Quantum key fused block encryption method, communication system and evaluation method thereof

Abstract

The invention discloses a quantum key fused block encryption method, a communication system and an evaluation method thereof, and the method comprises the steps: fusing a quantum key generated by quantum key division into an Internet key exchange protocol of IPsec to form a mixed key; the sender and the receiver carry out message transmission through the mixed key, the authentication head and the packaging security load, so that the quantum key is integrated into the IPsec framework; and meanwhile, different quantum keys are used in each VPN channel, so that one-time pad is realized. In addition, the invention further provides a method for evaluating the performances such as the key consumption rate, the maximum supportable VPN tunnel number and the total throughput. According to the invention, the security and stability of data transmission in the quantum computer era can be improved.

Description

Technical Field

[0001] The present invention relates to the field of quantum information and network information security, and in particular to a block encryption method, a communication system and an evaluation method thereof integrating quantum keys. Background Art

[0002] In modern communication systems, the Internet Protocol Security (IPsec) serves as a set of protocols and services that protect IP networks. It operates at the network layer of the Open Systems Interconnect (OSI) model. Its key components include the Internet Key Exchange (IKE), the Authentication Header (AH), and the Encapsulating Security Payload (ESP). These components work together to ensure the confidentiality, integrity, source authentication, and resistance to replay attacks of data transmission. IPsec is widely used to secure internal communications within enterprises and organizations, and as a virtual private network (VPN) technology. The IKE protocol, as the core component of IPsec, establishes a secure connection through the negotiation of a block encryption algorithm. However, the algorithms used in this process are extremely vulnerable to the threat of quantum computing.

[0003] To address the potential threats posed by quantum computing, researchers have proposed quantum key distribution (QKD), which leverages the fundamental principles of quantum mechanics to ensure theoretical security. QKD allows communicating parties to establish a symmetric key and, through a one-time password (OTP) technique, ensures unconditional security of information transmission. In 1984, Bennett and Brassard proposed the first QKD protocol, the BB84 protocol. Since then, numerous theoretical schemes and experimental implementations of various QKD protocols have been reported. In recent years, theoretical advances in quantum networks based on QKD protocols have also attracted widespread attention, particularly in the integration of QKD with existing network security protocols. However, integrating QKD with IPsec requires modifications and optimizations to existing network protocols, particularly in key management and distribution. While existing integration schemes have combined QKD-generated quantum keys with the block cipher algorithms of IPsec's key management mechanisms (such as the IKE protocol), the integration process is complex and difficult to evaluate the performance of the resulting communication system. Summary of the Invention

[0004] Purpose of the invention: The first purpose of the present invention is to provide a block encryption implementation method and communication system that integrates quantum keys, solves the complex problems of the integration process, and provides new ideas for the implementation method of block encryption communication; the second purpose of the present invention is to provide an evaluation method for the communication system, which can accurately evaluate the system's key consumption rate, the maximum number of VPN tunnels that can be supported, and the total throughput.

[0005] Technical Solution: The present invention provides a method for implementing quantum key-integrated block encryption. The sender and receiver of an IPsec system use a hybrid key, an authentication header, and an encapsulating security payload to transmit messages. The hybrid key generation method includes the following steps:

[0006] Step 1: The sender and receiver generate a key SKEYID d 、SKEYID a and SKEYID e And generate corresponding quantum keys QKD keys for each VPN channel;

[0007] Step 2: Divide the quantum key QKD keys into four segments of the same length to obtain QKD d , QKD a , QKD e and QKD s , change SKEYID d 、SKEYID a and SKEYID e Respectively with QKD d , QKD a and QKD e Use the extended pseudo-random function to fuse and get the new key QSKEYID d 、QSKEYID a and QSKEYID e ; The extended pseudo-random function is to call the pseudo-random function multiple times and concatenate the results of the pseudo-random function so that the generated key reaches the target length;

[0008] Step 3: Use QSKEYID d Generate key material KEYMAT;

[0009] Step 4: Combine KEYMAT with QKD s The mixed key is obtained by using the extended pseudo-random function fusion.

[0010] Furthermore, in step 1, the sender and the receiver use a pseudo-random function to generate a seed key, and generate a key SKEYID based on the seed key. d 、SKEYID a and SKEYID e.

[0011] Furthermore, in step 2, the new key QSKEYID is determined according to the number of bits of the seed key. d 、QSKEYID a and QSKEYID e length.

[0012] Furthermore, in step 2, the workflow of the extended pseudo-random function is as follows: assuming that any keys K and S are fused using the extended pseudo-random function, prf+(K,S)=T1|T2|T3|T4…, where:

[0013] T1=prf(K,S|0x01);

[0014] T2 = prf(K, T1|S|0x02);

[0015] T3 = prf(K, T2|S|0x03);

[0016] T4=prf(K,T3|S|0x04);

[0017] prf is a pseudorandom function.

[0018] Furthermore, the key material KEYMAT in step 3 = prf(QSKEYID d ,protocol|SPI|Ni|Nr), where protocol is the protocol number of the Authentication Header (AH) and Encapsulating Security Payload (ESP) in the IPsec protocol, which are 51 and 50 respectively. SPI is a 32-bit unique identifier used to distinguish different security associations. Its value is assigned by the receiver when establishing a security association. Ni and Nr are random numbers.

[0019] The communication system described in the present invention uses the block encryption implementation method integrating quantum keys to transmit messages.

[0020] The electronic device described in the present invention includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the computer program is loaded into the processor, it implements the block encryption method for integrating quantum keys.

[0021] The computer-readable storage medium of the present invention stores a computer program, which, when executed by a processor, implements the method for implementing block encryption using a fused quantum key.

[0022] The communication system evaluation method of the present invention includes calculating the key consumption rate Calculate the number of supported VPN tunnels where R Qis the key rate of quantum key QKD keys, t is the key SKEYID d 、SKEYID a or SKEYID e length.

[0023] Furthermore, it also includes calculating the total throughput Thpt=n VPN R VPN , where R VPN The maximum data transmission rate achievable through a single VPN tunnel.

[0024] Beneficial effects: Compared with the prior art, the advantages of the present invention are: (1) In the Internet Key Exchange Protocol of the IPsec protocol, the present invention fuses the key generated by the block encryption algorithm and the quantum key generated by the quantum key distribution protocol into a new key for application in the entire IPsec system. The fusion process is simple and practical, providing a new solution for the fusion method of classical cryptography and quantum cryptography; (2) The present invention uses different quantum keys for different virtual private network (VPN) channels to achieve one-time one-key; (3) The present invention designs a performance evaluation method for communication systems using hybrid keys, including the system's key consumption rate, the maximum number of VPN tunnels that can be supported, and the total throughput. After simulation evaluation, the present invention can efficiently and securely transmit data in the era of quantum computers, providing a direction for the design and implementation of future quantum secure communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the packet encryption implementation method of the present invention.

[0026] Figure 2 Graph showing the relationship between key consumption rate and transmission distance in an embodiment of the present invention.

[0027] Figure 3 This is a relationship diagram between the maximum number of VPN tunnels supported by the system and the transmission distance in an embodiment of the present invention.

[0028] Figure 4 1 is a diagram showing the relationship between the total system throughput and the transmission distance in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In this invention, both communicating parties in the IPsec protocol not only generate classical keys using pseudorandom functions but also employ a quantum key distribution protocol to generate quantum keys. This quantum key is then fused with the key generated by the block encryption algorithm during the security association phase of the Internet Key Exchange protocol to produce a new key. This new key is then fused with the key generated by the quantum key distribution protocol through block encryption, using the key generated during the IPsec security association phase, to produce the final key. The sender and receiver use the final key to encrypt IP packets, adding an authentication header and the Encapsulating Security Payload protocol for transmission. This integrates the quantum key generated by the quantum key distribution protocol into the IPsec framework, and uses a different quantum key for each virtual private network (VPN) channel, achieving a one-time pad. Furthermore, the invention proposes methods for evaluating system performance, such as the key consumption rate, the maximum number of VPN tunnels supported, and the total throughput. This invention provides sufficient key consumption for IPsec block encryption, improving the security and stability of data transmission in the era of quantum computers.

[0030] like Figure 1 As shown, the block encryption method integrating quantum key includes the following steps.

[0031] Step (1): The sender and receiver use the BB84 quantum key distribution protocol. The sender sends a quantum state sequence with a total number of pulses N to the receiver through the quantum channel. The receiver randomly selects basis vectors to measure these states. After post-processing steps such as error correction and privacy amplification, the two communicating parties generate R Q The quantum keys (QKD keys) of bits are stored in the key pool.

[0032] Step (2) involves two phases in the Internet Key Exchange (IKE) module of the IPsec protocol: the IKE (Internet Key Exchange Security Association) phase and the IPsec (IPsec) Security Association (IPsec) phase. The SA includes the security protocol used by the two parties in the negotiation, the data transmission encapsulation method, the encryption and authentication algorithms, and the key for data transmission. This invention primarily focuses on key-related aspects and does not involve other message exchanges during the negotiation process.

[0033] The first phase of IKEv1 is to establish an IKE SA. After the sender and receiver complete a series of related message exchanges, they first use a pseudo-random function to generate a seed key SKEYID:

[0034] SKEYID=prf(Hash(Ni|Nr),CKYi|CKYr) (1)

[0035] Here, Hash represents a hash function; Ni and Nr represent random numbers shared between the sender and receiver during message exchange; Ni|Nr represents the concatenation of Ni and Nr; and CKYi and CKYr represent the cached files browsed by the sender and receiver's websites. prf(K, S) represents a pseudorandom function. This example uses the AES-XCBC-PRF-128 function, which is a pseudorandom function based on the AES algorithm. In this function, assuming K is a 128-bit key and S represents a message of arbitrary length, the function output t is the 128-bit key.

[0036] The process of generating seed keys using a pseudo-random function is as follows:

[0037] Generate three keys (K1, K2, K3) using AES encryption:

[0038]

[0039] Among them, Const1, Const2, and Const3 are fixed constants.

[0040] The message S is divided into 128-bit blocks: S = S1, S2, ..., S n , each block is 128 bits. If the last block S n If it is less than 128 bits, fill it with 0 to make it 128 bits. 128 (128-bit all-zero vector), the block message S i Do the following:

[0041]

[0042] Where i = 1, 2, ..., n-1. Finally, process the last block based on the length of S:

[0043]

[0044] If S n If S is a 128-bit block, use formula (4). n If the block size is smaller than 128 bits, use formula (5). n It is the output of the function prf, namely the seed key SKEYID.

[0045] Step (3), the seed key SKEYID is used to generate the key SKEYID d 、SKEYID a and SKEYID e :

[0046] SKEYID d=prf(SKEYID,CKYi|CKYr|0) (6)

[0047] SKEYID a =prf(SKEYID,SKEYID d |CKYi|CKYr|1) (7)

[0048] SKEYID e =prf(SKEYID,SKEYID a |CKYi|CKYr|2) (8)

[0049] Where the values ​​0, 1, and 2 in the formula are represented by a single octet; SKEYID d Used to generate session keys in child security associations; SKEYID a SKEYID is a working key used to authenticate the integrity of messages and the identity of the data source. e A working key used to protect the confidentiality of messages.

[0050] Step (4), randomly divide the QKD keys into four segments: QKD d , QKD a , QKD e and QKD s , the length of each segment is Then generate the key SKEYID d 、SKEYID a and SKEYID e Respectively with QKD d , QKD a and QKD e Fusion to get the key:

[0051] QSKEYID d =prf+(QKD d ,SKEYID d ) (9)

[0052] QSKEYID a =prf+(QKD a ,SKEYID a ) (10)

[0053] QSKEYID e =prf+(QKD e ,SKEYID e ) (11)

[0054] The number of bits of each quantum key required for fusion is determined by the number of bits of the seed key. prf+ represents an extended pseudo-random function, which calls the prf function multiple times and concatenates the results of each call to generate a key of the desired length. Its workflow is expressed as follows:

[0055]

[0056] QSKEYID d 、QSKEYID a and QSKEYID e It is generated based on OKD keys, where QSKEYID d Replaces SKEYID in the IPsec protocol d , used to generate session keys, and similarly, QSKEYID a Alternative SKEYID a As the authentication key, QSKEYID e Alternative SKEYID e As encryption key.

[0057] Step (5) Enter the second phase of IKEv1 and establish IPsec SA. Use QSKEYID d Obtain the key material KEYMAT required in the IPsec protocol:

[0058] KEYMAT=prf(QSKEYID d ,protocol|SPI|Ni|Nr) (13)

[0059] The protocol and SPI are selected from the suggested payload of the IKE SA. Since the number of bits output by the prf function does not meet the KEYMAT key length requirement, it is necessary to use the feedback and connection methods to extend it, as follows:

[0060]

[0061] Step (6) Combine KEYMAT with QKD s Fusion gives QKEYMAT:

[0062] QKEYMAT=prf+(QKD s ,KEYMAT) (15)

[0063] Step (7) The sender and receiver use the final key QKEYMAT to encrypt the IP packet and add the authentication header and Encapsulating Security Payload protocol for transmission. Therefore, QKD keys are integrated into the packet encryption algorithm of the entire IPsec framework.

[0064] In the communication system using the above method for transmission, in the process of generating QKDkeys using the BB84 quantum key distribution protocol, due to the practical limitations of generating an ideal single-photon source, experiments usually use an approximate light source, such as a weak coherent state light source, so the single-photon probability of the signal state (μ) is for:

[0065]

[0066] Total gain of different states in different bases and total bit error rate for:

[0067]

[0068] Where ξ represents the signal state (μ) or the decoy state (ν); W represents the X-based or Z-based; Y i represents the transmittance of the i-photon state; e i represents the bit error rate of photon state i.

[0069] However, the presence of multiphoton components introduces vulnerability to photon number splitting attacks. To counter such attacks, decoy state techniques are considered, which allow for more accurate estimation of single-photon transmittance in different bases. and single-photon bit error rate The result is:

[0070]

[0071] Where Y0 represents the dark count rate and e0 represents the intrinsic bit error.

[0072] The final formula for the key generation rate per second is:

[0073]

[0074] Where N is the total number of pulses, q is the probability that Alice selects a signal state and prepares it in the Z basis, and Bob also measures it using the Z basis. f is the error correction efficiency; and H2(x) is the binary Shannon entropy function.

[0075] In the IPsec protocol, the key consumption rate refers to the speed at which an IPsec VPN tunnel generates or updates encryption keys per unit time, and is usually related to the establishment and update of security associations. The maximum number of VPN tunnels supported refers to the maximum number of IPsec VPN tunnels that the system can support simultaneously, which depends on the hardware resources and software optimization of the device. The throughput refers to the maximum rate at which IPsec VPN tunnels can transmit data, reflecting the actual data transmission capacity of the system.

[0076] In this embodiment, the key refresh time is set to 1 second, and the AES algorithm generates a seed key of t = 128 bits. The quantum key is consumed 4 times in the entire fusion process, and the amount of quantum key consumed is 4t bits. The final key consumption rate KCR is as follows:

[0077]

[0078] Among them, R Q Indicates the key rate of quantum keys generated per second.

[0079] In the actual experimental communication system, there are multiple VPN tunnels communicating at the same time, and each channel uses a different quantum key for encryption to achieve a one-time pad. Q The number of VPN tunnels that can be supported by a bit quantum key is

[0080]

[0081] In the actual experimental communication system, the maximum data transmission rate that can be achieved by a single VPN tunnel is R VPN =8.31Gbps / VPN. Here, the total throughput of the system Thpt is:

[0082] Thpt=n VPN R VPN . (25)

[0083] The method of the present invention is verified by a specific simulation experiment below.

[0084] In this experiment, the BB84 quantum key distribution protocol was used to perform numerical simulations on the key consumption rate, the maximum number of VPN tunnels that can be supported, and the total throughput. Table 1 lists the system parameters used in the present invention: d The detector efficiency is y0, the dark count rate is Y0, the error correction efficiency is f, α is the fiber loss coefficient, e0 is the intrinsic bit error, N is the total number of pulses, ∈ is the failure probability, and F is the system clock frequency. The simulation process takes into account finite length effects and global optimization to achieve more realistic results.

[0085] Table I

[0086] <![CDATA[η d ]]> <![CDATA[Y0]]> f α <![CDATA[e0]]> N ∈ F 50％ <![CDATA[1*10 -8 ]]> 1.16 0.2dB / km 0.02 <![CDATA[1*10 13 ]]> <![CDATA[1*10 -10 ]]> <![CDATA[10 9 Hz]]>

[0087] Table II highlights the system key consumption rate KCR and the maximum number of supported VPN tunnels n obtained by evaluating the key rate generated by the BB84 quantum key distribution protocol at a transmission distance of 200 km. VPNand the total throughput Thpt. To demonstrate the performance of the present invention, the key refresh time was set to 1 second. These parameters are essential for evaluating the practical performance of secure communication systems based on quantum key distribution. The throughput value obtained from the actual experimental communication system was 8.31 Gbps / VPN tunnel, reflecting the maximum achievable transmission rate. At the same time, the present invention ensures security based on the key rate constraints of the BB84 protocol.

[0088] Table II

[0089] distance <![CDATA[R Q ]]> KCR <![CDATA[n VPN ]]> Thpt 200km 1772 bits 28.9％ 3 24.93Gbps

[0090] The throughput value is 8.31 Gbps / VPN tunnel, reflecting the maximum achievable transmission rate. At the same time, the present invention ensures security based on the key rate constraint of the BB84 protocol.

[0091] Figure 2 The relationship between key consumption rate and transmission distance is shown. To demonstrate the performance of the present invention, the key refresh time is set to 1 second. The inset diagram provides a detailed view of the key consumption rate variation from 0 to 125 kilometers. As can be seen from the figure, the present invention maintains key consumption below 1% at shorter distances, allowing the deployment of multiple VPN tunnels to increase throughput and shorten key refresh intervals, thereby improving security based on hardware limitations. However, above 250 km, the key generation rate of the BB84 quantum key distribution protocol can no longer support the key consumption required for even a single VPN channel.

[0092] Figure 3 The relationship between the maximum number of VPN tunnels that the system can support and the transmission distance is shown. In order to demonstrate the performance of the present invention, the key refresh interval is set to 1 second. The inset diagram provides a detailed view of the change in VPN tunnels from 150 kilometers to 200 kilometers. It can be seen from the figure that: as the transmission distance increases, the maximum number of VPN tunnels that the BB84 quantum key distribution protocol can support decreases significantly, and the decrease is even greater above 125km. Overall, the BB84 protocol can provide high tunnel support at shorter distances, but cannot support long-distance VPN tunnels, but increasing the key refresh interval can achieve VPN tunnel support. Therefore, at longer distances, it becomes critical to optimize the number of VPN tunnels and the key refresh interval, thereby striking a balance between throughput and key management to maximize system performance.

[0093] Figure 4The figure shows the relationship between total system throughput and transmission distance. The inset provides a detailed view of total throughput from 125 km to 225 km. The figure shows that as transmission distance increases, the total system throughput gradually decreases, with a particularly sharp drop before 50 km. This is because total system throughput is related to the number of VPN tunnels. Furthermore, after 225 km, the keys generated by the BB84 protocol are insufficient to support VPN tunnels, and the total throughput drops to zero. Overall, the BB84 protocol can achieve high throughput over shorter distances, but cannot support long-distance data transmission.

[0094] In summary, the simulation results prove that the present invention can efficiently and securely transmit data in the era of quantum computers, providing direction for the design and implementation of future quantum secure communication systems.

Claims

1. A method for implementing block encryption integrating quantum keys, characterized in that: The sender and receiver of an IPsec system use a hybrid key, an authentication header, and an encapsulating security payload to transmit messages. The hybrid key generation method includes the following steps: Step 1: The sender and receiver generate a key SKEYID d 、SKEYID a and SKEYID e And generate corresponding quantum keys QKD keys for each VPN channel; Step 2: Divide the quantum key QKD keys into four segments of the same length to obtain QKD d , QKD a , QKD e and QKD s , change SKEYID d 、SKEYID a and SKEYID e Respectively with QKD d , QKD a and QKD e Use the extended pseudo-random function to fuse and get the new key QSKEYID d 、QSKEYID a and QSKEYID e ; The extended pseudo-random function is to call the pseudo-random function multiple times and concatenate the results of the pseudo-random function so that the generated key reaches the target length; Step 3: Use QSKEYID d Generate key material KEYMAT; Step 4: Combine KEYMAT with QKD s The mixed key is obtained by using the extended pseudo-random function fusion.

2. The method for implementing block encryption integrating quantum keys according to claim 1, characterized in that: In step 1, the sender and receiver use a pseudo-random function to generate a seed key and generate a key SKEYID based on the seed key d 、SKEYID a and SKEYID e .

3. The method for implementing block encryption integrating quantum keys according to claim 2, wherein: In step 2, the new key QSKEYID is determined based on the number of bits of the seed key d 、QSKEYID a and QSKEYID e length.

4. The method for implementing block encryption integrating quantum keys according to claim 1, wherein: In step 2, the workflow of the extended pseudo-random function is as follows: assume that any keys K and S are fused using the extended pseudo-random function, prf+(K,S)=T1|T2|T3|T4…, where: T1=prf(K,S|0x01); T2 = prf(K, T1|S|0x02); T3 = prf(K, T2|S|0x03); T4=prf(K,T3|S|0x04); prf is a pseudorandom function.

5. The method for implementing block encryption integrating quantum keys according to claim 1, wherein: The key material KEYMAT in step 3 = prf(QSKEYID d ,protocol|SPI|Ni|Nr), where protocol is the protocol number of the authentication header and encapsulating security payload protocol in the IPsec protocol, SPI is a unique identifier, and Ni and Nr are random numbers.

6. A communication system, characterized in that: Message transmission is performed using the block encryption implementation method integrating quantum keys as described in any one of claims 1 to 4.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the computer program is loaded into a processor, the method for implementing block encryption using a fused quantum key according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for implementing block encryption using a fused quantum key according to any one of claims 1 to 5 is implemented.

9. A method for evaluating a communication system according to claim 6, characterized in that: Including calculation of key consumption rate Calculate the number of supported VPN tunnels where R Q is the key rate of quantum key QKD keys, t is the key SKEYID d 、SKEYID a or SKEYID e length.

10. The communication system evaluation method according to claim 9, characterized in that: It also includes calculating the total throughput Thpt=n VPN R VPN , where R VPN The maximum data transmission rate achievable through a single VPN tunnel.

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