSA; the hybrid PQC digital certificate is a standard X.509 format certificate, and uses a new OID to identify the hybrid algorithm; the public key value uses the PQC public key value and the SM2 public key value in series, with the PQC public key value in front and the SM2 public key value in the back; the signature value uses the PQC signature value and the SM2 signature value in series, with the PQC signature value in front and the SM2 signature value in the back.

[0009] Preferably, the public key algorithm attribute value of the fusion of SM2 and PQC algorithms in step S3 is a predefined object identifier OID value ASYMMETRIC_SM2_MLKEM_MLDSA, and ASYMMETRIC_SM2_MLKEM_MLDSA is used to explicitly declare in the SA attribute payload of the IKE key negotiation that the current key negotiation adopts a hybrid algorithm combination based on SM2 and PQC algorithms to replace the traditional single SM2 algorithm, and in the fusion PQC and SM2 key negotiation scenario, both the sender and the responder use ASYMMETRIC_SM2_MLKEM_MLDSA.

[0010] Preferably, the initiator and the responder in S5 complete the key exchange and verification in message 3, including the following steps: A1. First, the initiator uses the responder's PQC encryption key pair public key EncPubKey R The initiator performs PQC key encapsulation encryption on the shared key Ski generated by the initiator to obtain an encrypted ciphertext. The initiator then uses the responder's classic asymmetric public key pub_r to perform classic asymmetric encryption on the encrypted ciphertext to obtain a double-encrypted ciphertext. Finally, the initiator uses the shared key Ski to encrypt the random number Ni generated by the initiator and the initiator's identity IDi using the classic symmetric encryption algorithm, and also attaches its own PQC signature certificate CERT_sig_i and encryption certificate CERT_enc_i to construct the message XCHi. A2. The initiator uses its own PQC signature key to the private key SignPriKey I The signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" is signed using the PQC algorithm. The initiator uses its own classic asymmetric signature private key priv_i to sign the same signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" using the SM2 algorithm, and finally generates a signature value SIGi_b; the Ski_b is a derived value of Ski, Ni_b is a derived value of Ni, IDi_b is a derived value of IDi, and CERT_enc_i_b is a derived value of CERT_enc_i; A3. The responder first uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHi, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Ski, and then uses Ski to decrypt to obtain Ni and IDi; A4. The responder uses the initiator's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGi_b. If the verification succeeds, the correctness of the third message is proved.

[0011] Preferably, the initiator and the responder in S5 complete the key exchange and verification in message 4, including the following steps: B1. First, the responder uses the initiator's PQC encryption key to encrypt the public key EncPubKey I The responder generates a shared key Skr and performs key encapsulation encryption using the PQC algorithm to obtain an encrypted ciphertext. The responder then uses the initiator's classic asymmetric public key pub_i to perform classic asymmetric encryption on the encrypted ciphertext to obtain a double-encrypted ciphertext. Finally, the responder generates a random number Nr and its identity IDr and encrypts them using the shared key Skr using a classic symmetric encryption algorithm to construct a message XCHr. B2. The responder uses its own PQC signature key to private key SignPriKey R The signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" is signed using the PQC algorithm. The responder uses its own classic asymmetric signature private key priv_r to sign the same signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" using the SM2 algorithm, and finally generates a signature value SIGr_b; the Skr_b is a derived value of Skr, Nr_b is a derived value of Nr, IDr_b is a derived value of IDr, and CERT_enc_r_b is a derived value of the PQC encryption certificate CERT_enc_r; B3. The initiator uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHr, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Skr, and then uses Skr to decrypt to obtain Nr and IDr; B4. The initiator uses the responder's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGr_b. If the verification succeeds, the correctness of the fourth message is proved.

[0012] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is as follows.

[0013] The present invention improves the security of IPSec VPN security gateway communication by using the SM2 and PQC hybrid algorithm and the hybrid PQC digital certificate in the IKE key negotiation phase, and can effectively cope with the threats brought by quantum computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram of the exchange process of the first phase of main mode of existing IKE key negotiation; Figure 2 This is an architectural diagram of the IPSec VPN security gateway system that integrates post-quantum cryptography technology using the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] A communication method for an IPSec VPN security gateway that integrates post-quantum cryptography technology. The upgrade and transformation primarily involves the first, second, third, and fourth messages of the first-phase main mode. In the second message, the responder sends a PQC concatenated hybrid signature certificate and encryption certificate. In the third and fourth messages, the key is first protected using a post-quantum cryptographic algorithm, and then the protection result of the post-quantum cryptographic algorithm is protected with a classical key. In the third message, the initiator sends a PQC concatenated hybrid signature certificate and encryption certificate. Other message formats and message processing methods are consistent with GM / T 0022, "IPSecVPN Technical Specification." Specifically, the method includes the following steps: S1. In the first phase of IKE key negotiation in main mode, the SM2 and PQC hybrid algorithm and hybrid PQC digital certificates are used to replace the traditional single SM2 algorithm and digital certificates based on the SM2 cryptographic algorithm.

[0017] The main method is to embed the PQC algorithm in the existing technical specifications and use a hybrid PQC algorithm digital certificate. The PQC algorithm includes but is not limited to the ML-KEM algorithm and the ML-DSA algorithm, wherein the ML-KEM algorithm is a key encapsulation algorithm based on the lattice cryptography mechanism, which is used for the key encapsulation mechanism; the ML-DSA algorithm is a digital signature algorithm based on the lattice cryptography mechanism, which is used for the digital signature; the hybrid PQC digital certificate is a standard X.509 format certificate, and uses a new OID to identify the hybrid algorithm; the public key value uses the PQC public key value and the SM2 public key value in series, with the PQC public key value in front and the SM2 public key value in the back; the signature value uses the PQC signature value and the SM2 signature value in series, with the PQC signature value in front and the SM2 signature value in the back.

[0018] The client (Initiator) and server (Responder) need to have a serial hybrid signature digital certificate, a serial hybrid encryption digital certificate and the corresponding PQC encryption key pair private key, PQC signature key pair private key, SM2 encryption key pair private key, and SM2 signature key pair private key. The client's PQC encryption key pair public key is included in the serial hybrid encryption digital certificate and is recorded as EncPubKey I , the private key of the PQC encryption key pair is recorded as EncPriKey I The client's PQC signature key pair public key is included in the serial hybrid signature digital certificate, recorded as SignPubKey I , the private key of the PQC signature key pair is recorded as SignPriKey I The server's PQC encryption key pair public key is included in the serial hybrid encryption digital certificate, recorded as EncPubKey R , the private key of the PQC encryption key pair is recorded as EncPriKeyR The server's PQC signature key pair public key is included in the serial hybrid signature digital certificate, recorded as SignPubKey R , the private key of the PQC signature key pair is recorded as SignPriKey R .

[0019] S2. The initiator and responder use the PQC encryption key pair and PQC signature key pair for key exchange and data signature respectively, and use the SM2 encryption key pair and SM2 signature key pair for key exchange and data signature at the same time.

[0020] S3. In message 1, the initiator sends a security association payload encapsulating a proposal payload to the responder, and the proposal payload encapsulates a transformation payload. The SA attribute payload in the transformation payload is newly added with a public key algorithm attribute value that integrates the SM2 and PQC algorithms.

[0021] Specifically, the initiator sends a security association payload encapsulated with a suggestion payload to the responder, and the suggestion payload is encapsulated with a transformation payload. The SA attribute payload in the transformation payload needs to add a public key algorithm attribute value, as shown in the following table. name describe value ASYMMETRIC_RSA RSA public key cryptography algorithm 1 ASYMMETRIC_SM2 SM2 elliptic curve cryptography algorithm 2 ASYMMETRIC_SM2_MLKEM_MLDSA Fusion of SM2 and PQC algorithms 3 The public key algorithm attribute value of the integrated SM2 and PQC algorithms is the predefined object identifier OID value ASYMMETRIC_SM2_MLKEM_MLDSA. ASYMMETRIC_SM2_MLKEM_MLDSA is used to explicitly declare in the SA attribute payload of IKE key negotiation that the current key negotiation adopts a hybrid algorithm based on the SM2 and PQC algorithms, replacing the traditional single SM2 algorithm. In the PQC and SM2 integrated key negotiation scenario, both the sender and the responder use ASYMMETRIC_SM2_MLKEM_MLDSA.

[0022] S4. In message 2, the responder sends an SA payload containing the PQC concatenated hybrid signature certificate and encryption certificate, and the SA payload indicates the received SA proposal sent by the initiator.

[0023] Specifically, the responder sends an SA payload and the responder's PQC concatenated hybrid signature certificate and encryption certificate, and the payload indicates the SA proposal sent by the initiator that it receives.

[0024] S5. In messages 3 and 4, the initiator and responder complete key exchange and verification. The initiator and responder exchange data, including a one-time random number (nonce) and an identity identifier (ID) payload. The exchanged data is encrypted and protected using the PQC key in the other party's encryption certificate to pair with the negotiated temporary key (Sk). The encrypted data is further encrypted using a classic encryption algorithm. Both parties digitally sign the exchanged data.

[0025] The one-time random number nonce is a parameter required to generate encryption keys and authentication keys; the identity ID is the identifier of the initiator or responder; the temporary key Sk includes the shared key Ski generated by the initiator and the shared key Skr generated by the responder.

[0026] Specifically, the exchange data of the initiator is as follows: XCHi=Asymmetric_Encrypt(PQC_PubKey_Enc(Ski, EncPubKey R ),pub_r)| Symmetric_Encrypt(Ni,Ski)|Symmetric_Encrypt(IDi,Ski)|CERT_sig_i|CERT_enc_i; SIGi_b=Asymmetric_Sign(Ski_b|Ni_b|IDi_b|CERT_enc_i_b,priv_i)|PQC_SecKey_Sign(Ski_b|Ni_b|IDi_b|CERT_enc_i_b, SignPriKey I ); Among them, Asymmetric_Encrypt represents the classic asymmetric algorithm encryption, the first parameter of this method PQC_PubKey_Enc(Ski, EncPubKey R ) represents the encrypted object, and the second parameter pub_r represents the classic public key data of the responder; Asymmetric_Sign represents the classic asymmetric signature algorithm. The first parameter of this method, Ski_b|Ni_b|IDi_b|CERT_enc_i_b,priv_i)|PQC_SecKey_Sign(Ski_b|Ni_b|IDi_b|CERT_enc_i_b), represents the data to be signed, where Ski_b is the derived value of Ski, Ni_b is the derived value of Ni, IDi_b is the derived value of IDi, and CERT_enc_i_b is the derived value of CERT_enc_i, and Ski_b, Ni_b, IDi_b and CERT_enc_i_b are all in binary form. The second parameter represents SignPriKey IThe initiator's private key data; PQC_PubKey_Enc represents the key encryption method based on PQC public key encryption. The first parameter Ski of this method represents the shared key generated by this method. The second parameter represents the encrypted public key of the responder's post-quantum algorithm. The return value of this method is the encrypted ciphertext sent to the responder. PQC_SecKey_Sign represents the PQC private key signature method. The first parameter Ski_b|Ni_b|IDi_b|CERT_enc_i_b of this method represents the data to be signed. The second parameter SignPriKey I Represents the signature private key of the initiator's post-quantum algorithm; | represents binary data connection; Symmetric_Encrypt represents the classical symmetric encryption method. The first parameter Ni of this method is the random number generated by the initiator, IDi is the initiator's identity, representing the plaintext data, and the second parameter Ski is the shared key generated by the initiator, representing the encryption key; CERT_sig_i is the PQC signature certificate, and CERT_enc_i is the PQC encryption certificate.

[0027] Specifically in the signature operation process, it is necessary to perform a summary operation on the signature data. Then the input data of the post-quantum cryptographic signature algorithm can use the summary operation result in the classical cryptographic signature algorithm process, which can reduce the number of summary operations and improve the operation efficiency.

[0028] When the responder receives the above message, it first uses the private key of the classical public key cryptography algorithm to decrypt XCHi, then uses the private key of the post-quantum cryptography algorithm to decrypt to obtain Ski, and then uses Ski to decrypt to obtain Ni and IDi; secondly, the data signature is verified using the classical public key cryptography algorithm and the post-quantum signature algorithm. If the verification is successful, the correctness of the third message is proved. At this time, the initiator and the responder have obtained the first shared key Ski.

[0029] Specifically, the initiator and responder complete key exchange and verification in message 3, including the following steps: A1. First, the initiator uses the responder's PQC encryption key pair public key EncPubKey R The shared key Ski generated by the initiator is encrypted using the PQC algorithm key encapsulation to obtain an encrypted ciphertext; then, the initiator uses the responder's classic asymmetric public key pub_r to perform classic asymmetric encryption on the encrypted ciphertext to obtain a double-encrypted ciphertext; finally, the shared key Ski is used to encrypt the random number Ni generated by the initiator and the initiator's identity IDi through the classic symmetric encryption algorithm, and at the same time attach its own PQC signature certificate CERT_sig_i and encryption certificate CERT_enc_i to construct the message XCHi.

[0030] A2. The initiator uses its own PQC signature key to the private key SignPriKey I The same signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" is signed using the PQC algorithm. The initiator uses its own classic asymmetric signature private key priv_i to sign the signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" using the SM2 algorithm, and finally generates the signature value SIGi_b.

[0031] A3. The responder first uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHi, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Ski, and then uses Ski to decrypt to obtain Ni and IDi.

[0032] A4. The responder uses the initiator's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGi_b. If the verification succeeds, the correctness of the third message is proved.

[0033] Specifically, the data exchanged by the responder is as follows: XCHr=Asymmetric_Encrypt(PQC_PubKey_Enc(Skr, EncPubKey I ),pub_i)| Symmetric_Encrypt(Nr,Skr)|Symmetric_Encrypt(IDr,Skr)|; SIGi_b=Asymmetric_Sign(Skr_b|Nr_b|IDr_b|CERT_enc_r_b,priv_r)|PQC_SecKey_Sign(Skr_b|Nr_b|IDr_b|CERT_enc_r_b, SignPriKey R ).

[0034] Among them, Asymmetric_Encrypt represents the classic asymmetric algorithm encryption, the first parameter of this method is PQC_PubKey_Enc(Skr, EncPubKey I) represents the encrypted object, and the second parameter pub_i represents the classic public key data of the initiator; Asymmetric_Sign represents the classic asymmetric signature algorithm. The first parameter of this method (Skr_b|Nr_b|IDr_b|CERT_enc_r_b,priv_r)|PQC_SecKey_Sign(Skr_b|Nr_b|IDr_b|CERT_enc_r_b) represents the data to be signed, where Skr_b is the derived value of Skr, Nr_b is the derived value of Nr, IDr_b is the derived value of IDr, CERT_enc_r_b is the derived value of CERT_enc_r, and Skr_b, Nr_b, IDr_b, CERT_enc_r_b and CERT_enc_r are all in binary form. The second parameter SignPriKey R Represents the initiator's private key data; PQC_PubKey_Enc represents the key encryption method based on PQC public key encryption. The first parameter Skr of this method represents the shared key generated by this method, and the second parameter EncPubKey I Represents the post-quantum encryption public key of the initiator. The return value of this method is the encrypted ciphertext sent to the initiator. PQC_SecKey_Sign represents the PQC private key signature method. The first parameter Skr_b|Nr_b|IDr_b|CERT_enc_r_b of this method represents the data to be signed. The second parameter SignPriKey R The symmetric_encrypt parameter represents the responder's post-quantum signature private key; | represents a binary data connection; Symmetric_Encrypt represents the classical symmetric encryption method, where the first parameter Nr is a random number generated by the responder, IDr is the responder's identity, and represents the plaintext data. The second parameter Skr represents the encryption key. Specifically, during the signature operation, a digest operation must be performed on the data being signed. The post-quantum cryptographic signature algorithm can use the digest operation result from the classical cryptographic signature algorithm as input data, reducing the number of digest operations and improving efficiency.

[0035] When the initiator receives the above message, it first decrypts XCHr using the private key of the classical public key cryptography algorithm, then uses the private key of the post-quantum cryptography algorithm to decrypt to obtain Skr, and then uses Skr to decrypt to obtain Nr and IDr; secondly, the data signature is verified using the classical public key cryptography algorithm and the post-quantum signature algorithm. If the verification is successful, the correctness of the fourth message is proved. At this time, the initiator and the responder have obtained the first shared key Ski and the second shared key Skr.

[0036] Specifically, the initiator and responder complete key exchange and verification in message 4, including the following steps: B1. First, the responder uses the initiator's PQC encryption key to encrypt the public key EncPubKey I The responder generates a shared key Skr and performs key encapsulation encryption using the PQC algorithm to obtain an encrypted ciphertext. The responder then uses the initiator's classic asymmetric public key pub_i to perform classic asymmetric encryption on the encrypted ciphertext to obtain a double-encrypted ciphertext. Finally, the responder generates a random number Nr and its identity IDr and encrypts them using the shared key Skr using a classic symmetric encryption algorithm to construct a message XCHr. B2. The responder uses its own PQC signature key to private key SignPriKey R The signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" is signed using the PQC algorithm. The responder uses its own classic asymmetric signature private key priv_r to sign the same signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" using the SM2 algorithm to generate the signature value SIGr_b.

[0037] B3. The initiator uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHr, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Skr, and then uses Skr to decrypt to obtain Nr and IDr; B4. The initiator uses the responder's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGr_b. If the verification succeeds, the correctness of the fourth message is proved.

[0038] It should be noted that if the other party's certificate is already in the revocation list, the system should send an INVALID_CERTIFICATE notification message. After the exchange of messages 3 and 4 is completed, the two parties involved in the communication have generated basic key parameters.

[0039] S6. Messages 5 and 6 are executed in accordance with the requirements of the standard specifications.

[0040] An IPSec VPN security gateway system integrating post-quantum cryptography technology is implemented based on an IPSec VPN security gateway communication method integrating post-quantum cryptography technology. It is an upgrade and transformation based on the existing standard IPSec VPN security gateway. It mainly uses the PQC algorithm and PQC digital certificate in the main mode of the first phase of IKE key negotiation, combined with Figure 2As shown, it includes components such as a post-quantum cryptography module, a classical cryptography module, an IKE key negotiation module, an IPSec ESP processing module, and a device management service. Among them, the output end of the post-quantum cryptography module is connected to the input end of the IKE key negotiation module and the device management service respectively; the output end of the IKE key negotiation module is connected to the input end of the IPSec ESP processing module; the output end of the classical cryptography module is connected to the input end of the IKE key negotiation module, the IPSec ESP processing module, and the device management service respectively.

[0041] The post-quantum cryptography module is mainly used to implement post-quantum cryptographic algorithms, post-quantum key storage and use.

[0042] The classic cryptographic module is mainly used for classic static key management, classic cryptographic algorithm logic implementation and other functions.

[0043] The device management service is a human-computer interaction module used to manage the parameters, function enablement, and permission roles of the IPSec VPN security gateway.

[0044] The IKE key negotiation module is primarily responsible for securely negotiating and establishing security associations between communicating parties, including key exchange, identity authentication, algorithm negotiation, and message protection, ensuring the initial security of communications.

[0045] The IPSec ESP processing module is responsible for encrypting and authenticating the data actually transmitted, ensuring the confidentiality, integrity, and authenticity of the data during transmission and guaranteeing the continuous security of communications.

Claims

1. An IPSec VPN security gateway communication method integrating post-quantum cryptography technology, characterized by: The following steps are involved: S1. In the first phase of IKE key negotiation in main mode, a hybrid SM2 and PQC algorithm and a hybrid PQC digital certificate are used, replacing the traditional single SM2 algorithm and digital certificates based on the SM2 cryptographic algorithm. S2. The initiator and responder use the PQC encryption key pair and PQC signature key pair for key exchange and data signature, respectively, and use the SM2 encryption key pair and SM2 signature key pair for key exchange and data signature; S3. In message 1, the initiator sends a security alliance payload encapsulated in the responder's recommended payload, and the recommended payload is encapsulated in the transform payload, and the SA attribute payload in the transform payload adds a public key algorithm attribute value that integrates SM2 and PQC algorithms; S4. In message 2, the responder sends an SA payload containing the PQC concatenated hybrid signature certificate and encryption certificate, and the SA payload indicates the received SA proposal sent by the initiator; S5. In messages 3 and 4, the initiator and responder complete key exchange and verification. The initiator and responder exchange data, including a one-time random number (nonce) and an identity identifier (ID) payload. The exchanged data is encrypted and protected using the PQC key in the other party's encryption certificate to pair with the negotiated temporary key. The encrypted data is further encrypted and protected using a classic encryption algorithm. Both parties digitally sign the exchanged data.

2. The IPSec VPN security gateway communication method integrating post-quantum cryptography technology according to claim 1 is characterized in that: In step S1, the PQC algorithm includes but is not limited to a key encapsulation algorithm based on a lattice cryptographic mechanism: ML-KEM, and a digital signature algorithm based on a lattice cryptographic mechanism: ML-DSA; the hybrid PQC digital certificate is a standard X.509 format certificate, and uses a new OID to identify the hybrid algorithm; the public key value uses the PQC public key value and the SM2 public key value in series, with the PQC public key value in front and the SM2 public key value in the back; the signature value uses the PQC signature value and the SM2 signature value in series, with the PQC signature value in front and the SM2 signature value in the back.

3. The IPSec VPN security gateway communication method integrating post-quantum cryptography technology according to claim 2 is characterized in that: In step S3, the public key algorithm attribute value of the fusion of SM2 and PQC algorithms is a predefined object identifier OID value ASYMMETRIC_SM2_MLKEM_MLDSA. ASYMMETRIC_SM2_MLKEM_MLDSA is used to explicitly declare in the SA attribute payload of the IKE key negotiation that the current key negotiation adopts a hybrid algorithm combination based on the SM2 and PQC algorithms to replace the traditional single SM2 algorithm. In the fusion PQC and SM2 key negotiation scenario, both the sender and the responder use ASYMMETRIC_SM2_MLKEM_MLDSA.

4. The IPSec VPN security gateway communication method integrating post-quantum cryptography technology according to claim 2 is characterized in that: In S5, the initiator and the responder complete the key exchange and verification in message 3, including the following steps: A1. First, the initiator uses the responder's PQC encryption key pair public key EncPubKeyR to perform PQC algorithm key encapsulation encryption on the shared key Ski generated by the initiator, obtaining an encrypted ciphertext. Then, the initiator uses the responder's classical asymmetric public key pub_r to perform classical asymmetric encryption on the encrypted ciphertext, obtaining a double-encrypted ciphertext. Finally, the initiator uses the shared key Ski to encrypt the random number Ni generated by the initiator and the initiator's identity IDi using the classical symmetric encryption algorithm, along with its own PQC signature certificate CERT_sig_i and encryption certificate CERT_enc_i, to construct the message XCHi. A2. The initiator uses its own PQC signature key pair private key SignPriKeyI to sign the signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" using the PQC algorithm. The initiator uses its own classic asymmetric signature private key priv_i to sign the same signature data "Ski_b|Ni_b|IDi_b|CERT_enc_i_b" using the SM2 algorithm, and finally generates the signature value SIGi_b; the Ski_b is the derived value of Ski, Ni_b is the derived value of Ni, IDi_b is the derived value of IDi, and CERT_enc_i_b is the derived value of CERT_enc_i; A3. The responder first uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHi, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Ski, and then uses Ski to decrypt to obtain Ni and IDi; A4. The responder uses the initiator's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGi_b. If the verification succeeds, the correctness of the third message is proved.

5. The IPSec VPN security gateway communication method integrating post-quantum cryptography technology according to claim 4 is characterized in that: In S5, the initiator and the responder complete the key exchange and verification in message 4, including the following steps: B1. First, the responder uses the initiator's PQC encryption key to perform PQC key encapsulation encryption on the responder's shared key Skr using the public key EncPubKeyI, resulting in encrypted ciphertext. Then, the responder uses the initiator's classical asymmetric public key pub_i to perform classical asymmetric encryption on the encrypted ciphertext, resulting in a double-encrypted ciphertext. Finally, the responder uses the shared key Skr to encrypt the responder's generated random number Nr and the responder's identity IDr using the classical symmetric encryption algorithm, constructing the message XCHr. B2. The responder uses its own PQC signature key pair private key SignPriKeyR to sign the signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" using the PQC algorithm. The responder uses its own classic asymmetric signature private key priv_r to sign the same signature data "Skr_b|Nr_b|IDr_b|CERT_enc_r_b" using the SM2 algorithm, ultimately generating a signature value SIGr_b; the Skr_b is a derived value of Skr, Nr_b is a derived value of Nr, IDr_b is a derived value of IDr, and CERT_enc_r_b is a derived value of the PQC encryption certificate CERT_enc_r; B3. The initiator uses its own private key of the classical public key cryptography algorithm to perform classical asymmetric decryption on XCHr, then uses its own private key of the post-quantum cryptography algorithm to perform PQC decryption to obtain Skr, and then uses Skr to decrypt to obtain Nr and IDr; B4. The initiator uses the responder's classical public key cryptography algorithm and post-quantum signature algorithm to verify SIGr_b. If the verification succeeds, the correctness of the fourth message is proved.

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