A strong blinding attack method in quantum secret sharing

Abstract

This invention discloses a high-intensity light blinding attack method for quantum secret sharing. Alice prepares N identical GHz states, divides them into three photon sequences, and transmits two photon sequences to Bob and Charlie respectively through two quantum channels. Eve blinds Bob's detector. When Alice sends photons to Bob, Eve intercepts the photons and, based on the measurement results, prepares a photon pulse with a power slightly greater than the detector's response power and sends it to Bob. Eve does not attack the photons Alice sends to Charlie. Then, the three parties implement the QSS procedure. If the light pulse signal emitted by Eve can cause a response at Bob's detector, Eve's measurement result is the same as Bob's measurement result, meaning Eve can obtain Bob's subkey. Finally, Eve can combine the subkey published by Charlie to obtain the key transmitted by Alice. This invention is simple to operate, easy to implement under current experimental conditions, does not increase the error rate of security detection, and is undetectable by the communicating parties, making it of significant application.

Description

Technical Field

[0001] This invention relates to a method for strong light blinding attack in quantum secret sharing, belonging to the technical field of quantum communication. Background Technology

[0002] Quantum secure communication aims to protect information security using the fundamental principles of quantum mechanics. Quantum communication possesses the ability to detect eavesdropping, a significant advantage over classical communication. Quantum secure communication encompasses numerous branches, such as quantum key distribution (QKD) and quantum secret sharing (QSS). QKD involves randomly generating a series of secure keys between the sender and receiver. QSS allows the key distributor to divide the complete key into multiple subkeys and distribute them to different users; only through cooperation among all users can the original complete key be reconstructed. Similar to other quantum secure communication schemes, while QSS theoretically possesses unconditional security, security vulnerabilities exist in QSS systems under imperfect experimental conditions, threatening the security of the key transmission process.

[0003] High-intensity blinding attacks are a type of quantum attack targeting practical, non-ideal single-photon detectors. Specifically, they involve injecting a high-intensity pulsed laser beam into the single-photon detector, switching its operating mode from Geiger mode to linear mode. This allows an eavesdropper to control the detector's response by adjusting the power of the input light pulse. High-intensity blinding attacks against QKD have been extensively studied. In 2010, the National University of Singapore, in collaboration with the Norwegian University of Science and Technology, first successfully demonstrated a probe-blinding attack on QKD. The results showed that through probe-blinding, Eve could completely steal the key without inducing any additional QBER. However, systematic research on probe-blinding attack methods for practical QSS systems is still lacking. This poses a security risk to the application of practical QSS systems under current imperfect experimental conditions. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the existing technology by proposing a strong light blinding attack method for quantum secret sharing. By combining it with intercept-retransmission attacks, the eavesdropper Eve can intercept the key without being detected by the communicating party. The attack only requires targeting one user terminal, is simple to operate, and can be implemented under current experimental conditions. This is of great significance for studying the security of practical QSS systems under imperfect experimental conditions.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for strong light blinding attack in quantum secret sharing, comprising the following steps:

[0006] Step 1: Alice, the key sender, prepares N pairs of identical 3-photon-GHZ states, and divides the corresponding photons of all GHZ states into 3 photon sequences S. A ,S B ,S C Each photon sequence contains N photons;

[0007] Step 2: Eve, the eavesdropper, uses a laser to generate a series of sufficiently bright laser pulses and injects them into Bob's photon detector. These laser pulses generate a large amount of photocurrent in a short period of time, thus blinding Bob's photon detector and causing it to operate in a linear mode. No attack is made on Charlie's detector.

[0008] Step 3: Alice will put S B ,S C The sequence of photons is transmitted to Bob and Charlie respectively through two quantum channels;

[0009] Step 4: During photon transmission, Eve intercepts some photons sent to Bob, randomly selects diagonal basis (X basis) and right-angle basis (Z basis) to measure the intercepted photons, and then prepares photon pulses with the same quantum state based on her measurement results. The power of the photon pulses is controlled to be greater than the response power of the detector at Bob's location, and sent to Bob through an ideal quantum channel. No interception is performed on the photons sent by Alice to Charlie.

[0010] Step 5: After photon transmission ends, Alice, Bob, and Charlie randomly select either Z-base or X-base to measure the photons in their hands and publish the measurement basis for each photon. If the three parties choose different bases, they discard the measurement results. If all three parties use X-base to measure the photons, Bob and Charlie retain their own measurement results as the original subkeys. If all three parties use Z-base to measure the photons, they publish the measurement results for security testing. After all photon measurements are completed, if the error rate of the security test does not exceed the set threshold, the security test passes, and the three parties consider the communication secure and proceed to the next step. If the error rate exceeds the set threshold, the three parties consider the communication insecure, and Bob and Charlie discard the generated subkeys, terminate the communication, and re-check the channel.

[0011] Step 6: For the photon intercepted by Eve, after Bob publishes the measurement basis, if both Eve and Bob choose the X basis for measurement, Eve's measurement result will be the same as Bob's, meaning Eve has obtained Bob's subkey. If both Eve and Bob choose the Z basis for measurement, Bob's measurement result will not cause a security detection error. If Eve and Bob choose different measurement bases, since Bob's photon detector is in linear mode, Bob's detector will not respond, and Bob will assume that the photon transmission has been lost. Therefore, because a blinding attack is performed on Bob's photon detector, Eve's intercept-retransmission attack will not increase the security detection error rate, allowing Eve to obtain part of Bob's subkey undetected.

[0012] Step 7: Alice, Bob, Charlie, and Eve repeat steps 1-6 above until Bob and Charlie obtain a sufficient number of subkeys;

[0013] Step 8: Through post-processing and privacy amplification, the three parties finally enable Bob and Charlie to obtain the secure subkey. Charlie then publishes his secure subkey. Bob, based on his own subkey and Charlie's subkey, finally deduces the key transmitted by Alice. Similarly, Eve, based on her own subkey and the subkey published by Charlie, also obtains part of the key transmitted by Alice.

[0014] Furthermore, the N pairs of identical GHZ states prepared by Alice in step 1 can be represented as:

[0015]

[0016] in, H Indicates horizontal polarization. V Indicates vertical polarization; subscripts A, B, and C indicate that the corresponding photons belong to three photon sequences S, respectively. A ,S B ,S C .

[0017] Furthermore, in step 2, the photon detector modes can be divided into linear mode and Geiger mode. Bob and Charlie's photon detectors were originally in Geiger mode, where the detectors only responded to single-photon signals. When Eve selected a suitable high-intensity pulsed laser and applied it to Bob's photon detector, Bob's photon detector entered linear mode. At this time, Bob's photon detector only responded to strong light signals, i.e., the power of the incident light pulse was stronger than the detector's response power and it did not respond to single-photon signals.

[0018] Furthermore, in steps 4 and 5, Alice, Bob, Charlie, and Eve each have two measurement basis choices, namely the X basis: { , }, Z-base: { , }, where the X basis is represented as .

[0019]

[0020] The measurement results for Alice, Bob, and Charlie are labeled a, b, and c, respectively. The measurement results for all three users across all measurement bases are recorded as 1 or 0. ;

[0021] When all three communicating parties choose the X-base, the measurements from the three parties are used to generate the original key, GHZ state. In the X-base, it is represented as:

[0022]

[0023] When all three parties simultaneously choose the X-based method to measure their own particles, the measurement results from the three parties exhibit a certain correlation. When any one party's measurement result is... When the key is 0, it indicates that the key is 0; when the measurement result is... When the key is 1, it indicates that the measurement results of the three parties are correlated.

[0024] Furthermore, in the security detection step 5, all three parties select the Z-based method to measure photons, and all three parties publish their measurement results. If the measurement results of the three parties are identical, then they are all considered to be... or both If the error rate is within the set threshold, the measurement result is correct; otherwise, the measurement result is incorrect. After the security test is completed, the three parties calculate the error rate of the security test. If the error rate of the security test is lower than the set threshold, the security test is passed, and the three parties consider the communication to be secure. Bob and Charlie then retain their respective subkeys and proceed to the next step. If the error rate exceeds the set threshold, the three parties consider the communication to be insecure. Bob and Charlie then discard the generated subkeys, terminate the communication, and re-check the channel.

[0025] Furthermore, regarding the photon intercepted by Eve, if Eve chooses the same measurement basis as Bob, and Eve selects the Z basis to measure the photon, then prepares a light pulse based on the measurement result (i.e., the power of the light pulse is slightly greater than the response power of Bob's detector as stated in the manual), and sends it to Bob through an ideal quantum channel. Bob also chooses the Z basis for measurement, and Bob's detector will respond without causing an error. However, if Eve chooses a different measurement basis than Bob, and Eve selects the X basis to measure the photon while Bob selects the Z basis to measure the pulse, then the power of the light pulse entering Bob's detector is only half of the original power, insufficient to cause a response at Bob's detector. Bob then concludes that the photon transmission has been lost. Since the transmission efficiency of photons in optical fibers is... , Let d be the actual transmission distance of photons in the optical fiber, indicating that the photon transmission loss rate increases exponentially with the transmission distance d. As the transmission channel lengthens, a large number of photons are lost during transmission. Eve uses a combination of strong light blinding attack and intercept-retransmission attack to hide its attack within the loss of photon transmission, thus avoiding detection by the communicating parties.

[0026] Furthermore, Charlie, the other party in the communication, needs to publish his subkey, so Eve does not need to attack Charlie's detector or the photons that Alice transmits to Charlie.

[0027] Furthermore, in step 8, after Charlie publishes his secure subkey, Bob follows the relation... k A = k B ⊕ k C By deducing Alice's measurement results, Eve obtains the key Alice transmitted, and Eve also uses the relational formula... k A = k E ⊕ k C By deducing Alice's measurement results and obtaining the key Alice transmitted, the transmission efficiency of the photons Alice sent to Bob was determined. That is, when the photon transmission distance exceeds 15 kilometers, Eve can intercept all the keys without being detected.

[0028] Beneficial effects

[0029] 1. This invention designs a strong light blinding attack method for a practical QSS system. By blinding the detector of only one communicating party and combining it with an intercept-retransmission attack, the eavesdropper can theoretically obtain all the keys without being detected when the photon transmission distance exceeds 15 kilometers.

[0030] 2. This invention is simple to operate and can be implemented under current experimental conditions. It is of great significance for studying the safety of actual QSS systems under imperfect experimental conditions. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method of the present invention.

[0032] Figure 2 This is a schematic diagram of the present invention, in which BS is a conventional beam splitter, PBS is a polarizing beam splitter, and QWP is a quarter-wave plate. Detailed Implementation

[0033] The invention will be further explained below with reference to the accompanying drawings and specific examples.

[0034] like Figure 1 As shown, this invention provides a method for a strong light blinding attack in quantum secret sharing, comprising the following steps:

[0035] User A is Alice, user B is Bob, and the probe C is Charlie. This embodiment of the quantum dialogue implementation scheme includes the following steps:

[0036] Step 1: Alice, the key sender, prepares N pairs of identical 3-photon-GHZ states, and divides the corresponding photons of all GHZ states into 3 photon sequences S. A ,S B ,S C Each photon sequence contains N photons.

[0037] N pairs of identical GHZ states are represented as:

[0038]

[0039] in, H Indicates horizontal polarization. V Indicates vertical polarization; subscripts A, B, and C indicate that the corresponding photons belong to three photon sequences S, respectively. A ,S B ,S C ;

[0040] Step 2: Photon detectors can be categorized into linear mode and Geiger mode. Bob and Charlie's photon detectors were initially in Geiger mode, responding only to single-photon signals. When Eve selects a suitable high-intensity laser pulse and applies it to Bob's photon detector, it causes Bob's detector to enter linear mode. In this mode, Bob's photon detector only responds to strong light signals, meaning the power of the incident light pulse is greater than the detector's response power, and it does not respond to single-photon signals.

[0041] The eavesdropper Eve uses a laser to generate a series of sufficiently bright pulsed lasers, which are then injected into the photon detector of the legitimate participant Bob. These pulsed lasers generate a large amount of photocurrent in a short period of time, thereby blinding Bob's photon detector and putting it in a linear operating mode, while not attacking the detector of the legitimate participant Charlie.

[0042] Step 3: Alice will put S B ,S C The sequence of photons is transmitted to Bob and Charlie respectively through two quantum channels;

[0043] Step 4: During photon transmission, Eve intercepts some photons sent to Bob, randomly selects diagonal basis (X basis) and right-angle basis (Z basis) to measure the intercepted photons, and then prepares photon pulses with the same quantum state based on her measurement results. The power of the photon pulses is controlled to be greater than the response power of the detector at Bob's location, and sent to Bob through an ideal quantum channel. No interception is performed on the photons sent by Alice to Charlie.

[0044] Step 5: After photon transmission ends, Alice, Bob, and Charlie randomly choose either Z-based or X-based to measure the photons they hold and publish the measurement basis for each photon. If the three parties choose different bases, they discard the measurement results. If all three parties use X-based to measure the photons, Bob and Charlie each retain their measurement results as the original subkey. If all three parties use Z-based to measure the photons, they publish the measurement results for security testing. After all photon measurements are completed, if the error rate of the security test does not exceed the set threshold, the security test passes, and the three parties consider the communication secure and proceed to the next step. If the error rate exceeds the set threshold, the three parties consider the communication insecure, and Bob and Charlie discard the generated subkey, terminate the communication, and re-check the channel. Alice, Bob, Charlie, and Eve each have two measurement basis choices, namely X-based: { , }, Z-base: { ,}, where the X basis is represented as

[0045]

[0046] The measurement results for Alice, Bob, and Charlie are labeled a, b, and c, respectively. The measurement results for all three users across all measurement bases are either 1 or 0. ;

[0047] The GHZ state is represented in the X basis as:

[0048]

[0049] When all three parties simultaneously choose X-based methods to measure their own particles, there is a certain correlation between their measurement results. Bob can infer Alice's measurement results based on Charlie's measurement results.

[0050] Step 6: For the photon intercepted by Eve, after Bob publishes the measurement basis, if both Eve and Bob choose the X basis for measurement, Eve's measurement result will be the same as Bob's measurement result, meaning Eve has obtained Bob's subkey. If both Eve and Bob choose the Z basis for measurement, Bob's measurement result will not cause a security detection error. If Eve and Bob choose different measurement bases for measurement, since Bob's photon detector is in linear mode, Bob's detector will not respond, and Bob will assume that the photon transmission has been lost. Therefore, due to the blinding attack on Bob's photon detector, Eve's intercept-retransmission attack will not increase the security detection error rate, allowing Eve to obtain part of Bob's subkey without being detected.

[0051] When the measurement result of either party is When the key is 0, it indicates that the key is 0; when the measurement result is... When the key is 1, let the key for Alice, Bob, Eve, and Charlie be 1. k A , k B , k E , k C .

[0052] In the security testing, all three parties chose the Z-base to measure photons, and all three parties published their measurement results. If the measurement results of the three parties are all the same, they are considered to be... or both If the error rate is within the set threshold, the measurement result is correct; otherwise, it is incorrect. After the security check, the three parties calculate the error rate. If the error rate is below the set threshold, the security check passes, and all three parties consider the communication secure. Bob and Charlie then retain their respective subkeys and proceed to the next step. If the error rate exceeds the set threshold, all three parties consider the communication insecure. Bob and Charlie then discard their generated subkeys, terminate the communication, and re-check the channel.

[0053] Step 7: Alice, Bob, Charlie, and Eve repeat steps 1-6 above until Bob and Charlie obtain a sufficient number of subkeys;

[0054] Step 8: Through post-processing and privacy amplification, the three parties ultimately enable Bob and Charlie to obtain the secure subkey.

[0055] After Charlie publishes his secure subkey, Bob can use the relational formula... k A = k B ⊕ k C By deducing Alice's measurement results, the key Alice transmitted can be obtained. Similarly, Eve can also deduce the key based on the relation. k A = k E ⊕ k C From this, we can deduce Alice's measurement results and obtain the key Alice transmitted. Theoretically, the transmission efficiency of the photons Alice sends to Bob... This means that when the photon transmission distance exceeds 15 kilometers, Eve can intercept all the keys without being detected.

[0056] The specific implementation schemes described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific implementation schemes of the present invention and are not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for strong light blinding attack in quantum secret sharing, characterized in that, The method includes the following steps: Step 1: Alice, the key sender, prepares N pairs of identical 3-photon-GHZ states, and divides the corresponding photons of all GHZ states into 3 photon sequences S. A ,S B ,S C Each photon sequence contains N photons; Step 2: Eve, the eavesdropper, uses a laser to generate a series of sufficiently bright pulsed lasers and injects them into Bob's photon detector. These pulsed lasers generate a large amount of photocurrent in a short time, thereby blinding Bob's photon detector and putting it in a linear working mode, while not attacking Charlie's detector. Step 3: Alice will put S B ,S C The sequence of photons is transmitted to Bob and Charlie respectively through two quantum channels; Step 4: During photon transmission, Eve, the eavesdropper, intercepts some photons sent to Bob. She randomly selects diagonal and rectangular bases to measure the intercepted photons, where the diagonal base is X-based and the rectangular base is Z-based. Then, based on her measurement results, she prepares photon pulses with the same quantum state. The power of the photon pulses is controlled to be greater than the response power of the detector at Bob's location. The pulses are then sent to Bob through an ideal quantum channel. No interception is performed on the photons sent by Alice to Charlie. Step 5: After photon transmission ends, Alice, Bob, and Charlie randomly select either Z-base or X-base to measure the photons in their hands and publish the measurement basis for each photon. If the three parties choose different bases, they discard the measurement results. If all three parties use X-base to measure the photons, Bob and Charlie retain their own measurement results as the original subkeys. If all three parties use Z-base to measure the photons, they publish the measurement results for security testing. After all photon measurements are completed, if the error rate of the security test does not exceed the set threshold, the security test passes, and the three parties consider the communication secure and proceed to the next step. If the error rate exceeds the set threshold, the three parties consider the communication insecure, and Bob and Charlie discard the generated subkeys, terminate the communication, and re-check the channel. Step 6: For the photon intercepted by Eve, after Bob publishes the measurement basis, if both Eve and Bob choose the X basis for measurement, Eve's measurement result is the same as Bob's measurement result, meaning Eve has obtained Bob's subkey. If both Eve and Bob choose the Z basis for measurement, Bob's measurement result will not cause a security detection error. If Eve and Bob choose different measurement bases for measurement, since Bob's photon detector is in linear mode, Bob's detector will not respond, and Bob will think that the photon transmission has been lost. Therefore, due to the blinding attack on Bob's photon detector, Eve's intercept-retransmission attack will not increase the security detection error rate, allowing Eve to obtain part of Bob's subkey without being detected. Step 7: Alice, Bob, Charlie, and Eve repeat steps 1-6 above until Bob and Charlie obtain a sufficient number of subkeys; Step 8: Through post-processing and privacy amplification, the three parties finally enable Bob and Charlie to obtain the secure subkey. Charlie then publishes his secure subkey. Bob, based on his own subkey and Charlie's subkey, finally deduces the key transmitted by Alice. Similarly, Eve, based on her own subkey and the subkey published by Charlie, also obtains part of the key transmitted by Alice.

2. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: The N pairs of identical GHZ states prepared by Alice in step 1 are represented as follows: in, H Indicates horizontal polarization. V Indicates vertical polarization; subscripts A, B, and C indicate that the corresponding photons belong to three photon sequences S, respectively. A ,S B ,S C .

3. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: In step 2, the photon detectors are divided into linear mode and Geiger mode. Bob and Charlie's photon detectors were originally in Geiger mode, and the detectors only responded to single-photon signals. When Eve selected a suitable high-intensity pulsed laser and applied it to Bob's photon detector, Bob's photon detector entered linear mode. At this time, Bob's photon detector only responded to strong light signals, that is, the power of the incident light pulse was stronger than the detector's response power and it did not respond to single-photon signals.

4. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: In steps 4 and 5, Alice, Bob, Charlie, and Eve each have two measurement basis choices, referring to the X basis: { , }, Z-base: { , }, where the X basis is represented as The measurement results for Alice, Bob, and Charlie are labeled a, b, and c, respectively. The measurement results for all three users across all measurement bases are recorded as 1 or 0. ; When all three communicating parties choose the X-base, the measurements from the three parties are used to generate the original key, GHZ state. In the X-base, it is represented as: When all three parties simultaneously choose the X-based method to measure their own particles, the measurement results from the three parties are correlated to some extent.

5. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: In the security check of step 5, all three parties select the Z-base to measure photons, and all three parties publish their measurement results. If the measurement results of the three parties are all the same, then they are all considered to be... or both If the error rate is within the set threshold, the measurement result is correct; otherwise, the measurement result is incorrect. After the security test is completed, the three parties calculate the error rate of the security test. If the error rate of the security test is lower than the set threshold, the security test is passed, and the three parties consider the communication to be secure. Bob and Charlie then retain their respective subkeys and proceed to the next step. If the error rate exceeds the set threshold, the three parties consider the communication to be insecure. Bob and Charlie then discard the generated subkeys, terminate the communication, and re-check the channel.

6. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: In step 6, for the photon intercepted by Eve, if Eve selects the same measurement basis as Bob, Eve selects the Z-basis to measure the photon, and then prepares a light pulse based on the measurement result. The power of the light pulse is slightly greater than the response power of Bob's detector, and it is sent to Bob through an ideal quantum channel. Bob also selects the Z-basis for measurement, and his detector will respond without causing an error. However, if Eve selects a different measurement basis than Bob, Eve selects the X-basis to measure the photon, while Bob selects the Z-basis to measure the pulse. In this case, the power of the light pulse entering Bob's detector is only half of the original power, insufficient to cause a response from Bob's detector. Bob determines that the photon has been lost during transmission. Since the transmission efficiency of photons in optical fibers is... , d is the actual transmission distance of photons in the optical fiber, indicating that the transmission loss rate of photons increases exponentially with the transmission distance d. As the transmission channel lengthens, a large number of photons are lost during transmission. Eve uses a combination of strong light blinding attack and intercept-retransmission attack to hide her attack in the loss of photon transmission, so as not to be detected by the communicating party.

7. The method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: The other communicator, Charlie, is ultimately required to disclose his subkey, and Eve is not required to attack Charlie's detector or the photons that Alice transmits to Charlie.

8. A method for strong light blinding attack in quantum secret sharing according to claim 1, characterized in that: In step 8, after Charlie publishes his secure subkey, Bob follows the relation... k A = k B ⊕ k C By deducing Alice's measurement results, Eve obtains the key Alice transmitted, and Eve also uses the relational formula... k A = k E ⊕ k C By deducing Alice's measurement results and obtaining the key Alice transmitted, the transmission efficiency of the photons Alice sent to Bob was determined. That is, when the photon transmission distance exceeds 15 kilometers, Eve can intercept all the keys without being detected.

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