CN111404673B

CN111404673B - Quantum key distribution method and device

Info

Publication number: CN111404673B
Application number: CN201910001350.2A
Authority: CN
Inventors: 刘福文; 马冰柯; 阎军智
Original assignee: China Mobile Communications Group Co Ltd; China Mobile Communications Ltd Research Institute
Current assignee: China Mobile Communications Group Co Ltd; China Mobile Communications Ltd Research Institute
Priority date: 2019-01-02
Filing date: 2019-01-02
Publication date: 2023-05-09
Anticipated expiration: 2039-01-02
Also published as: CN111404673A

Abstract

The embodiment of the invention discloses a method and equipment for quantum key distribution, which are used for solving the problem of lower quantum key distribution safety in a quantum communication process. When the embodiment of the invention distributes the quantum key, firstly, the sending equipment brings the key parameter value for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value; and finally, the sending device sends the at least one sending parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one sending parameter value and the function value. When the method is used for transmission, at least one transmission parameter value in the polynomial function and the polynomial function value obtained correspondingly are transmitted, so that even if a quantum channel for transmission is unreliable, an attacker can not obtain a session key in the transmission process, and the transmission safety of the quantum key is improved.

Description

Quantum key distribution method and device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and apparatus for quantum key distribution.

Background

With the rapid development of society, national security and business security are increasingly emphasized, a cryptographic algorithm is a core technology for guaranteeing information security, the cryptographic algorithm is mainly a mathematical function for encryption and decryption, and the current cryptographic algorithm mainly comprises a sequence cipher, a block cipher, a public key cipher, a hash function and the like and is used for guaranteeing information security and providing services such as authentication, integrity, repudiation resistance and the like, wherein the security of one cryptographic system is only in the confidentiality of a secret key, but not in the confidentiality of the algorithm.

But currently the security of many classical cryptographic algorithms is facing an increasingly serious challenge due to the rapid development of quantum computing technology. The quantum computing technology has different effects on an asymmetric cryptographic algorithm and a symmetric cryptographic algorithm. Quantum computing technology has a great impact on the asymmetric algorithms based on computational complexity that are currently in widespread use, in particular, all of which can be rendered ineffective. While most systems now use symmetric key algorithms for data protection, the keys used by them are generated in dependence on asymmetric algorithms, which would pose a serious threat to current security systems.

Meanwhile, under the prospect of development of quantum computing technology, a quantum key distribution technology is proposed, and the quantum key distribution technology is a key technology capable of guaranteeing safe key distribution in quantum age. The method replaces the existing asymmetric algorithm to realize key negotiation, and can enable the existing security system to be used continuously in quantum age. However, the current quantum key distribution technology still has the problem of low security, and meanwhile, due to the self-characteristics of the quantum, many weaknesses exist. For example, because quantum communication uses single photons as carriers, the communication distance of the single photons is generally not more than 200 km and can only be transmitted in a short distance, which limits the application range of the key distribution system, in consideration of attenuation of the single photons in a fiber channel and sensitivity of a detector. In addition, in the quantum communication process, the communication is easily blocked, and the state is suddenly changed when the quantum is measured, so that the communication is stopped when both communication parties find that the state is changed.

In summary, the quantum key distribution security in the current quantum communication process is relatively low.

Disclosure of Invention

The embodiment of the invention provides a method and equipment for quantum key distribution, which are used for solving the problem of lower quantum key distribution safety in a quantum communication process.

In a first aspect, a method for quantum key distribution provided by an embodiment of the present invention includes:

firstly, a transmitting device brings key parameter values for determining a quantum key and at least one transmitting parameter value into a polynomial function to obtain a function value; and finally, the sending device sends the at least one sending parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one sending parameter value and the function value.

According to the method, when transmission is carried out, at least one transmission parameter value in the polynomial function and the polynomial function value obtained correspondingly are transmitted, so that even if a quantum channel for transmission is unreliable, an attacker cannot obtain a session key in the transmission process, and the transmission safety of the quantum key is improved.

In one possible implementation, the sending device is a single channel transmission; the sending device brings key parameter values for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value; the transmitting device transmits the at least one transmission parameter value and the one function value to the receiving device through the single channel.

According to the method, when the transmission is carried out through a single channel, at least one transmission parameter value in the polynomial function and the polynomial function value obtained correspondingly are transmitted, so that even if a quantum channel for transmission is unreliable, an attacker cannot obtain a session key in the transmission process, and the quantum key transmission safety is improved.

In one possible implementation, the sending device is a multi-channel transmission; the sending equipment brings key parameter values for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values; the transmitting device transmits the at least one transmission parameter value and the at least one function value to the receiving device through each channel, respectively.

According to the method, when the transmission is carried out through the multiple channels, at least one transmission parameter value in the polynomial function and the polynomial function value obtained correspondingly are transmitted, so that even if the quantum channel for transmission is unreliable, an attacker cannot obtain a session key in the transmission process, and the quantum key transmission safety is improved. Meanwhile, due to the fact that multiple quantum channel key distribution is adopted, the reliability of quantum key generation can be improved, the sending equipment brings key parameter values for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values, the at least two function values are respectively transmitted to the other party through different quantum channels, if in the distribution process, even if one quantum channel is interfered, communication of the whole quantum communication system is not affected, stability of transmission is improved, and success rate of transmission is higher.

In one possible implementation, the transmitting device brings the key parameter values for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain a function value; the transmitting device transmits the at least one transmission parameter value and the corresponding one function value to the receiving device through each channel, respectively.

According to the method, when the transmission is carried out through multiple channels, the transmitting equipment transmits at least one transmitting parameter value and one function value to each channel, so that even if a quantum channel for transmission is not credible, an attacker cannot obtain a session key in the transmission process, and the quantum key transmission safety is improved. Meanwhile, due to the adoption of multi-quantum channel key distribution, when one quantum channel is interfered, the communication of the whole quantum communication system is not affected, the stability of transmission is improved, and the success rate of transmission is higher.

In one possible implementation, the transmitting device determines a plurality of sets of transmission parameter values; for any group of transmission parameter values, the transmission device brings the key parameter value for determining the quantum key and the transmission parameter value into a polynomial function to obtain a function value, and transmits the obtained function value and the at least one transmission parameter value used for obtaining the function value to the receiving device through a channel; wherein the function values for different channel transmissions are derived from different sets of transmission parameter values.

In the method, when the transmission is performed through multiple channels, firstly, the transmitting device determines multiple groups of transmission parameter values, then, for any group of transmission parameter values, the transmitting device brings the key parameter value for determining the quantum key and the transmission parameter value into a polynomial function to obtain a function value, which is equivalent to multiple encryption, so that even if the quantum channel for transmission is not credible, an attacker cannot obtain a session key in the transmission process, and the transmission safety of the quantum key is improved. Meanwhile, due to the adoption of multi-quantum channel key distribution, when one quantum channel is interfered, the communication of the whole quantum communication system is not affected, the stability of transmission is improved, and the success rate of transmission is higher.

In one possible implementation, the polynomial functions carried in by the different sets are identical.

The method has the advantages that the polynomial functions brought by different groups are the same, and the operation is simpler.

In one possible implementation, the transmitting device transmits the at least one transmission parameter value and the function value to the receiving device via the relay station.

According to the method, the sending equipment sends the at least one sending parameter value and the function value to the receiving equipment through the relay station, and the relay station is used for transmission, so that the problem of short-distance transmission of quantum communication is effectively solved.

In a second aspect, a method for quantum key distribution provided by an embodiment of the present invention includes:

firstly, a receiving device receives at least one function value sent by a sending device and obtains the at least one sending parameter value used by the function value; then the receiving equipment brings the received function value and the at least one sending parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; and finally, the receiving equipment determines a quantum key according to the obtained key parameter value.

In one possible implementation, the receiving device is a single channel receiver; the receiving device receives one function value sent by the sending device through a single channel and obtains the at least one sending parameter value used by the function value; the receiving device brings the received one function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value.

According to the method, when receiving through the single channel, at least one sending parameter value in the polynomial function and the polynomial function value obtained correspondingly are received, so that even if a quantum channel for transmission is unreliable, an attacker cannot obtain a session key in the transmission process, and the quantum key transmission safety is improved.

In one possible implementation, the receiving device is a multi-channel receiver; for any channel, the receiving device receives a function value sent by the sending device and the at least one sending parameter value used for obtaining the function value through the channel; the receiving device brings at least one function value received by the same quantum channel and the at least one sending parameter value into a corresponding polynomial function to obtain a key parameter value.

According to the method, when the receiving is carried out through the multiple channels, at least one sending parameter value in the polynomial function and the polynomial function value obtained correspondingly are received, so that even if the quantum channel for transmission is unreliable, an attacker can not obtain a session key in the transmission process, and the quantum key transmission safety is improved.

In one possible implementation manner, if the key parameter values obtained by the receiving device are multiple, the receiving device synthesizes the multiple obtained key parameter values to obtain a quantum key; or alternatively, the first and second heat exchangers may be,

and if the key parameter values obtained by the receiving equipment are 1, the receiving equipment determines the key parameter values as quantum keys.

According to the method, the receiving equipment determines the quantum key according to different quantity of the received key parameter values, if the number of the key parameter values obtained by the receiving equipment is multiple, the plurality of key parameter values are synthesized to obtain the quantum key, and if the number of the key parameter values obtained by the receiving equipment is 1, the key parameter value is determined to be the quantum key, so that the adaptability is stronger.

In one possible implementation, if the receiving device determines that some of the quantum channels that receive are interfered, the receiving device synthesizes a quantum key from key parameter values obtained from function values and transmission parameter values received through the quantum channels that are not interfered.

According to the method, the receiving equipment synthesizes the key parameter values obtained through the function values received by the quantum channels without interference and the sending parameter values into the quantum key, so that the accuracy of the obtained quantum key is higher.

In a third aspect, an embodiment of the present invention provides a device for quantum key distribution, including: processor and transceiver:

the processor is used for bringing the key parameter value for determining the quantum key and at least one transmission parameter value into a polynomial function through the transceiver to obtain a function value; and transmitting the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value.

In a fourth aspect, an embodiment of the present invention provides a device for quantum key distribution, including: processor and transceiver:

the processor is configured to receive, through a transceiver, at least one function value sent by a sending device and obtain the at least one sending parameter value used by the function value; bringing the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; and determining a quantum key according to the obtained key parameter value.

In a fifth aspect, an embodiment of the present invention further provides a device for quantum key distribution, the device including:

at least one processing unit and at least one storage unit, wherein the storage unit stores program code which, when executed by the processing unit, causes the processing unit to perform the functions of the embodiments of the first aspect described above.

In a sixth aspect, an embodiment of the present invention further provides a device for quantum key distribution, the device including:

at least one processing unit and at least one storage unit, wherein the storage unit stores program code which, when executed by the processing unit, causes the processing unit to perform the functions of the embodiments of the second aspect described above.

In a seventh aspect, the present application also provides a computer storage medium having stored thereon a computer program which when executed by a processor performs the steps of the method of the first aspect.

In an eighth aspect, the present application also provides a computer storage medium having stored thereon a computer program which when executed by a processor performs the steps of the method of the second aspect.

In addition, technical effects caused by any implementation manner of the third aspect to the eighth aspect may be referred to technical effects caused by different implementation manners of the first aspect to the second aspect, and are not described herein.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it will be apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a system architecture for quantum key distribution according to an embodiment of the present invention;

fig. 2 is a schematic diagram of transmission from a transmitting device to a receiving device through a single channel according to an embodiment of the present invention;

fig. 3 is a schematic diagram illustrating transmission of a transmitting device to a receiving device through multiple channels according to an embodiment of the present invention;

fig. 4 is a schematic diagram of the same transmission information of each channel when a sending device performs transmission to a receiving device in multiple channels according to an embodiment of the present invention;

fig. 5 is a schematic diagram of different channel transmission information when a sending device transmits to a receiving device in multiple channels according to an embodiment of the present invention;

fig. 6 is a schematic diagram of single-channel transmission from a transmitting device to a receiving device through a relay station according to an embodiment of the present invention;

fig. 7 is a schematic diagram of multi-channel transmission from a transmitting device to a receiving device through a relay station according to an embodiment of the present invention;

Fig. 8 is a schematic diagram of a device structure for quantum key distribution according to a first embodiment of the present invention;

fig. 9 is a schematic diagram of a second device structure for quantum key distribution according to an embodiment of the present invention;

fig. 10 is a schematic diagram of an apparatus structure for quantum key distribution according to a third embodiment of the present invention;

FIG. 11 is a schematic diagram of a fourth device for quantum key distribution according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a method of quantum key distribution according to a first embodiment of the present invention;

FIG. 13 is a schematic diagram of a method of quantum key distribution according to a second embodiment of the present invention;

fig. 14 is a flow chart of a method for quantum key distribution according to an embodiment of the present invention.

Detailed Description

For the purpose of promoting an understanding of the principles and advantages of embodiments of the invention, reference will now be made in detail to the embodiments of the invention, some but not all of which are illustrated in the accompanying drawings. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the embodiments of the present invention.

Some words appearing hereinafter are explained:

(1) The term "plurality" in the embodiments of the present application means two or more, and other adjectives are similar thereto.

(2) "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship.

(3) The relay station refers to a device responsible for receiving and forwarding quantum key parameters.

(4) The "key" referred to in the embodiments of the present invention is a parameter that is input in an algorithm for converting plaintext into ciphertext or converting ciphertext into plaintext. The keys are classified into symmetric keys and asymmetric keys.

(5) The "quantum" referred to in the embodiments of the present invention mainly refers to a physical quantity, which is quantized if it has a minimum unit but is discontinuous, and refers to the minimum unit as quantum.

(6) The quantum key distribution referred to by the embodiment of the invention is mainly based on quantum physics and informatics and is considered as an encryption mode with highest security, and the quantum key distribution can provide unconditionally secure shared keys for users separated by two places.

(7) The cryptographic algorithm is a mathematical function for encryption and decryption, the cryptographic algorithm is the basis of a cryptographic protocol, and the current cryptographic algorithm mainly comprises a sequence cipher, a block cipher, a public key cipher, a hash function and the like, and is used for guaranteeing the safety of information and providing services such as authentication, integrity, anti-repudiation and the like.

(8) The asymmetric cryptographic algorithm is a secret method of a secret key, and two secret keys, namely a public key and a private key, are needed. The asymmetric cryptosystem is characterized in that the algorithm strength is complex, the security depends on the algorithm and the secret key, but the encryption and decryption speeds are not as fast as those of symmetric encryption and decryption due to the complex algorithm.

(9) The "symmetric cryptographic algorithm" referred to in the embodiments of the present invention refers to an encryption algorithm that encrypts and decrypts using the same key. The symmetric encryption algorithm has the characteristics of open algorithm, small calculated amount, high encryption speed and high encryption efficiency.

(10) The "polynomial" referred to in the embodiments of the present invention refers to an expression obtained by variables, coefficients, and addition, subtraction, multiplication, and exponentiation operations (non-negative integer powers) therebetween in mathematics.

(11) The hash function is mainly used for encryption algorithm in the field of information security, and converts information with different lengths into scrambled 128-bit codes called hash values.

As shown in fig. 1, an embodiment of the present invention provides a system for quantum key distribution, the system comprising:

a transmitting device 100 for bringing key parameter values for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain a function value by means of a transceiver; and transmitting the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value.

A receiving device 101 for receiving, via the transceiver, at least one function value transmitted by the transmitting device and obtaining the at least one transmission parameter value used by the function value; bringing the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; and determining a quantum key according to the obtained key parameter value.

By the method, when transmission is carried out, at least one transmission parameter value in the polynomial function and the polynomial function value obtained correspondingly are transmitted, so that even if a quantum channel for transmission is unreliable, an attacker cannot obtain a session key in the transmission process, and the transmission safety of the quantum key is improved.

The embodiment of the invention mainly realizes encryption through a polynomial function, then the sending equipment sends at least one sending parameter value and the function value in the polynomial function to the receiving equipment, and the receiving equipment brings the received at least one sending parameter value and the function value into the polynomial function, so that a key parameter value is obtained. Therefore, it is first necessary to determine a polynomial function, wherein both the transmitting device and the receiving device know the polynomial function determined.

The following describes the present invention by way of a polynomial function, and it should be noted that any polynomial function that can be applied to the present invention falls within the scope of the present invention.

f(x)＝a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function equation 1

May also be abbreviated as:

wherein the parameter a in the polynomial function is assumed ₀ A is a key parameter ₀₁ 、a ₀₂ 、…a _0n System parameters agreed in advance for the sender and the receiver.

It should be noted that how the transmitting device transmits the transmission parameter value to the receiving device may be determined according to a communication protocol between the transmitting device and the receiving device.

The number of channels for the transmitting device to transmit to the receiving device is different, and the transmission modes are also different, so that the transmitting device can be divided into various cases, and the following description will be made respectively.

Channel case 1: as shown in fig. 2, the transmitting device transmits to the receiving device through a single channel.

Specifically, the sending device is single-channel transmission; the sending device brings key parameter values for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value; the transmitting device transmits the at least one transmission parameter value and the one function value to the receiving device through the single channel.

For example, the polynomial functionFor f (x) =a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p, wherein said transmitting device and said receiving device are aware of parameter a ₁ 、a ₂ 、…a _t-1 P.

The transmitting device will randomly generate a ₀ As key parameter, the transmitting device then sets an x value by comparing the a ₀ And (3) carrying the value of (c) and the value of x into the polynomial function, and calculating to obtain a polynomial value f (x).

Finally, the transmitting device uses a single quantum channel to communicate the x value and the f (x) value to the receiving device.

Wherein the x value may be from [1, P ] ]Randomly determined, the P value is generally 2 ¹²⁸ 。

Channel case 2: as shown in fig. 3, the transmitting device transmits to the receiving device through multiple channels.

Specifically, the sending device is a multi-channel transmission; the sending equipment brings key parameter values for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values; the transmitting device transmits the at least one transmission parameter value and the at least one function value to the receiving device through each channel, respectively.

When the transmission is carried out through multiple channels, at least two transmission parameter values in the polynomial function and the polynomial function values obtained correspondingly are transmitted, so that even if the quantum channel for transmission is unreliable, the transmission process can be attacked, an attacker can not obtain a session key, and the transmission safety of the quantum key is improved. Meanwhile, due to the fact that multiple quantum channel key distribution is adopted, the reliability of quantum key generation can be improved, the sending equipment brings key parameter values for determining the quantum keys and at least two sending parameter values into a polynomial function to obtain at least two function values, and the at least two function values are respectively transmitted to the other party through different quantum channels.

When the sending device transmits to the receiving device through multiple channels, the sending device and the receiving device can be further divided into multiple cases according to whether the polynomial function for quantum key distribution set by the sending device and the receiving device is unique, which are described below.

Case 1: the sending device and the receiving device set the polynomial function for quantum key distribution.

When the polynomial function for quantum key distribution set by the sending device and the receiving device is unique, the sending device may be further divided into multiple cases according to whether the transmission information sent to the receiving device by the sending device through multiple channels is the same, which are described below.

Transmission scheme 1: as shown in fig. 4, when the transmitting device transmits to the receiving device through multiple channels, the transmission information of each channel is the same.

Specifically, the sending device brings the key parameter value for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value; the transmitting device transmits the at least one transmission parameter value and the one function value to the receiving device through each channel, respectively.

For example, the polynomial function is f (x) =a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p, wherein said transmitting device and said receiving device are aware of parameter a ₁ 、a ₂ 、…a _t-1 P.

The transmitting device will a ₀ As key parameter, and determines key parameter a ₀ Then the transmitting device sets a value of x by comparing the value of a with the value of ₀ And (3) carrying the value of (c) and the value of x into the polynomial function, and calculating to obtain a polynomial value f (x).

Finally, the transmitting device uses multiple quantum channels to respectively pass the x value and the f (x) value to the receiving device.

Transmission information 2: as shown in fig. 5, the transmission information transmitted by the transmitting device to the receiving device through multiple channels is different.

Specifically, the sending device brings the key parameter value for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values, and the sending device sends the at least one sending parameter value and the corresponding one function value to the receiving device through each channel.

For example, the polynomial function is

The transmitting device will a ₀ As key parameters and three sets of key parameters a are determined ₀ The values of a are respectively a ₀₁ 、a ₀₂ 、a ₀₃ It is assumed that the transmitting device transmits to the receiving device via three channels, wherein the transmitting device and the receiving device know the parameter a ₁ 、a ₂ 、…a _t-1 The value of p, then the transmission is from [1, p]3 numbers are randomly selected as transmission parameters, namely X1, X2 and X3./>

For any one of the transmission parameters, the transmission device brings the key parameter value for determining the quantum key and the transmission parameter value into the following corresponding polynomial function, respectively:

thereby three function values f (x 1), f (x 2), f (x 3) are obtained and the at least one transmission parameter value used for obtaining one function value and obtaining the auxiliary parameter value is transmitted to the receiving device via three channels, respectively: (f (x 1), (f (x 2), x 2) … (f (xn), xn).

Case 2: the sending device and the receiving device set a plurality of polynomial functions for quantum key distribution.

In the embodiment of the present invention, when the polynomial function for quantum key distribution set by the sending device and the receiving device is plural, the quantum channels used for transmission may be marked, so that when the sending device performs transmission, it may determine which quantum channel to use for transmission according to the correspondence between the quantum channel mark and the polynomial function as shown in table 1.

After the receiving device receives the at least one sending parameter value and the function value sent by the sending device, it can determine which polynomial function to use for calculation according to the corresponding relation between the quantum channel mark and the polynomial function, and determine the key parameter.

Quantum channel	Polynomial function
		Quantum channel A	Polynomial function 1
Quantum channel B	Polynomial function 2
		Quantum channel C	Polynomial function 3
Quantum channel D	Polynomial function 4

TABLE 1 correspondence between quantum channel markers and polynomial functions

Wherein the transmitting device transmits the at least one transmission parameter value and the function value to the receiving device through a relay station, and the number of the relay stations may be plural. As shown in fig. 6, the transmitting device transmits to the receiving device through a single channel of the relay station, and as shown in fig. 7, the transmitting device transmits to the receiving device through multiple channels of the relay station.

In the embodiment of the present invention, after the sending device sends at least one sending parameter value and the function value to the receiving device through a channel, the receiving device receives at least one function value sent by the sending device and obtains the at least one sending parameter value used by the function value.

The number of channels received by the receiving device is different, and the subsequent operation modes are also different, so that the receiving device can be divided into multiple cases, and the following description is given respectively.

Receiving channel 1: the receiving device is a single-channel receiving device.

Specifically, the receiving device receives one function value sent by the sending device and the at least one sending parameter value used for obtaining the function value through a single channel; the receiving device brings the received one function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value.

The receiving device receives the x value and the f (x) value sent by the sending device, and then brings the received x value and f (x) value into the polynomial function:

f(x)＝a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function equation 1

Thus, the key parameter a is calculated ₀ Is a value of (2).

Receiving channel 2: the receiving device is a multi-channel receiver.

Specifically, for any channel, the receiving device receives, through the channel, a function value sent by the sending device and the at least one sending parameter value used for obtaining the function value; the receiving device brings the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value, and the method comprises the following steps: the receiving device brings at least one function value received by the same quantum channel and the at least one sending parameter value into a corresponding polynomial function to obtain a key parameter value.

Assuming that the polynomial function for quantum key distribution set by the transmitting device and the receiving device is unique, f (x) =a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function, where the receiving device knows the parameter a ₁ 、a ₂ 、…a _t-1 P.

The transmitting device transmits (f (x 1), (f (x 2), x 2) … (f (xn), xn) to the receiving device through n quantum channels, respectively, which, upon receiving (f (x 1), (f (x 2), x 2) … (f (xn), xn), brings it into a polynomial function:

f(x)＝a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function equation 1

Thus, the corresponding key parameter value a is calculated ₀₁ …a _0n 。

The receiving device brings the received function value and the at least one sending parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value, and then the receiving device determines a quantum key according to the obtained key parameter value.

When the receiving device determines the quantum key according to the obtained key parameter values, the manner of determining the quantum key is different according to the different number of the obtained key parameter values, so that the quantum key can be divided into various cases, and the description is respectively carried out below.

Determination mode 1: and if the key parameter values obtained by the receiving equipment are a plurality of, the receiving equipment synthesizes the plurality of key parameter values to obtain the quantum key.

f(x)＝a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function equation 1

Then, the corresponding key parameter value a is calculated ₀₁ …a _0n Finally, the receiving device may implement the session key Ks based on the hash function g with strong security, i.e.: ks=g (a ₀₁ 、a ₀₂ 、…a _0n )。

It should be noted that, here, g may be a hash function with strong security, such as SHA (Secure Hash Algorithm ) -256, SHA-512, SHA-3, OR may be other operation functions, such as XOR (exclusive OR), etc., any function that can be applied to the key synthesis of the present invention falls within the scope of the present invention, where the algorithm function used for the synthesis is determined according to the protocol content of the receiving device and the transmitting device.

When the receiving device receives through the quantum channel, the channel is suddenly changed in state once an attack or an intrusion is performed on a certain channel in the quantum communication process, so that communication is blocked. Therefore, in the embodiment of the invention, in order to obtain the accurate key, the attacked channel is eliminated when the quantum key is synthesized.

Specifically, if the receiving device determines that some quantum channels in the quantum channels that receive the quantum keys are interfered, the receiving device synthesizes the key parameter values obtained by the function values and the transmission parameter values received by the quantum channels that are not interfered into the quantum keys.

For example, after receiving (f (x 1), x 1), (f (x 2), x 2) … (f (xn), the receiving device determines that the received (f (x 1), x 1) is received through the attacked channel, and deletes the received (f (x 1), x 1), and then brings the remaining (f (x 2), x 2) … (f (xn), xn) into the polynomial function:

f(x)＝a ₀ +a ₁ x+…+a _t-1 x ^t-1 mod p polynomial function equation 1

Then, the corresponding key parameter value a is calculated ₀₂ …a _0n Finally, the receiving device may implement the session key Ks based on the hash function g with strong security, i.e.: ks=g (a ₀₁ 、a ₀₂ 、…a _0n )。

Determination mode 2: and if the key parameter values obtained by the receiving equipment are 1, the receiving equipment determines the key parameter values as quantum keys.

In some possible implementations, aspects of the method for quantum key distribution provided by the embodiments of the present invention may also be implemented in the form of a program product including program code for causing a computer device to perform the steps of the method for quantum key distribution according to the various exemplary embodiments of the present invention as described in this specification, when the program code is run on the computer device.

The program product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

A program product for data forwarding control according to an embodiment of the present invention may employ a portable compact disc read only memory (CD-ROM) and include program code and may run on a server device. However, the program product of the present invention is not limited thereto, and in this document, a readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an information transmission, apparatus, or device.

The readable signal medium may include a data signal propagated in baseband or as part of a carrier wave with readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. The readable signal medium may also be any readable medium that is not a readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with a periodic network action system, apparatus, or device.

Program code embodied on a readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device.

As shown in fig. 8, an embodiment of the present invention provides a device for quantum key distribution, including: processor 800 and transceiver 801:

the processor 800 is configured to bring, via the transceiver 801, a key parameter value for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain a function value; and transmitting the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value.

Optionally, the sending device is a single channel transmission, and the processor 800 is specifically configured to:

bringing the key parameter value and at least one transmission parameter value used for determining the quantum key into a polynomial function to obtain a function value; and transmitting the at least one transmission parameter value and the one function value to a receiving device through the single channel.

Optionally, the sending device is a multi-channel transmission, and the processor 800 is specifically configured to:

bringing the key parameter values for determining the quantum key and at least two transmission parameter values into a polynomial function to obtain at least two function values; and transmitting the at least one transmission parameter value and the at least one function value to the receiving device through each channel respectively.

Optionally, the processor 800 is specifically configured to:

bringing the key parameter value and at least one transmission parameter value used for determining the quantum key into a polynomial function to obtain a function value; and transmitting the at least one transmission parameter value and the one function value to the receiving device through each channel respectively.

Optionally, the processor 800 is specifically configured to:

obtaining a plurality of auxiliary parameter values according to the at least one sending parameter value and a plurality of preset parameter values; for any group of auxiliary parameter values, bringing the key parameter value used for determining the quantum key and the auxiliary parameter value into a polynomial function to obtain a function value, and transmitting the at least one transmission parameter value used for obtaining the function value and the auxiliary parameter value to the receiving device through a channel;

Wherein the function values transmitted by different channels are derived from different sets of auxiliary parameter values.

Optionally, the processor 800 is specifically configured to:

determining a plurality of sets of transmission parameter values; for any group of transmission parameter values, carrying the key parameter value for determining the quantum key and the transmission parameter value into a polynomial function to obtain a function value, and transmitting the obtained function value and the at least one transmission parameter value used for obtaining the function value to the receiving device through a channel;

wherein the function values for different channel transmissions are derived from different sets of transmission parameter values.

Alternatively, the polynomial functions carried in by the different groups are the same.

Optionally, the processor 800 is specifically configured to:

and transmitting the at least one transmission parameter value and the function value to receiving equipment through a relay station.

As shown in fig. 9, the present invention provides a quantum key distribution apparatus, the apparatus comprising:

at least one processing unit 900 and at least one storage unit 901, wherein the storage unit stores program code which, when executed by the processing unit, causes the processing unit to perform the following process:

The method comprises the steps of carrying key parameter values for determining a quantum key and at least one sending parameter value into a polynomial function to obtain a function value; and transmitting the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value.

Optionally, the sending device is a single channel transmission, and the processing unit 900 is specifically configured to:

Optionally, the sending device is a multi-channel transmission, and the processing unit 900 is specifically configured to:

Optionally, the processing unit 900 is specifically configured to:

As shown in fig. 10, an embodiment of the present invention provides a quantum key distribution apparatus, including: processor 1000 and transceiver 1001:

the processor 1000: at least one function value for receiving a transmission device transmission through the transceiver 1001 and obtaining the at least one transmission parameter value used by the function value; bringing the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; and determining a quantum key according to the obtained key parameter value.

Optionally, the receiving device is a single channel receiving device, and the processor 1000 is specifically configured to:

receiving one function value transmitted by the transmitting device through a single channel, and obtaining the at least one transmission parameter value used by the function value; and carrying the received one function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value.

Optionally, the receiving device is multi-channel receiving, and the processor 1000 is specifically configured to:

for any channel, receiving a function value sent by the sending device and obtaining the at least one sending parameter value used by the function value through the channel; and bringing at least one function value received by the same quantum channel and the at least one sending parameter value into a corresponding polynomial function to obtain a key parameter value.

Optionally, the processor 1000 is specifically configured to:

if the key parameter values obtained by the receiving equipment are a plurality of, synthesizing the obtained key parameter values to obtain a quantum key; or alternatively, the first and second heat exchangers may be,

and if the key parameter values obtained by the receiving equipment are 1, determining the key parameter values as quantum keys.

Optionally, the processor 1000 is further configured to:

if it is determined that some of the quantum channels are interfered, a quantum key is synthesized from key parameter values obtained from the function values and transmission parameter values received through the quantum channels not interfered.

As shown in fig. 11, the present invention provides a quantum key distribution apparatus comprising:

At least one processing unit 1100 and at least one storage unit 1101, wherein the storage unit stores program code that, when executed by the processing unit, causes the processing unit to perform the following process:

at least one function value for transmission by a transmitting device via a transceiver and the at least one transmission parameter value for use in deriving the function value; bringing the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; and determining a quantum key according to the obtained key parameter value.

Optionally, the receiving device is a single channel receiving, and the processing unit 1100 is specifically configured to:

Optionally, the receiving device is multi-channel receiving, and the processing unit 1100 is specifically configured to:

Optionally, the processing unit 1100 is specifically configured to:

Optionally, the processing unit 1100 is further configured to:

Embodiments of the present invention also provide a non-transitory readable storage medium comprising program code for causing a computing device to perform the steps of the method of quantum key distribution when the program code is run on the computing device.

Based on the same inventive concept, the embodiment of the invention also provides a quantum key distribution method, and because the device corresponding to the method is the quantum key distribution device of the embodiment of the invention, and the principle of solving the problem of the method is similar to that of the device, the implementation of the method can refer to the implementation of a system, and the repetition is omitted.

As shown in fig. 12, the method for distributing quantum keys provided by the embodiment of the invention specifically includes the following steps:

step 1200, the sending device brings key parameter values for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value;

step 1201, the transmitting device transmits the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value.

Optionally, the sending device is a single channel transmission;

the transmitting device brings key parameter values for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain a function value, comprising:

the sending device brings key parameter values for determining the quantum key and at least one sending parameter value into a polynomial function to obtain a function value;

the transmitting device transmitting the at least one transmission parameter value and the function value to a receiving device, including:

the transmitting device transmits the at least one transmission parameter value and the one function value to the receiving device through the single channel.

Optionally, the sending device is a multi-channel transmission;

the sending equipment brings key parameter values for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values;

the transmitting device transmits the at least one transmission parameter value and the at least one function value to the receiving device through each channel, respectively.

Optionally, the sending device brings the key parameter value for determining the quantum key and at least two sending parameter values into a polynomial function to obtain at least two function values, including:

the transmitting device brings the key parameter value and at least one transmission parameter value used for determining the quantum key into a polynomial function to obtain a function value;

the transmitting device transmitting the at least one transmission parameter value and the at least one function value to the receiving device through each channel, respectively, includes:

The transmitting device transmits the at least one transmission parameter value and the one function value to the receiving device through each channel, respectively.

Optionally, the sending device brings the key parameter value for determining the quantum key and the at least one sending parameter value into a polynomial function to obtain at least one function value, including:

the sending equipment obtains a plurality of groups of auxiliary parameter values according to the at least one sending parameter value and a plurality of groups of preset parameter values;

for any group of auxiliary parameter values, the sending device brings the key parameter value for determining the quantum key and the auxiliary parameter value into a polynomial function to obtain a function value, and sends the at least one sending parameter value used for obtaining the function value and the auxiliary parameter value to the receiving device through a channel;

the transmitting device determining a plurality of sets of transmission parameter values;

For any group of transmission parameter values, the transmission device brings the key parameter value for determining the quantum key and the transmission parameter value into a polynomial function to obtain a function value, and transmits the obtained function value and the at least one transmission parameter value used for obtaining the function value to the receiving device through a channel;

Alternatively, the same set of polynomial functions are brought in.

Optionally, the transmitting device transmits the at least one transmission parameter value and the function value to a receiving device, including:

the transmitting device transmits the at least one transmission parameter value and the function value to the receiving device through the relay station.

As shown in fig. 13, an embodiment of the present invention further provides a method for quantum key distribution, where the method includes:

Step 1300, a receiving device receives at least one function value sent by a sending device and obtains the at least one sending parameter value used by the function value;

step 1301, the receiving device brings the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value.

Step 1302, the receiving device determines a quantum key according to the obtained key parameter value.

Optionally, the receiving device is a single-channel receiving device;

the receiving device receiving at least one function value sent by a sending device and obtaining the at least one sending parameter value used by the function value includes:

the receiving device receives one function value sent by the sending device through a single channel and obtains the at least one sending parameter value used by the function value;

the receiving device brings the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value, and the method comprises the following steps:

the receiving device brings the received one function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value.

Optionally, the receiving device is a multi-channel receiving device;

the receiving device receiving at least two function values sent by a sending device and obtaining the at least two sending parameter values used by the function values includes:

for any channel, the receiving device receives a function value sent by the sending device and the at least one sending parameter value used for obtaining the function value through the channel;

the receiving device brings at least one function value received by the same quantum channel and the at least one sending parameter value into a corresponding polynomial function to obtain a key parameter value.

Optionally, the receiving device determines a quantum key according to the obtained key parameter value, including:

if the key parameter values obtained by the receiving equipment are a plurality of, the receiving equipment synthesizes the obtained key parameter values to obtain a quantum key; or alternatively, the first and second heat exchangers may be,

Optionally, if the key parameter value obtained by the receiving device is multiple, the receiving device synthesizes the multiple obtained key parameter values to obtain the quantum key, and further includes:

if the receiving device determines that some quantum channels in the quantum channels for receiving are interfered, the receiving device synthesizes the key parameter values obtained through the function values and the sending parameter values received by the quantum channels without being interfered into a quantum key.

In the embodiments provided in the present application, the method provided in the embodiments of the present application is described from the perspective that the transmitting device and the receiving device are the execution subjects. In order to implement the functions in the methods provided in the embodiments of the present application, the transmitting device and the receiving device may include hardware structures and/or software modules, and implement the functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Some of the functions described above are performed in a hardware configuration, a software module, or a combination of hardware and software modules, depending on the specific application of the solution and design constraints.

As shown in fig. 14, the method for quantum key distribution provided by the embodiment of the present invention is introduced by selecting a case of transmission through multiple channels, and specifically includes the following steps:

Step 1400, the transmitting device determines a key parameter value of the quantum key;

step 1401, the transmitting device brings the key parameter value for determining the quantum key and at least two transmission parameter values into a polynomial function to obtain a corresponding function value respectively;

step 1402, the sending device sends the at least two sending parameter values and the function value to a receiving device;

step 1403, the receiving device determines whether the channel receiving the channel is attacked, if yes, step 1404 is executed, and if not, step 1405 is executed;

step 1404, the receiving device discarding at least one transmission parameter value received through the attacked channel and the function value;

step 1405, the receiving device brings the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value;

step 1406, the receiving device brings the function value received by the channel not under attack and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value;

step 1407, the receiving device determines whether the number of obtained key parameter values is one, if yes, step 1408 is executed, and if not, step 1409 is executed;

Step 1408, if the key parameter values obtained by the receiving device are 1, the receiving device determines the key parameter values as a quantum key;

step 1409, if the key parameter values obtained by the receiving device are multiple, the receiving device synthesizes the multiple obtained key parameter values to obtain a quantum key;

the present application is described above with reference to block diagrams and/or flowchart illustrations of methods, apparatus (systems) and/or computer program products according to embodiments of the application. It will be understood that one block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, and/or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

Accordingly, the present application may also be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). Still further, the present application may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. In the context of this application, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A method of quantum key distribution, the method comprising:

the sending device brings key parameter values for determining the quantum key and at least one sending parameter value into a polynomial function to obtain at least one function value;

the transmitting device transmits the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value;

if the sending device is multi-channel transmission, the sending device brings a key parameter value for determining a quantum key and at least one sending parameter value into a polynomial function to obtain a function value, including:

2. The method of claim 1, wherein if the transmitting device is a single channel transmission, the transmitting device brings key parameter values for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain a function value, comprising:

3. The method of claim 1, wherein the transmitting device brings key parameter values for determining the quantum key and at least two transmission parameter values into a polynomial function to obtain at least two function values, comprising:

the transmitting device transmits the at least one transmission parameter value and a function value corresponding to the at least one transmission parameter value to the receiving device through each channel respectively.

4. The method of claim 1, wherein the transmitting device brings key parameter values for determining the quantum key and at least one transmission parameter value into a polynomial function to obtain at least one function value, comprising:

5. The method of claim 4, wherein the polynomial functions carried in by different sets are the same.

6. The method according to any one of claims 1 to 4, wherein the transmitting device transmitting the at least one transmission parameter value and the function value to a receiving device, comprises:

7. A method of quantum key distribution, the method comprising:

the receiving equipment receives at least one function value sent by the sending equipment and obtains the at least one sending parameter value used by the function value;

the receiving equipment brings the received function value and the at least one sending parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value;

the receiving equipment determines a quantum key according to the obtained key parameter value;

if the receiving device is a multi-channel receiving device, the receiving device receives at least two function values sent by the sending device and obtains the at least two sending parameter values used by the function values, and the method includes:

8. The method of claim 7, wherein if the receiving device is single channel receiving, the receiving device receiving at least one function value sent by a sending device and obtaining the at least one sending parameter value used by the function value comprises:

9. The method according to claim 7 or 8, wherein the receiving device determining a quantum key from the obtained key parameter value comprises:

if the key parameter values obtained by the receiving equipment are a plurality of, the receiving equipment synthesizes the obtained key parameter values to obtain a quantum key; or (b)

10. The method of claim 9, wherein if the key parameter values obtained by the receiving device are plural, the receiving device performs a synthesis process on the plural obtained key parameter values to obtain the quantum key, and further comprising:

11. A device for quantum key distribution applied to a transmitting device, characterized in that the device for quantum key distribution comprises: processor and transceiver:

the processor is used for bringing the key parameter value for determining the quantum key and at least one transmission parameter value into a polynomial function through the transceiver to obtain a function value; transmitting the at least one transmission parameter value and the function value to a receiving device, so that the receiving device obtains the quantum key according to the key parameter value determined by the at least one transmission parameter value and the function value;

if the sending device is multi-channel transmission, the processor is specifically configured to:

12. The apparatus of claim 11, wherein if the transmitting apparatus is a single channel transmission, the processor is specifically configured to:

13. The apparatus of claim 11, wherein the processor is specifically configured to:

14. The apparatus of claim 11, wherein the processor is specifically configured to:

15. The apparatus of claim 14, wherein the polynomial functions carried in by different sets are the same.

16. The apparatus according to any one of claims 11 to 14, wherein the processor is specifically configured to:

17. A device for quantum key distribution applied to a receiving device, the device comprising: processor and transceiver:

the processor is configured to receive, through a transceiver, at least one function value sent by a sending device and obtain the at least one sending parameter value used by the function value; bringing the received function value and the at least one transmission parameter value used for obtaining the function value into a polynomial function to obtain a key parameter value; determining a quantum key according to the obtained key parameter value;

if the receiving device is a multi-channel receiving device, the processor is specifically configured to:

18. The apparatus of claim 17, wherein the receiving apparatus is a single channel receiver, the processor being specifically configured to:

19. The apparatus of claim 17 or 18, wherein the processor is specifically configured to:

if the key parameter values obtained by the receiving equipment are a plurality of, synthesizing the obtained key parameter values to obtain a quantum key; or (b)

20. The apparatus of claim 17 or 18, wherein the processor is further configured to:

21. A device for quantum key distribution, the device comprising: at least one processing unit and at least one storage unit, wherein the storage unit stores program code which, when executed by the processing unit, causes the processing unit to perform the steps of the method of any one of claims 1 to 6 or the steps of the method of any one of claims 7 to 10.

22. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6 or the steps of the method according to any one of claims 7 to 10.