A Quantum Key Distribution Method and System Based on Cipher Block Chaining Mode

Abstract

The present invention discloses a quantum key distribution method and system based on the cipher block chaining mode, including the steps of: S1, a first client and a second client share an initial basis sequence and an initialization vector as a first basis sequence, a first vector, a second basis sequence, and a second vector; S2, the first client obtains a new first basis sequence according to the first basis sequence and the first vector and generates a random bit string as the new first vector. According to the first basis sequence and the first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client; S3, according to the second basis sequence and the second vector, the second client calculates to obtain a new second basis sequence, and the second client measures the quantum bit sequence according to the second basis sequence to obtain a secondary vector; S4, repeat steps S2 - S3 for a set number of times; S5, according to the error rate of the first vector and the second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

Description

Technical Field

[0001] The present invention relates to the technical field of information transmission, and particularly relates to a quantum key distribution method and system based on the cipher block chaining mode. Background Art

[0002] With the rapid development of network technology, a large amount of sensitive information needs to be transmitted through the network, and people need to protect this information from malicious attacks. Cryptography provides us with a powerful guarantee, and its security is based on the computational complexity assumption. However, the proposed quantum parallel algorithm has subverted the foundation of traditional cryptography.

[0003] Since it can solve the factorization problem and some other mathematical problems in a short time, the security of the classical cryptographic system based on computational complexity has been increasingly severely challenged. The continuous development of quantum technology has forced people to find a new cryptographic system that is secure against quantum computing. As a product of the combination of cryptography and quantum mechanics, the security of quantum cryptography is guaranteed by the basic principles of quantum mechanics and is independent of the computing power of the attacker. As the most important branch of quantum cryptography, quantum key distribution (QKD) has become a research hotspot in the current field of information security.

[0004] Quantum key distribution provides a secure method for distributing keys between two users by using the characteristics of quantum mechanics. It can be combined with the one-time pad to achieve a truly perfectly secure cryptographic system. In 1984, C.H. Bennett and G. Brassard proposed the famous first QKD protocol (BB84 protocol), which was subsequently proven to have unconditional security in theory. Inspired by this, many ingenious quantum key distribution protocols have been designed. These protocols can be roughly divided into two types. One is based on the indistinguishability of non-orthogonal states, and the other is based on the correlation of measurement results of entangled states. However, most of these protocols need to publish the measurement bases, and attackers can use this publicly available measurement base information to undermine the security of the protocol in practical applications under the cover of channel noise. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to provide a quantum key distribution method and system based on the cipher block chaining mode, which does not need to publish the measurement bases and has higher security.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is:

[0007] A quantum key distribution method based on the cipher block chaining mode, comprising the steps of:

[0008] S1. The first client and the second client share an initial base sequence and an initialization vector as the first base sequence and the first vector of the first client, and as the second base sequence and the second vector of the second client. The initial base sequence and the initialization vector are random bit strings;

[0009] S2. The first client obtains a new first base sequence based on the first base sequence and the first vector and generates a random bit string as the new first vector. According to the first base sequence and the first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client;

[0010] S3. According to the second base sequence and the second vector, the second client calculates to obtain a new second base sequence. The second client measures the quantum bit sequence according to the second base sequence to obtain a secondary vector;

[0011] S4. Repeat steps S2 - S3 for a set number of times;

[0012] S5. According to the error rate of the first vector and the second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

[0013] To solve the above technical problems, another technical solution adopted by the present invention is:

[0014] A quantum key distribution system based on the cipher block chaining mode includes a server, a first client, and a second client.

[0015] The server includes a first memory, a first processor, and a computer program stored on the first memory and executable on the first processor. The first client includes a second memory, a second processor, and a computer program stored on the second memory and executable on the second processor. The second client includes a third memory, a third processor, and a computer program stored on the third memory and executable on the third processor. When the first processor, the second processor, and the third processor execute the computer program, the following steps are implemented:

[0016] S1. The first client and the second client share an initial base sequence and an initialization vector as the first base sequence and the first vector of the first client, and as the second base sequence and the second vector of the second client. The initial base sequence and the initialization vector are random bit strings;

[0017] S2. The first client obtains a new first base sequence based on the first base sequence and the first vector and generates a random bit string as the new first vector. According to the first base sequence and the first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client;

[0018] S3. Based on the second basis sequence and the second vector, the second client calculates a new second basis sequence, and the second client measures the quantum bit sequence according to the second basis sequence to obtain a secondary vector;

[0019] S4. Repeat steps S2 - S3 for a set number of times;

[0020] S5. According to the error rates of the first vector and the second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

[0021] The beneficial effects of the present invention are as follows: A quantum key distribution method and system based on the cipher block chaining mode. The two communication parties share a bit string in advance and use it as the input of the cipher block chaining module. In this way, the two communication parties can obtain the same basis information without publicly discussing the basis information, which not only makes the protocol more secure but also greatly improves the efficiency of the protocol. Description of the Drawings

[0022] Figure 1 It is a schematic flowchart of a quantum key distribution method based on the cipher block chaining mode according to an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of data flow involved in an embodiment of the present invention;

[0024] Figure 3 It is a schematic structural diagram of a quantum key distribution system based on the cipher block chaining mode according to an embodiment of the present invention.

[0025] Label Description:

[0026] 1. A quantum key distribution system based on the cipher block chaining mode; 2. Server; 22. First processor; 23. First memory; 3. First client; 32. Second processor; 33. Second memory; 4. Second client; 42. Third processor; 43. Third memory. Detailed Embodiments

[0027] To illustrate the technical content, the achieved objectives, and the effects of the present invention in detail, the following is described in conjunction with the embodiments and the accompanying drawings.

[0028] Please refer to Figures 1 to 2 , A quantum key distribution method based on the cipher block chaining mode, including the steps:

[0029] S1. The first client and the second client share an initial basis sequence and an initialization vector, which are used as the first basis sequence and the first vector of the first client, and as the second basis sequence and the second vector of the second client. The initial basis sequence and the initialization vector are random bit strings;

[0030] S2. The first client obtains a new first basis sequence based on the first basis sequence and the first vector, generates a random bit string as the new first vector. According to the first basis sequence and the first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client;

[0031] S3. According to the second basis sequence and the second vector, the second client calculates to obtain a new second basis sequence. The second client measures the quantum bit sequence according to the second basis sequence to obtain a secondary vector;

[0032] S4. Repeat steps S2 - S3 for a set number of times;

[0033] S5. According to the error rates of the first vector and the second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

[0034] As can be seen from the above description, the beneficial effects of the present invention are as follows: A quantum key distribution method and system based on the cipher block chaining mode. The two communication parties share a bit string in advance and use it as the input of the cipher block chaining module. In this way, the two communication parties can obtain the same basis information without publicly discussing the basis information, which not only makes the protocol more secure but also greatly improves the efficiency of the protocol.

[0035] Further, the specific steps of step S1 include:

[0036] The server distributes a 2n - bit key K to the first client and the second client through the BB84 protocol. The first client generates an n - bit random bit string initial basis sequence and an n - bit random bit string initialization vector. The first client encrypts the initial basis sequence and the initialization vector with the key K and transmits them to the second client.

[0037] As can be seen from the above description, secure sharing of the initial basis sequence and the initialization vector is achieved.

[0038] Further, the specific steps of step S2 include:

[0039] The first client calculates a new first basis sequence according to the first basis sequence and the first vector wherein, The first client generates a new n - bit first vector According to B1 and S1, prepares an n - bit quantum bit string Q1, and the quantum bit string Q1 is in the quantum state and sends Q1 to the second client through a public quantum channel;

[0040] The specific steps of step S3 include: ​

[0041] The second client calculates a new second base sequence based on the second base sequence and the second vector wherein the second client measures the quantum bit string Q1 according to the second base sequence to obtain a new second vector S1. As can be seen from the above description, it is realized that both communication parties can obtain the same base information without publicly discussing the base information.

[0042] Furthermore, the bit string Q1 is in a quantum state

[0043] Specifically in step S3, the specific process of measuring the quantum bit string Q1 according to the second base sequence to obtain a new second vector S1 is as follows:

[0044] When

[0045] the second client measures the j-th quantum using the Z basis; when the second client measures the j-th quantum using the X basis. As can be seen from the above description, the measurement of the quantum bit string is realized.

[0046] Furthermore, after step S4 is repeatedly executed for a set number of times of steps S2 - S3, the following is also executed:

[0047] The first client and the second client publicly compare random subsets of the first vector and the second vector that are longer than the set length. If the error rate is higher than the set value, the execution stops; otherwise, step S5 is executed.

[0048] As can be seen from the above description, the security is further enhanced.

[0049] A quantum key distribution system based on the cipher block chaining mode includes a server, a first client, and a second client.

[0050] The server includes a first memory, a first processor, and a computer program stored on the first memory and executable on the first processor. The first client includes a second memory, a second processor, and a computer program stored on the second memory and executable on the second processor. The second client includes a third memory, a third processor, and a computer program stored on the third memory and executable on the third processor. When the first processor, the second processor, and the third processor execute the computer program, the following steps are implemented:

[0051]

[0052] ​S1. The first client and the second client share an initial base sequence and an initialization vector as the first base sequence and the first vector of the first client, and as the second base sequence and the second vector of the second client. The initial base sequence and the initialization vector are random bit strings;

[0053] S2. The first client obtains a new first base sequence based on the first base sequence and the first vector and generates a random bit string as the new first vector. According to the first base sequence and the first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client;

[0054] S3. According to the second base sequence and the second vector, the second client calculates to obtain a new second base sequence. The second client measures the quantum bit sequence according to the second base sequence to obtain a secondary vector;

[0055] S4. Repeat steps S2 - S3 for a set number of times;

[0056] S5. According to the error rate of the first vector and the second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

[0057] As can be seen from the above description, the beneficial effect of the present invention is that: a quantum key distribution method and system based on the cipher block chaining mode, where the two communication parties share a bit string in advance and use it as the input of the cipher block chaining module. In this way, the two communication parties can obtain the same base information without publicly discussing the base information, which not only makes the protocol more secure but also greatly improves the efficiency of the protocol.

[0058] Further, step S1 specifically includes:

[0059] The server distributes a 2n - long key K to the first client and the second client through the BB84 protocol. The first client generates an n - long random bit string initial base sequence and an n - long random bit string initialization vector. The first client encrypts the initial base sequence and the initialization vector with the key K and transmits them to the second client.

[0060] As can be seen from the above description, secure sharing of the initial base sequence and the initialization vector is achieved.

[0061] Further, step S2 specifically includes:

[0062] The first client calculates a new first base sequence according to the first base sequence and the first vector to obtain a new first base sequence where the first client generates a new n - long first vector According to B1 and S1, prepare an n-length qubit string Q1, and the qubit string Q1 is in the quantum state and send Q1 to the second client through a public quantum channel;

[0063] The specific steps of step S3 include:

[0064] The second client calculates a new second basis sequence according to the second basis sequence and the second vector where, The second client measures the qubit string Q1 according to the second basis sequence to obtain a new second vector S1.

[0065] As can be seen from the above description, it is realized that both communication parties can obtain the same basis information without publicly discussing the basis information.

[0066] Further, the bit string Q1 is in the quantum state Specifically

[0067] In step S3, when measuring the qubit string Q1 according to the second basis sequence to obtain a new second vector S1, specifically:

[0068] When , the second client measures the j-th qubit using the Z basis; when , the second client measures the j-th qubit using the X basis.

[0069] As can be seen from the above description, the measurement of the qubit string is realized.

[0070] Further, after step S4 repeats steps S2 - S3 for a set number of times, it also executes:

[0071] The first client and the second client publicly compare random subsets of the first vector and the second vector that are longer than the set length. If the error rate is higher than the set value, stop the execution; otherwise, execute step S5.

[0072] As can be seen from the above description, the security is further enhanced.

[0073] The present invention is applied to encrypted communication between two terminals in various scenarios.

[0074] Figures 1 to 2 Please refer to , and the first embodiment of the present invention is:

[0075] A quantum key distribution method based on the cipher block chaining mode, four non-orthogonal states It is used as an information carrier and transmitted between two users. The two users first negotiate an initial message through a secure quantum key distribution protocol (such as BB84), and then use this initial message to securely distribute round keys. Next, in each round of key distribution, the key of the previous round is combined with the CBC technology to obtain the base information of the current round. On this basis, the key of this round is distributed. The above process is continuously executed until a sufficiently long raw key is obtained.

[0076] Specifically, it includes:

[0077] Step S1: The first user terminal and the second user terminal share an initial basis sequence and an initialization vector, which are used as the first basis sequence and the first vector of the first user terminal, and the second basis sequence and the second vector of the second user terminal. The initial basis sequence and the initialization vector are pre-generated random bit strings.

[0078] Specifically, let there be a first user terminal Alice and a second user terminal Bob. Through the BB84 protocol, Alice and Bob securely distribute a key K of length 2n. Then, Alice prepares two random bit strings of length n. One is the basis sequence The other is the initialization vector Finally, Alice uses the one-time pad method to encrypt the two sequences B0 and S0 with the key K and securely transmits these two sequences to Bob.

[0079] Step S2: The first user terminal obtains a new first basis sequence according to the first basis sequence and the first vector, and generates a random bit string as the new first vector. According to the first basis sequence and the first vector, the first user terminal prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second user terminal.

[0080] Specifically, according to the two sequences B0 and S0, Alice calculates the basis sequence of the first round where, Then, she generates a random bit string of length n and uses it as the round key of the first round. Finally, Alice prepares an n-length quantum bit string Q1 in the quantum state according to the two bit strings B1 and S1 and sends Q1 to Bob through an open quantum channel. Here,

[0081] Step S3: According to the second basis sequence and the second vector, the second user terminal calculates a new second basis sequence, and the second user terminal measures the quantum bit sequence according to the second basis sequence to obtain a secondary vector.

[0082] Specifically, after receiving these n qubits, Bob publicly confirms the receipt of these qubits. Then, according to sequences B0 and S0, Bob calculates the sub-basis sequence B1 for the first round. Then, he selects an appropriate basis for measurement according to this sub-basis sequence. Specifically, when occurs, Bob measures the j-th qubit using the Z basis and records the measurement result; when occurs, Bob measures the j-th qubit using the X basis. Obviously, in the ideal case, the measurement result is equal to the round key S1 for the first round, that is, the new first vector is equal to the new second vector. In this way, Bob obtains S1.

[0083] Step S4: Repeat steps S2 - S3 for a set number of times.

[0084] By executing the above two steps (S2 and S3) for multiple rounds, users Alice and Bob can obtain a sufficiently long raw key. During the eavesdropping detection process, users Alice and Bob publicly compare a sufficiently large random subset of their bit sequences. If the error rate is too high, they will abort the protocol.

[0085] Specifically, step (2i) (i = 2, 3,..., m): According to the two sequences B i-1 and S i-1 , Alice calculates to obtain the basis sequence for the i-th round. Then, she generates an n-length random bit string and uses it as the round key for the i-th round. Finally, Alice prepares a qubit string Q i and S i , and prepares a qubit string Q i in the quantum state and sends these n qubits to Bob through a public quantum channel.

[0086] Step (2i + 1) (i = 2, 3,..., m): According to the sequences B i-1 and S i-1 , Bob calculates the basis sequence B i for the i-th round. Then, he selects an appropriate basis for projective measurement on the received qubits and records the measurement result S i .

[0087] Step (2m + 2): Through the above steps, Alice and Bob have distributed a raw key S of length m × n = {S1, S2,... S m}. Next, the two participants perform eavesdropping detection. Specifically, Alice and Bob publicly compare a sufficiently large random subset of their bit sequences. If the error rate is higher than a pre-set threshold, they abort the protocol; otherwise, they execute step S5.

[0088] Step S5: According to the error rate, the first client and the second client perform classical error correction coding (such as BCH code, etc.) and privacy amplification to generate a secure key.

[0089] The method of generating a secure key based on error correction coding and privacy amplification is a prior art and will not be elaborated here.

[0090] Please refer to Figure 3 , Embodiment 2 of the present invention is:

[0091] A quantum key distribution system 1 based on the cipher block chaining mode, comprising a server 2, a first client 3, and a second client 4.

[0092] The server 2 includes a first memory 23, a first processor 22, and a computer program stored on the first memory 23 and executable on the first processor 22. The first client 3 includes a second memory 33, a second processor 32, and a computer program stored on the second memory 33 and executable on the second processor 32. The second client 4 includes a third memory 43, a third processor 42, and a computer program stored on the third memory 43 and executable on the third processor 42.

[0093] When the first processor 22, the second processor 32, and the third processor 42 execute the computer program, they implement the steps of the above-mentioned Embodiment 1.

[0094] In summary, for a quantum key distribution method and system provided by the present invention, the two communicating parties share a bit string in advance and use it as the input of the cipher block chaining module. In this way, the two communicating parties can obtain the same basis information without publicly discussing the basis information, which not only makes the protocol more secure but also greatly improves the efficiency of the protocol.

[0095] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent transformation made using the content of the specification and drawings of the present invention, or directly or indirectly applied in the related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A quantum key distribution method based on the cipher block chaining mode, characterized in that Including the steps: S1. The first client and the second client share an initial basis sequence and an initialization vector, which are used as the first basis sequence and the first vector of the first client, and as the second basis sequence and the second vector of the second client. The initial basis sequence and the initialization vector are random bit strings; S2. The first client obtains a new first basis sequence based on the first basis sequence and the first vector, generates a random bit string as the new first vector. According to the new first basis sequence and the new first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client; S3. According to the second basis sequence and the second vector, the second client calculates to obtain a new second basis sequence. The second client measures the quantum bit sequence according to the new second basis sequence to obtain a new second vector; S4. Repeat steps S2 - S3 for a set number of times; S5. According to the error rate of the new first vector and the new second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

2. The quantum key distribution method based on the cipher block chaining mode according to claim 1, wherein, The specific content of step S1 includes: The server distributes a key K with a length of 2n to the first client and the second client through the BB84 protocol. The first client generates a random bit string initial basis sequence with a length of n and a random bit string initialization vector with a length of n. The first client encrypts the initial basis sequence and the initialization vector with the key K and transmits them to the second client.

3. A quantum key distribution method based on the cipher block chaining mode according to claim 2, characterized in that, The specific content of step S2 includes: The first client calculates a new first base sequence according to the first base sequence and the first vector . Among them, , the first client generates a new first vector of length n . According to and and , a quantum bit string of length n is prepared. The quantum bit string is in the quantum state , and is sent to the second client through an open quantum channel; The specific content of step S3 includes: The second client calculates a new second base sequence based on the second base sequence and the second vector , where . The second client measures the qubit string based on the second base sequence to obtain a new second vector .​ 4. A quantum key distribution method based on the cipher block chaining mode according to claim 3, characterized in that The qubit string is in a quantum state Specifically , , , ; In the step S3, a new second vector is obtained by measuring the qubit string according to the second base sequence Specifically: When = 0, the second client measures the j-th quantum using the Z basis; when = 1, the second client measures the j-th quantum using the X basis.

5. A quantum key distribution method based on the cipher block chaining mode according to claim 1, characterized in that After repeating steps S2 - S3 for a set number of times, step S4 also performs: The first client and the second client publicly compare a random subset of the first vector and the second vector that is longer than the set length. If the error rate is higher than the set value, stop the execution. Otherwise, execute step S5.

6. A quantum key distribution system based on the cipher block chaining mode, including a server, a first client, and a second client; The server includes a first memory, a first processor, and a computer program stored on the first memory and executable on the first processor. The first client includes a second memory, a second processor, and a computer program stored on the second memory and executable on the second processor. The second client includes a third memory, a third processor, and a computer program stored on the third memory and executable on the third processor, characterized in that When the first processor, the second processor, and the third processor execute the computer program, the following steps are implemented: S1. The first client and the second client share an initial basis sequence and an initialization vector, which are used as the first basis sequence and the first vector of the first client, and as the second basis sequence and the second vector of the second client. The initial basis sequence and the initialization vector are random bit strings; S2. The first client obtains a new first basis sequence based on the first basis sequence and the first vector, generates a random bit string as the new first vector. According to the new first basis sequence and the new first vector, the first client prepares a corresponding quantum bit sequence and sends the quantum bit sequence to the second client; S3. According to the second basis sequence and the second vector, the second client calculates to obtain a new second basis sequence. The second client measures the quantum bit sequence according to the new second basis sequence to obtain a new second vector; S4. Repeat steps S2 - S3 for a set number of times; S5. According to the error rate of the new first vector and the new second vector, the first client and the second client perform error correction and privacy amplification to generate a secure key.

7. A quantum key distribution system based on the cipher block chaining mode according to claim 6, characterized in that, The specific steps of step S1 include: The server distributes a 2n-length key K to the first client and the second client through the BB84 protocol. The first client generates an n-length random bit string initial basis sequence and an n-length random bit string initialization vector. The first client encrypts the initial basis sequence and the initialization vector with the key K and transmits them to the second client.

8. A quantum key distribution system based on the cipher block chaining mode according to claim 7, characterized in that The specific steps of step S2 include: The first client calculates a new first base sequence according to the first base sequence and the first vector . Among them, , the first client generates a new first vector of length n . According to and , a quantum bit string of length n is prepared . The quantum bit string is in the quantum state , and is sent to the second client through an open quantum channel;​ The specific steps of step S3 include: The second client calculates a new second base sequence according to the second base sequence and the second vector . Among them, , the second client measures the qubit string according to the second base sequence to obtain a new second vector .​ 9. A quantum key distribution system based on the cipher block chaining mode according to claim 8, characterized in that, The qubit string is in a quantum state Specifically , , , ; In the step S3, according to the second base sequence, the qubit string is measured to obtain a new second vector Specifically: When = 0, the second client measures the j-th quantum using the Z basis; when = 1, the second client measures the j-th quantum using the X basis.

10. A quantum key distribution system based on the cipher block chaining mode according to claim 6, characterized in that, After step S4 repeats steps S2 - S3 for a set number of times, it also executes: The first client and the second client publicly compare a random subset of the first vector and the second vector that is greater than the set length. If the error rate is higher than the set value, the execution stops; otherwise, step S5 is executed.

Images