A counterfactual quantum certificate authorization system and method

Abstract

The invention discloses a counterfactual quantum certificate authorization system and method, which relate to the field of quantum communication technology. The system comprises: a client, a bank and an authorization center; the authorization center comprises: a single photon source, a circulator, a first beam splitter, a second beam splitter, a first optical delay coil, a first Faraday mirror, a switchable reflector, a first detector and a second detector; the client comprises: a second optical delay coil, a first optical switch, a second Faraday mirror and a third detector; the bank comprises: a third optical delay coil, a second optical switch, a third Faraday mirror and a fourth detector; after the single photon source sends a single photon, the client and the bank randomly control the opening and closing of the first optical switch and the second optical switch for encoding, and only when the second detector has response information, the encoding of the client and the bank is the same, and since the photon detected by the second detector does not appear in the channel between the client and the bank, the process achieves the purpose of counterfactual communication.

Description

Technical Field

[0001] The present invention relates to the field of quantum communication technology, and in particular to a counterfactual quantum certificate authorization system and method. Background Art

[0002] With the popularization of the Internet, e-commerce has gradually integrated into people's lives. As a new transaction model, it plays an increasingly important role in the operation of enterprises, markets and even national economies. The security technology of e-commerce is a key technology that affects the development of e-commerce. CA authentication technology based on basic encryption algorithms is the core of e-commerce security. In the classic certificate authorization, the authorization center Charlie sends a digital certificate containing the authentication public key and identity information to the customer Alice and the bank Bob. Assuming that Alice wants to conduct a transaction with Bob, Bob needs to send his digital certificate to Alice. After verifying Bob's identity with Charlie, Alice uses the public key in the certificate to encrypt the information to be transmitted. After receiving the encrypted information, Bob uses the private key corresponding to the public key in the certificate to decrypt the certificate, so that Alice and Bob have completed a transaction.

[0003] Counterfactual quantum cryptography uses interaction-free measurement and the quantum Zeno effect to achieve secret information transmission without energy exchange or particle transmission. In 1993, based on the equal-arm Mach-Zehnder interferometer, Elitzur and Vaidman detected the existence of a bomb without detonating it. In 1995, Kwait et al. designed a chained Mach-Zehnder interferometer based on the quantum Zeno effect. When an obstacle exists, no physical particles appear in the transmission channel. In 2013, Salih et al. further improved the above scheme by nesting the chained MZI in one arm of the chained MZI. In this protocol, no physical particles will appear in the transmission channel for the transmission of two logical bits, thus realizing "direct counterfactual quantum communication". In 2019, Aharonov et al. designed a double-nested Mach-Zehnder interferometer, proving in physical theory and logic that two bits of information can indeed be transmitted without exchanging physical particles. In 2014, Indian scholars applied counterfactual quantum key distribution to certificate authorization in e-commerce. In a Michelson interferometer, the certificate authority Charlie emits a single photon into the interferometer, and Alice and Bob randomly choose to absorb or reflect photons at both ends of the interferometer for encoding. Although in this scheme, there is no particle transmission between Alice and Bob, every time a key bit is generated, there must be a particle transmission between one of them and Charlie, and the security of the protocol will be affected. Summary of the invention

[0004] The purpose of the present invention is to provide a counterfactual quantum certificate authorization system and method, which can solve the problem of particle transmission between the client, bank and authorization center in the process of generating key bits, and realize complete counterfactual quantum certificate authorization.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A counterfactual quantum certificate authorization system, the system comprising: a client, a bank, and an authorization center; the client and the bank are optically connected to the authorization center respectively;

[0007] The authorization center end includes: a single photon source, a circulator, a first beam splitter, a second beam splitter, a first optical delay coil, a first Faraday mirror, a switchable reflector, and a first detector and a second detector; wherein, the single photon source exit port is connected to the first port of the circulator, the second port of the circulator is connected to the first port of the first beam splitter, the third port of the circulator is connected to the first detector, the third port of the first beam splitter is connected to the first port of the first optical delay coil, the second port of the first optical delay coil is connected to the first Faraday mirror, the fourth port of the first beam splitter is connected to the second detector, the second port of the first beam splitter is connected to the first port of the switchable reflector, the second port of the switchable reflector is connected to the first port of the second beam splitter, the third port of the second beam splitter is connected to the communication channel c leading to the client, and the fourth port of the second beam splitter is connected to the communication channel d leading to the bank end;

[0008] The client comprises: a second optical delay coil, a first optical switch, a second Faraday mirror, and a third detector; wherein the client communication channel c is connected to the first port of the second optical delay coil, the second port of the second optical delay coil is connected to the first port of the first optical switch, the third port of the first optical switch is connected to the second Faraday mirror, and the second port of the first optical switch is connected to the third detector;

[0009] The bank end includes: a third optical delay coil, a second optical switch, a third Faraday mirror, and a fourth detector; wherein the bank end communication channel d is connected to the first port of the third optical delay coil, the second port of the third optical delay coil is connected to the first port of the second optical switch, the third port of the second optical switch is connected to the third Faraday mirror, and the second port of the second optical switch is connected to the fourth detector;

[0010] The client end and the bank end are optically connected to the authorization center end through nested Michelson interferometers respectively;

[0011] The authorization center uses a switchable reflector to fold the optical path to control the number of times the optical pulse passes through the client and the bank;

[0012] The authorization center turns on the switchable reflector to make the light pulse pass through the client and the bank twice, forming a double nested structure, eliminating the trajectory information of the photon in the channel, and realizing counterfactual quantum certificate authorization;

[0013] The authorization center turns off the switchable reflector, allowing the light pulse to pass through the client and the bank once, forming a single nested structure, and obtains the security key after data post-processing. Finally, the encoded photon is still counterfactual;

[0014] The switchable reflector is realized by a Sagnac ring interferometer composed of a phase modulator and a third beam splitter; the two paths of the Sagnac ring interferometer correspond to the two ports of the switchable reflector respectively, and the opening and closing of the switchable reflector is controlled by adjusting the phase modulator, thereby controlling the number of times the light pulse enters the client end and the bank end.

[0015] Optionally, the incident transmission-reflection ratio at the first port of the first beam splitter is 4:1; the incident transmission-reflection ratio at the third port of the first beam splitter is 1:4; and the transmission-reflection ratio of the second beam splitter is 1:1.

[0016] Optionally, the client and the bank perform identity authentication by means of the fully counterfactual communication.

[0017] Optionally, the client and the bank distribute keys by means of the completely counterfactual communication.

[0018] The present invention also provides a counterfactual quantum certificate authorization method based on the above counterfactual quantum certificate authorization system, the method comprising:

[0019] A single photon source at the authorization center is used to send a single photon; after the single photon enters the interferometer, it is divided into two pulses, one entering the external interferometer and the other entering the internal interferometer. The client and the bank are connected through the internal interferometer; the client and the bank are respectively placed at the two ends of the internal interferometer; there are two ways to connect the external interferometer and the internal interferometer, including: using a double-nested structure interferometer to make the light pulse enter the internal interferometer twice, which can eliminate the trajectory information of the photon in the channel and realize the counterfactual quantum certificate authorization; using a single-nested structure interferometer to make the light pulse enter the internal interferometer once, and after data post-processing, the security key can be obtained, and the final encoded photon is also counterfactual.

[0020] When the optical pulse enters the client after being split, the opening and closing of the first optical switch is randomly controlled, and client coding is performed;

[0021] When the optical pulse enters the bank end after beam splitting, the opening and closing of the second optical switch is randomly controlled, and bank end coding is performed;

[0022] The authorization center obtains responses from the first detector and the second detector. When the first detector responds, no coding information is obtained; when the second detector responds, it is determined that the coding of the client and the bank is the same.

[0023] Optionally, the client encoding method is: when the first optical switch is turned on, the optical path is blocked, and the encoding is 0; when the first optical switch is turned off, the optical path is connected, and the encoding is 1;

[0024] The bank-side coding method is: when the second optical switch is turned on, the optical path is blocked and the coding is 0; when the second optical switch is turned off, the optical path is connected and the coding is 1.

[0025] Optionally, the client and the bank achieve correlation between physical systems by measuring quantum states, thereby sharing keys.

[0026] It is applied to a counterfactual quantum certificate authorization system, the system includes a client, a bank, and an authorization center; the client and the bank are optically connected to the authorization center respectively, and the method includes:

[0027] The optical path includes a single photon source, an external interferometer and an internal interferometer. The authorization center emits a single photon which enters the interferometer and is then divided into two pulses, one entering the external interferometer and the other entering the internal interferometer. The client and the bank are connected via the internal interferometer.

[0028] The client and the bank are respectively placed at two ends of the internal interferometer to receive and control whether the encoding is bit 0 or bit 1;

[0029] Optionally, the encoding method of the client and the bank is: when the light path is on, the encoding is 0, and when the light path is blocked, the encoding is 1;

[0030] There are two ways to connect the external interferometer and the internal interferometer, including:

[0031] By using the double nested structure interferometer to allow the light pulse to enter the internal interferometer twice, the trajectory information of the photon in the channel can be eliminated, thereby realizing the counterfactual quantum certificate authorization;

[0032] The single nested structure interferometer is used to make the light pulse enter the internal interferometer once, and the security key can be obtained after data post-processing, and the final encoded photon is also counterfactual;

[0033] When the authorization center obtains the counterfactual detection, the communicating parties can know whether each other's coded bit is 0 or 1 according to the response;

[0034] The method does not need to use a public key to authenticate the client and the bank, and simultaneously implements identity authentication and key distribution;

[0035] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0036] Since the detection result of the authorization center is not used as the final key bit during the communication process of the present invention, the client and the bank can achieve the association between the physical systems by measuring the quantum state, thereby sharing the key, so the present invention improves the security of the scheme. Since the client and the bank can know that the other party's encoding is the same as their own encoding through the result of counterfactual detection, and the last detected photon does not appear in the channel between the authorization center and the client (bank), the present invention solves the problem of particle transmission between the authorization center end and the client end (bank end) during the process of generating key bits, and realizes complete counterfactual quantum certificate authorization. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A schematic diagram of the structure of a counterfactual quantum certificate authorization system provided in Example 1 of the present invention.

[0039] Figure 2 A schematic structural diagram of a switchable reflector provided in Example 1 of the present invention.

[0040] Figure 3-4 A schematic diagram of photon path information under different encoding conditions provided in Example 2 of the present invention.

[0041] Figure 5 This is the trajectory information of photons under the binary vector theory provided by Example 2 of the present invention.

[0042] Figure 6-7 A schematic diagram of photon path information under different encoding conditions after simplifying a double nested structure into a single nested structure provided in Embodiment 2 of the present invention.

[0043] Explanation of symbols:

[0044] Single photon source—101, circulator—102, first beam splitter—103, second beam splitter—109, first optical delay coil—106, first Faraday mirror—107, switchable reflector—108, first detector—104, second detector—105, second optical delay coil—110, first optical switch—111, second Faraday mirror—112, third detector—113, third optical delay coil—114, second optical switch—115, third Faraday mirror—116, fourth detector—117. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The purpose of the present invention is to propose a counterfactual quantum certificate authorization system and method. The semi-trusted authorization center (Charlie) uses a Michelson interferometer to connect the client (Alice) end and the bank (Bob) end to help users complete identity authentication and distribute keys. Charlie prepares an arbitrary quantum state, and Alice and Bob use optical switches at both ends of the interferometer to manipulate the quantum state. Finally, the detection results published by Charlie are used to associate the classical bits of the two. At the same time, identity authentication and key distribution without particle exchange between Alice (Bob) and Charlie are realized, and the security of the scheme is improved.

[0047] The purpose of the present invention is to provide a counterfactual quantum certificate authorization system and method, which can solve the problem of particle transmission between the bank end and the client end in the process of generating key bits, and realize complete counterfactual quantum certificate authorization.

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] like Figure 1 As shown, this embodiment provides a counterfactual quantum certificate authorization system, the system includes: a client, a bank and an authorization center; the client and the bank are optically connected to the authorization center respectively; the client and the bank are optically connected to the authorization center via a Michelson interferometer.

[0051] The authorization center end includes: a single photon source 101, a circulator 102, a first beam splitter 103, a second beam splitter 109, a first optical delay coil 106, a first Faraday mirror 107, a switchable reflector 108, a first detector 104, and a second detector 105; wherein the output port of the single photon source 101 is connected to the first port of the circulator 102, the second port of the circulator 102 is connected to the first port of the first beam splitter 103, the third port of the circulator 102 is connected to the first detector 104, and the third port of the first beam splitter 103 is connected to the first detector 104. The first port of the first optical delay coil 106 is connected to the first port, the second port of the first optical delay coil 106 is connected to the first Faraday mirror 107, the fourth port of the first beam splitter 103 is connected to the second detector 105, the second port of the first beam splitter 103 is connected to the first port of the switchable reflector 108, the second port of the switchable reflector 108 is connected to the first port of the second beam splitter 109, the third port of the second beam splitter 109 is connected to the communication channel c leading to the client, and the fourth port of the second beam splitter 109 is connected to the communication channel d leading to the bank end.

[0052] The client includes: a second optical delay coil 110, a first optical switch 111, a second Faraday mirror 112, and a third detector 113; wherein the client communication channel c is connected to the first port of the second optical delay coil 110, the second port of the second optical delay coil 110 is connected to the first port of the first optical switch 111, the third port of the first optical switch 111 is connected to the second Faraday mirror 112, and the second port of the first optical switch 111 is connected to the third detector 113.

[0053] The bank end includes: a third optical delay coil 114, a second optical switch 115, a third Faraday mirror 116, and a fourth detector 117; wherein, the bank communication channel d is connected to the first port of the third optical delay coil 114, the second port of the third optical delay coil 114 is connected to the first port of the second optical switch 115, the third port of the second optical switch 115 is connected to the third Faraday mirror 116, and the second port of the second optical switch 115 is connected to the fourth detector 117.

[0054] The incident transmission-reflection ratio at the first port of the first beam splitter is 4:1; the incident transmission-reflection ratio at the third port of the first beam splitter is 1:4; and the transmission-reflection ratio of the second beam splitter 109 is 1:1.

[0055] The switchable reflector 108 is implemented by a Sagnac ring interferometer composed of a phase modulator 201 and a beam splitter 202, as shown in FIG. Figure 2As shown, path 1 and path 2 of the Sagnac ring interferometer correspond to the first port and the second port of the switchable reflector 108, respectively. The switchable reflector 108 can be controlled by adjusting the phase modulator 201. The light pulse incident from path 1 is divided into two sub-pulses after passing through the beam splitter 202. When the phase is modulated to 0 by the phase modulator 201, the two sub-pulses interfere and finally emerge from path 2, corresponding to the switchable reflector 108 being closed; when the phase is modulated to π by the phase modulator 201, the emission direction of the pulse can be changed, and finally emerge from path 1, corresponding to the switchable reflector 108 being opened. The switchable reflector only eliminates the trajectory information.

[0056] The authorization center uses a switchable reflector to fold the optical path to control the number of times the optical pulse passes through the client and the bank.

[0057] The authorization center turns on the switchable reflector to make the light pulse pass through the client and the bank twice, forming a double nested structure, eliminating the trajectory information of the photon in the channel;

[0058] The authorization center turns off the switchable reflector to allow the light pulse to pass through the client and the bank once, forming a single nested structure. After data post-processing, the security key is obtained, and the final encoded photon is still counterfactual.

[0059] The client and the bank perform identity authentication and key distribution through completely counterfactual communication. Alice and Bob perform identity authentication and key distribution through a semi-trusted authorization center, without worrying about the authorization center delivering false messages for users.

[0060] Charlie prepares an arbitrary quantum state, and Alice and Bob use a set of classical basis pairs to encode the pulse. The encoded photons do not pass through Alice and Bob's encoders, and the authorization center cannot use the transmitted quantum state to steal the keys distributed between users. The use of quantum methods to complete certificate authorization in e-commerce has realized counterfactual quantum certificate authorization without particle transmission between Alice and Charlie, and between Bob and Charlie.

[0061] As an optional implementation, Charlie can turn on the switchable mirror to allow the light pulse to enter the same interferometer twice, eliminating the trajectory information of the photon in the channel; Charlie can turn off the switchable mirror to allow the light pulse to enter the interferometer once, and obtain the security key after data post-processing. Finally, the encoded photon is still counterfactual.

[0062] Charlie's detection result is not used as the final key bit. Alice and Bob can realize the association between physical systems by measuring the quantum state, thereby sharing the key and improving the security of the scheme.

[0063] First, the client sends a request to the certificate authority, then authenticates the bank with the help of the authority, and communication begins after the verification.

[0064] The single photon source 101 at the authorization center sends any quantum state |Ψ>, which enters the Michelson interferometer after passing through the circulator 102 (incident from the first port and emitted from the second port). In the interferometer, it is incident from the first port of the first beam splitter 103 and enters path a and path b when emitted. The quantum state can be expressed as:

[0065]

[0066] where |Ψ> input represents the incident quantum state, |Ψ> a |0> b Indicates that the photon passes through path a, |0> a |Ψ> b Indicates that the photon passes through path b.

[0067] The pulse of path a is emitted from the third port of the first beam splitter 103 and is reflected back to the first beam splitter 103 by the first Faraday mirror 107 after passing through the first optical delay coil 106. The pulse of path b is emitted from the 2nd port of the first beam splitter 103. At this time, the switchable reflector 108 is turned off. The pulse of path b is incident from the first port of the second beam splitter 109 after passing through the switchable reflector 108 and enters path c and path d respectively when emitted. At this time, the quantum state of path b |Ψ> b It can be expressed as:

[0068]

[0069] where |Ψ> b represents the quantum state incident from path b, |Ψ> c |0> d represents the photon passing through path c, |0> c |Ψ> d Indicates that the photon passes through path d.

[0070] Subsequently, the pulse of path c is emitted from the third port of the second beam splitter 109 and enters the client end, and the pulse of path d is emitted from the fourth port of the second beam splitter 109 and enters the bank end.

[0071] The client and bank end use the opening and closing of the first optical switch 111 and the second optical switch 115 to randomly absorb or reflect pulses for encoding: when the first optical switch 111 / the second optical switch 115 is turned on, the photon is absorbed by the third detector 113 / the fourth detector 117 and is encoded as 0; when the first optical switch 111 / the second optical switch 115 is turned off, the photon is reflected by the second Faraday mirror 112 / the third Faraday mirror 116 and is encoded as 1.

[0072] Among them, as a specific implementation method,

[0073] In the double nested structure quantum certificate authorization system:

[0074] After the two pulses are encoded by the first optical switch 111 / the second optical switch 115, four situations may occur, including:

[0075] If the customer code is 0 and the bank code is 1, the pulse of path c is absorbed by the third detector 113, the pulse of path d is reflected by the third Faraday mirror 116, and the reflected pulse is incident from the fourth port of the second beam splitter 109 and then split. One beam is emitted from the second port of 109, and the other beam is emitted from the first port of 109 and then passes through the switchable reflector 108 again. At this time, the switchable reflector 108 is turned on, and the reflected pulse is incident from the first port of the second beam splitter 109 again and then enters path c and path d again. The pulse of path c is emitted from the third port of the second beam splitter 109 and then enters the customer end, and the pulse of path d is emitted from the fourth port of the second beam splitter 109 and then enters the bank end. The pulse of path c is absorbed by the third detector 113, and the pulse of path d is reflected by the third Faraday mirror 116, and the reflected pulse is incident from the third port of the second beam splitter 109 and then split. One beam is emitted from the second port of the second beam splitter 109, and the other beam is emitted from the first port of the second beam splitter 109 and passes through the switchable reflector 108 for the third time. At this time, the switchable reflector 108 is turned off, so that the pulse passes normally and reaches the first beam splitter 103, interferes with the pulse of path a, and enters path e, triggering the response of the first detector 104. The quantum state can be expressed as:

[0076]

[0077] If the customer code is 1 and the bank code is 0, the pulse of path c is reflected by the third Faraday mirror 116, the pulse of path d is absorbed by the fourth detector 117, and the reflected pulse is incident from the third port of the second beam splitter 109 and then split. One beam is emitted from the second port of 109, and the other beam is emitted from the first port of 109 and then passes through the switchable reflector 108 again. At this time, the switchable reflector 108 is turned on, and the reflected pulse is incident from the first port of the second beam splitter 109 again and then splits into path c and path d again. The pulse of path c is emitted from the third port of the second beam splitter 109 and then enters the customer end, and the pulse of path d is emitted from the fourth port of the second beam splitter 109 and then enters the bank end. The pulse entering the bank end is absorbed by the fourth detector 117, and the pulse entering the customer end is reflected by the third Faraday mirror 116. The reflected pulse is incident from the third port of the second beam splitter 109 and then split. One beam is emitted from the second port of 109, and the other beam is emitted from the first port of 109 and passes through the switchable reflector 108 for the third time. At this time, the switchable reflector 108 is turned off, so that the pulse passes normally and reaches the first beam splitter 103, and enters the path e after interfering with the pulse a, triggering the first detector 104 to respond. The quantum state can be expressed as:

[0078]

[0079] If the customer code and bank code are both 1, the pulse of path c and the pulse of path d are reflected by the second Faraday mirror 112 and the third Faraday mirror 116 respectively, and the reflected pulses simultaneously reach the second beam splitter 109 to interfere, and finally exit from the second port of the second beam splitter 109. Subsequently, the returning pulse a is incident from the third port of the first beam splitter 103, the pulse exiting from the first port enters path e, triggering the first detector 104 to respond, and the pulse exiting from the fourth port enters path f, triggering the second detector 105 to respond. The quantum state can be expressed as:

[0080]

[0081] If the customer code and bank code are both 0, the pulse of path c and the pulse of path d are absorbed by the third detector 113 and the fourth detector 117 respectively. Then, the returning pulse a is incident from the third port of the first beam splitter 103, the pulse emitted from the first port enters the path e, triggering the first detector 104 to respond, and the pulse emitted from the fourth port enters the path f, triggering the second detector 105 to respond. The quantum state can be expressed as:

[0082]

[0083] where |Ψ> output represents the quantum state after emission, |Ψ> e |0> frepresents the photon emitted from path e, |0> e |Ψ> f The photon is emitted from path f.

[0084] In a quantum certificate authorization system with a single nested structure (simplifying the counterfactual quantum certificate authorization system with a double nested structure, keeping the switchable reflector 108 in the system always in a closed state):

[0085] After the two pulses are encoded by the first optical switch 111 / 115, four situations may occur, including:

[0086] If the customer code is 0 and the bank code is 1, pulse c is absorbed by the third detector 113, and pulse d is reflected by the third Faraday mirror 116. The reflected pulse is incident from the fourth port of the second beam splitter 109 and then split. One beam is emitted from the second port of the second beam splitter 109, and the other beam is emitted from the first port of the second beam splitter 109 and then reaches the first beam splitter 103, interfering with pulse a and triggering the first detector 104 to respond.

[0087] If the customer code is 1 and the bank code is 0, pulse c is reflected by the third Faraday mirror 116, and pulse d is absorbed by the fourth detector 117. The reflected pulse is incident from the third port of the second beam splitter 109 and then split into two beams, one of which is emitted from the second port of the second beam splitter 109, and the other is emitted from the first port of the second beam splitter 109 and reaches the first beam splitter 103, interfering with pulse a and triggering the first detector 104 to respond.

[0088] If the customer code and bank code are both 1, pulse c and pulse d are reflected by the second Faraday mirror 112 and the third Faraday mirror 116 respectively, and the reflected pulses simultaneously reach the second beam splitter 109 to interfere, and finally exit from the second port of the second beam splitter 109. At this time, the returned pulse a is incident from the third port of the first beam splitter 103, and the pulse exiting from the first port triggers the first detector 104 to respond, and the pulse exiting from the fourth port triggers the second detector 105 to respond.

[0089] If the customer code and bank code are both 0, pulse c and pulse d are respectively absorbed by the third detector 113 and the fourth detector 117. At this time, the returned pulse a is incident from the third port of the first beam splitter 103, the pulse emitted from the first port triggers the first detector 104 to respond, and the pulse emitted from the fourth port triggers the second detector 105 to respond.

[0090] Finally, the customer and the bank decide whether to keep or discard the operation based on the detector response published by the authorization center, including:

[0091] If the authorization center publishes the response of the first detector 104, the operation is discarded.

[0092] If the authorization center publishes the response of the second detector 105, the customer and the bank will know that the other party's code is the same as their own code.

[0093] Certificate authorization is a mechanism for conducting transactions through an authoritative CA certification agency. In this embodiment, the authorization center is responsible for both identity authentication and initiating communication in the quantum channel, completing the tasks of the e-commerce certificate authorization center.

[0094] For ease of understanding, this embodiment uses another easy-to-understand system to explain the principle of the above system:

[0095] A counterfactual quantum certificate authorization system includes a single photon source, an external interferometer and an internal interferometer. The client and the bank are connected through the internal interferometer. The client and the bank are respectively placed at the two ends of the internal interferometer to receive and control whether the encoding is bit 0 or bit 1. The connection method between the external interferometer and the internal interferometer is divided into a double nested structure and a single nested structure.

[0096] The double-nested structure interferometer contains a single photon source, an external interferometer, two internal interferometers and two detectors.

[0097] The external interferometer comprises a beam splitter 1, a beam splitter 6, a total reflector 1, a total reflector 2 and a double-sided mirror. The single-photon emitter is connected to the incident port of the beam splitter 1 of the external interferometer, the left end exit port of the beam splitter 1 is connected to the incident port of the total reflector 1, the exit port of the total reflector 1 is connected to the left end incident port of the double-sided mirror, the left end exit port of the double-sided mirror is connected to the incident port of the total reflector 2, the exit port of the total reflector 2 is connected to the left incident port of the beam splitter 6, and the left and right end exit ports of the beam splitter 6 are respectively connected to the detectors D1 and D0.

[0098] The first internal interferometer comprises beam splitter 2, beam splitter 3, total reflector 3, total reflector 4, optical switch 1 and optical switch 2. The right end exit port of beam splitter 1 of the external interferometer is connected to the incident port of beam splitter 2 of the first internal interferometer, and the left and right end exit ports of beam splitter 2 are connected to the incident ports of optical switch 1 and optical switch 2 respectively. The exit port of optical switch 1 is connected to the incident port of total reflector 3, the exit port of total reflector 3 is connected to the left end incident port of beam splitter 3, the exit port of optical switch 2 is connected to the incident port of total reflector 4, the exit port of total reflector 4 is connected to the right end incident port of beam splitter 3, and the left output port of beam splitter 3 is connected to the right incident port of the double-sided mirror.

[0099] The second internal interferometer comprises a beam splitter 4, a beam splitter 5, a total reflection mirror 5, a total reflection mirror 6, an optical switch 3 and an optical switch 4. The right end exit port of the double-sided mirror is connected to the incident port of the beam splitter 4 of the second internal interferometer, the left end and right end exit ports of the beam splitter 4 are respectively connected to the incident ports of the optical switch 3 and the optical switch 4, the exit port of the optical switch 3 is connected to the incident port of the total reflection mirror 5, the exit port of the total reflection mirror 5 is connected to the left end incident port of the beam splitter 5, the exit port of the optical switch 4 is connected to the incident port of the total reflection mirror 6, the exit port of the total reflection mirror 6 is connected to the right end incident port of the beam splitter 5, and the left output port of the beam splitter 5 is connected to the right end incident port of the beam splitter 6.

[0100] Among them, the transmission-reflection ratio of beam splitter 1 is 4:1, the transmission-reflection ratios of beam splitter 2, beam splitter 3, beam splitter 4, and beam splitter 5 are all 1:1, and the transmission-reflection ratio of beam splitter 6 is 1:4. Charlie first helps Alice and Bob verify each other's identities, and then prepares single photons to start communication. The single photons are divided into two light pulses after passing through beam splitter 1. Pulse 1 is reflected by total reflective mirror 1, double-sided mirror, and total reflective mirror 2 and reaches beam splitter 6. Pulse 2 enters the internal interferometer and is divided into two pulses after passing through beam splitter 2 and reaches Alice and Bob respectively. Alice and Bob use optical switches to randomly block or conduct the light path in the left and right arms of the internal interferometer to encode photons (when the optical switch is turned on, the light path is blocked, and the code is 0; when the optical switch is turned off, the light path is conducted, and the code is 1). Finally, Alice and Bob associate each other's coded information according to the response of the detector published by Charlie, thereby sharing the key.

[0101] The two-state vector theory believes that particles have two wave functions, forward and backward, and will leave traces on the path where the forward and backward wave functions overlap. Using the device diagram shown in this embodiment only leaves traces on the authorization center end (that is, only in the area where the forward and backward wave functions overlap in the external interferometer), and there are no traces on the client end and the bank end, achieving complete counterfactual communication.

[0102] To verify that this embodiment is completely counterfactual under the two-state vector theory, we use Figure 3 , Figure 4 The path information of photons is explained through Figure 5 represents the path that the photon actually takes. It should be noted that Figure 3-5 The nested MZI in is equivalent to the Michelson interferometer in Example 1.

[0103] The authorization center first helps the client and the bank to verify each other's identities, and then prepares single photons to start communication. The single photons are divided into two light pulses after passing through the first beam splitter. Pulse one is reflected by the total reflection mirror and the double-sided mirror and reaches the last beam splitter. Pulse two enters the internal interferometer and is divided into two pulses after passing through the beam splitter and reaches the client and the bank respectively. The client and the bank randomly block or open the light path in the left and right arms of the internal interferometer to encode the photons (light path blocked, coded as 0; light path open, coded as 1). Finally, the client and the bank associate each other's coding information according to the detector response published by the authorization center, thereby sharing the key (in short, through the response of the second detector, the client and the bank know that the codes of the two are the same. At this time, they can associate each other's coding information according to the detector response published by the authorization center, thereby sharing the key).

[0104] There are two situations in which the coded information can be obtained using the above method, including:

[0105] When the codes of the client and bank are both 1, the pulses entering the client and bank interfere in the first internal interferometer and eventually leave the interferometer. The pulses entering the external interferometer are split after passing through the last beam splitter, and eventually trigger the detector D0 / D1 to respond. The path information is as follows: Figure 3 shown.

[0106] When the codes of the client and bank are both 0, the pulses entering the client and bank are blocked. The pulses entering the external interferometer are split after passing through the last beam splitter, and finally trigger the detector D0 / D1 to respond. The path information is as follows Figure 4 shown.

[0107] After receiving the detector response, any receiver can know the sender's code based on its own code: if the detector D1 responds, no code information is obtained; if the detector D0 responds, it is known that the other party's code is the same as its own.

[0108] exist Figure 5 In the figure, the solid line is the possible path that the photon may take after being emitted, and the dotted line is the possible path that the photon may take before being received. The overlapping part of the solid and dotted lines shows the actual path that the photon takes. There is no trace of the photon appearing on the client side or the bank side, and the communication is completely counterfactual.

[0109] In addition, in this embodiment, the double nested structure can be simplified to a single nested structure, such as Figure 6 and Figure 7As shown. The external interferometer contains 2 beam splitters, 2 fully reflective mirrors and 2 detectors; the internal interferometer contains 2 beam splitters and 2 fully reflective mirrors. Compared with the double-nested MZ interferometer, the single-nested structure is simple to install and easy to operate. The light pulse only needs to enter the internal interferometer once for the client and the bank to complete the encoding, which is more advantageous in long-distance communication. For the single-nested structure, the two-state vector theory believes that when the internal interferometer is turned on, photons will leave traces in the internal interferometer, and the eavesdropper can extract information from these traces through weak measurement. However, this will affect the results of the interference to a certain extent, thereby introducing an error rate. In the actual operation process, we can quantify the amount of information of the eavesdropper based on the error rate, and subtract this part of the information during data post-processing. The final security key is still counterfactual.

[0110] The double nested interferometer allows the light pulse to enter the inner interferometer twice, which can eliminate the trajectory information of the photon in the channel and realize the counterfactual quantum certificate authorization;

[0111] The single nested structure interferometer allows the light pulse to enter the inner interferometer once, and after data post-processing, the security key can be obtained. The final encoded photon is also counterfactual;

[0112] The method of this embodiment does not require the use of public keys to authenticate the client and bank, and simultaneously implements identity authentication and key distribution;

[0113] During the whole process, photons do not appear in the communication channel between the client and the bank, and the communication is counterfactual;

[0114] During the communication process, the detection results of the authorization center are not used as the final key bits. The client and the bank realize the association between the physical systems through the measurement of quantum states, thereby sharing the key.

[0115] Compared with the prior art, this embodiment has the following beneficial effects:

[0116] Alice and Bob perform identity authentication and key distribution through a semi-trusted authorization center, without having to worry about the authorization center delivering false messages for the users.

[0117] This embodiment can achieve no particle transmission between Alice, Bob and Charlie, and realizes complete counterfactual quantum certificate authorization under the TSVF theory.

[0118] Charlie only needs to prepare a single quantum state, and Alice and Bob only use a set of classical basis pairs to encode the pulses, which simplifies the encoding device.

[0119] The encoded photons do not pass through Alice and Bob's encoders, and the authorized center cannot use the transmitted quantum state to steal the quantum keys distributed between users.

[0120] Charlie's detection result is not used as the final key bit. Alice and Bob can realize the association between physical systems by measuring the quantum state, thereby sharing the key and improving the security of the scheme.

[0121] Example 2

[0122] This embodiment provides a counterfactual quantum certificate authorization method, which is based on a counterfactual quantum certificate authorization system described in Embodiment 1, and includes:

[0123] Step S1: Use the single photon source at the authorization center to send a single photon; the single photon is divided into two pulses after entering the interferometer, one enters the external interferometer, and the other enters the internal interferometer. The client and the bank are connected through the internal interferometer; the client and the bank are respectively placed at the two ends of the internal interferometer.

[0124] Step S2: When the optical pulse enters the client after being split, the opening and closing of the first optical switch is randomly controlled, and client coding is performed; when the first optical switch is turned on, the optical path is blocked, and the coding is 0; when the first optical switch is turned off, the optical path is connected, and the coding is 1.

[0125] Step S3: When the optical pulse enters the bank end after beam splitting, the opening and closing of the second optical switch is randomly controlled, and the bank end coding is performed; when the second optical switch is turned on, the optical path is blocked and the coding is 0; when the second optical switch is turned off, the optical path is connected and the coding is 1.

[0126] Step S4: using the authorization center to obtain responses from the first detector and the second detector, when the first detector responds, no coding information is obtained; when the second detector responds, it is determined that the coding of the client and the bank is the same.

[0127] The client and the bank achieve the association between physical systems by measuring the quantum state, thereby sharing the key.

[0128] Those skilled in the art will appreciate that as long as the client and the bank know that the other party's code is the same as their own, coded communication can be performed.

[0129] It should be noted that the object information (including but not limited to object device information, object personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the present invention are all information and data authorized by the object or fully authorized by all parties, and the collection, use and processing of relevant data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0130] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided by the present invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided by the present invention may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited thereto. The processor involved in each embodiment provided by the present invention may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited thereto.

[0131] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0132] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A completely counterfactual quantum certificate authorization system, characterized in that: The system comprises: a client, a bank and an authorization center; the client and the bank are optically connected to the authorization center respectively; The authorization center end includes: a single photon source, a circulator, a first beam splitter, a second beam splitter, a first optical delay coil, a first Faraday mirror, a switchable reflector, and a first detector and a second detector; wherein, the single photon source exit port is connected to the first port of the circulator, the second port of the circulator is connected to the first port of the first beam splitter, the third port of the circulator is connected to the first detector, the third port of the first beam splitter is connected to the first port of the first optical delay coil, the second port of the first optical delay coil is connected to the first Faraday mirror, the fourth port of the first beam splitter is connected to the second detector, the second port of the first beam splitter is connected to the first port of the switchable reflector, the second port of the switchable reflector is connected to the first port of the second beam splitter, the third port of the second beam splitter is connected to the communication channel c leading to the client, and the fourth port of the second beam splitter is connected to the communication channel d leading to the bank end; The client comprises: a second optical delay coil, a first optical switch, a second Faraday mirror, and a third detector; wherein the client communication channel c is connected to the first port of the second optical delay coil, the second port of the second optical delay coil is connected to the first port of the first optical switch, the third port of the first optical switch is connected to the second Faraday mirror, and the second port of the first optical switch is connected to the third detector; The bank end includes: a third optical delay coil, a second optical switch, a third Faraday mirror, and a fourth detector; wherein the bank communication channel d is connected to the first port of the third optical delay coil, the second port of the third optical delay coil is connected to the first port of the second optical switch, the third port of the second optical switch is connected to the third Faraday mirror, and the second port of the second optical switch is connected to the fourth detector; The client end and the bank end are optically connected to the authorization center end through nested Michelson interferometers respectively; The authorization center uses a switchable reflector to fold the optical path to control the number of times the optical pulse passes through the client and the bank; The authorization center turns on the switchable reflector to make the light pulse pass through the client and the bank twice, forming a double nested structure, eliminating the trajectory information of the photon in the channel, and realizing counterfactual quantum certificate authorization; The authorization center turns off the switchable reflector, allowing the light pulse to pass through the client and the bank once, forming a single nested structure, and obtains the security key after data post-processing. Finally, the encoded photon is still counterfactual; The switchable reflector is realized by a Sagnac ring interferometer composed of a phase modulator and a third beam splitter; the two paths of the Sagnac ring interferometer correspond to the two ports of the switchable reflector respectively, and the opening and closing of the switchable reflector is controlled by adjusting the phase modulator, thereby controlling the number of times the light pulse enters the client end and the bank end.

2. A completely counterfactual quantum certificate authorization system according to claim 1, characterized in that: The incident transmission-reflection ratio at the first port of the first beam splitter is 4:1; the incident transmission-reflection ratio at the third port of the first beam splitter is 1:4, and the transmission-reflection ratio of the second beam splitter is 1:

1.

3. A completely counterfactual quantum certificate authorization system according to claim 1, characterized in that: The client and the bank perform identity authentication by means of the fully counterfactual communication.

4. A completely counterfactual quantum certificate authorization system according to claim 1, characterized in that: The client and the bank distribute keys by means of the completely counterfactual communication.

5. A completely counterfactual quantum certificate authorization method based on a completely counterfactual quantum certificate authorization system according to any one of claims 1 to 4, characterized in that: The method comprises: A single photon source at the authorization center is used to send a single photon; after the single photon enters the interferometer, it is divided into two pulses, one entering the external interferometer and the other entering the internal interferometer, and the client and the bank are connected through the internal interferometer; the client and the bank are respectively placed at the two ends of the internal interferometer; there are two ways to connect the external interferometer and the internal interferometer, including: using a double-nested structure interferometer to make the light pulse enter the internal interferometer twice, which can eliminate the trajectory information of the photon in the channel and realize the counterfactual quantum certificate authorization; using a single-nested structure interferometer to make the light pulse enter the internal interferometer once, and after data post-processing, the security key can be obtained, and the final encoded photon is also counterfactual; When the optical pulse enters the client after being split, the opening and closing of the first optical switch is randomly controlled, and client coding is performed; When the optical pulse enters the bank end after beam splitting, the opening and closing of the second optical switch is randomly controlled, and bank end coding is performed; The authorization center obtains responses from the first detector and the second detector. When the first detector responds, no coding information is obtained; when the second detector responds, it is determined that the coding of the client and the bank is the same.

6. A completely counterfactual quantum certificate authorization method according to claim 5, characterized in that: The client coding method is: when the first optical switch is turned on, the optical path is blocked, and the coding is 0; when the first optical switch is turned off, the optical path is connected, and the coding is 1; The bank-side coding method is: when the second optical switch is turned on, the optical path is blocked and the coding is 0; when the second optical switch is turned off, the optical path is connected and the coding is 1.

7. A completely counterfactual quantum certificate authorization method according to claim 5, characterized in that: The client and the bank achieve the association between the physical systems by measuring the quantum state, thereby sharing the key.

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