Method and system for error correction in quantum cryptography.

Abstract

Provided are a quantum cryptographic communication method and system that reduce the time and cost associated with an error correction process and improve security by appropriately determining, according to the situation, the main bodies of the encoding process and the decoding process that are necessary when performing the error correction process. 【Solution means】A quantum cryptographic communication method between a first communication device and a second communication device according to the present invention includes a quantum communication step in which the first communication device transmits a first information sequence generated by randomly modulating the phase and polarization of photons to the second communication device, and the second communication device generates a second information sequence based on the first information sequence, and a post-processing step of making the first information sequence and the second information sequence identical and matching under an error correction mode selected based on a predetermined criterion, wherein the error correction mode is classified according to the main body of decoding of parity information.

Description

[Technical Field]

[0001] This invention relates to a quantum cryptography communication method and system. [Background technology]

[0002] Quantum cryptography is a technology that prevents hacking by using light "particles" to generate indivisible quanta, creating and distributing a decryptable encryption key between the sender and receiver. Quantum cryptography is a technology that securely distributes encryption keys between the sender and receiver through quantum communication, and is also called quantum key distribution (QKD).

[0003] Quantum cryptography communication consists of a quantum communication step in which the sender and receiver each generate their respective information sequences, and a post-processing step in which they make their respective information sequences identical to each other. The quantum cryptography communication process is explained below with reference to Figures 1 and 2.

[0004] First, in the quantum communication step (S10), the sender Alice randomly generates an information sequence. When using light, the information is randomly modulated by phase, polarization, etc., and encoded to generate the first information sequence. The sender Alice transmits the first information sequence to the receiver Bob via a communication channel such as wired or wireless. The receiver Bob generates his own second information sequence based on the received first information sequence. For example, the receiver Bob generates the second information sequence by performing a measurement on the first information sequence (by randomly selecting a polarization basis). In other words, the receiver Bob will have an information sequence different from that of the sender Alice.

[0005] Next, the post-processing step (S20) is the process of making the different information sequences held by the sender and receiver identical. The post-processing step includes a shifting process, an information reconciliation process, and a privacy amplification process. The shifting process is the process of using the basis used in generating the respective information sequences (first and second information sequences) of sender Alice and receiver Bob to leave only the information sequences that have the same basis. The information reconciliation process is the process of making the information sequences remaining after the shifting process of sender Alice and receiver Bob identical using error correction codes. The privacy amplification process is the process of removing from the respective information sequences of sender Alice and receiver Bob an amount of information corresponding to the amount of information that is judged to have been exposed to eavesdropper Eve in the quantum communication step or post-processing step, or the amount of information that is judged to have been exposed, after the information reconciliation process has been performed. The information sequences that remain after the privacy amplification process are the cryptographic keys that were finally delivered to Alice and Bob. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention has been made in view of the above-mentioned prior art, and the object of the present invention is to provide a quantum cryptographic communication method and system with improved security. [Means for solving the problem]

[0007] A quantum cryptographic communication method between at least one first communication device and at least one second communication device, performed by at least one processor according to one aspect of the present invention made to achieve the above objective, comprises: a quantum communication step in which the first communication device transmits a first information sequence generated by randomly modulating the phase and polarization of photons to the second communication device, and the second communication device generates a second information sequence based on the first information sequence; and a post-processing step in which the first information sequence and the second information sequence are made identical using parity information under an error correction mode selected based on predetermined criteria, wherein the error correction mode is such that the first communication device encodes the first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence The predetermined criteria are one of the following: a first error correction mode that aligns the first information sequence with the second information sequence, and a second error correction mode in which the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to align the first information sequence with the second information sequence. The predetermined criteria include a first criterion in which the first communication device and the second communication device in which the detector is not located encode the parity information, and the first communication device and the second communication device in which the detector is located decodes the parity information, and a second criterion in which either the first communication device or the second communication device decodes the parity information based on signaling information that includes information about the entity performing the decoding of the parity information.

[0008] The at least one second communication device comprises a plurality of communication devices, and the post-processing step between the first communication device and the plurality of communication devices may be performed according to the first standard. The at least one second communication device comprises a plurality of communication devices, and the post-processing step between the first communication device and the plurality of communication devices may be performed according to the second standard.

[0009] A quantum cryptographic communication method between at least one first communication device and at least one second communication device, performed by at least one processor according to another aspect of the present invention made to achieve the above objective, comprises: a quantum communication step in which the first communication device transmits a first information sequence generated by randomly modulating photons by phase and polarization to the second communication device, and the second communication device generates a second information sequence based on the first information sequence; and a post-processing step in which the first information sequence and the second information sequence are made identical using parity information under an error correction mode selected based on predetermined criteria, wherein the error correction mode is such that the first communication device encodes the first parity information and transmits it to the second communication device, and the second communication device encodes the code The error correction mode is one of two modes: a first error correction mode in which the second information sequence is made identical to the first information sequence by decoding the first parity information that has been encoded; or a second error correction mode in which the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence. The predetermined criteria are such that the first error correction mode is selected when the eavesdropper is located closer to the second communication device than to the first communication device, and the second error correction mode is selected when the eavesdropper is located closer to the first communication device than to the second communication device.

[0010] A quantum cryptography communication system according to one aspect of the present invention, made to achieve the above objective, comprises: a first communication device for transmitting a first information sequence generated by randomly modulating the phase and polarization of photons to a second communication device; and a second communication device for generating a second information sequence based on the received first information sequence, wherein quantum key distribution is performed by an error correction process that uses parity information to make the first information sequence and the second information sequence identical under an error correction mode selected based on predetermined criteria, the error correction mode includes a first error correction mode in which the first communication device encodes the first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence, and The predetermined criterion is one of the following: a second communication device encodes second parity information and transmits it to the first communication device, and a second error correction mode in which the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence, and the predetermined criterion includes a first criterion in which the first communication device and the second communication device in which the detector is not located encode the parity information and the first communication device and the second communication device in which the detector is located decodes the parity information, and a second criterion in which either the first communication device or the second communication device decodes the parity information based on signaling information which includes information about the entity that decodes the parity information.

[0011] A quantum cryptographic communication system according to another aspect of the present invention made to achieve the above objective comprises: a first communication device for transmitting a first information sequence generated by randomly modulating the phase and polarization of photons to a second communication device; and a second communication device for generating a second information sequence based on the received first information sequence, wherein quantum key distribution is performed by an error correction process that aligns the first information sequence and the second information sequence identically using parity information under an error correction mode selected based on predetermined criteria, the error correction mode is determined by the first communication device encoding the first parity information and transmitting it to the second communication device, and the second communication device decoding the encoded first parity information. The error correction mode is one of two modes: a first error correction mode that aligns the second information sequence with the first information sequence; and a second error correction mode in which the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to align the first information sequence with the second information sequence. The predetermined criteria are that if the eavesdropper is located closer to the second communication device than to the first communication device, the error correction mode is selected as the first error correction mode; and if the eavesdropper is located even closer to the first communication device than to the second communication device, the error correction mode is selected as the second error correction mode. [Effects of the Invention]

[0012] According to the present invention, by appropriately determining the main components of the encoding and decryption processes required when performing the error correction process according to the situation, it is possible to provide a quantum cryptographic communication method and system that reduces the time and cost of the error correction process and improves security. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows a flowchart of a quantum cryptography communication method according to one embodiment. [Figure 2] This figure shows a quantum cryptography communication system according to one embodiment. [Figure 3] It is a diagram showing an information correction process performed in normal mobile communication according to an embodiment. [Figure 4] It is a diagram showing a first error correction mode according to an embodiment. [Figure 5] It is a diagram showing a second error correction mode according to an embodiment. [Figure 6] It is a diagram showing quantum key distribution based on a one-way scheme according to an embodiment. [Figure 7] It is a diagram showing quantum key distribution based on a two-way scheme according to an embodiment. [Figure 8] It is a diagram showing quantum key distribution between a smartphone and an ATM device according to an embodiment. [Figure 9] It is a diagram showing a state where eavesdropper Eve is near Alice according to an embodiment. [Figure 10] It is a diagram showing a state where eavesdropper Eve is near Bob according to an embodiment. [Figure 11] It is a diagram showing signaling information for distinguishing the subject of encoding and decoding of parity information according to an embodiment. [Figure 12] It is a diagram showing a one-to-many quantum key distribution system according to an embodiment. [Figure 13] It is a diagram showing decoding of parity information using a basic setting without using signaling information according to an embodiment. [Figure 14] It is a diagram showing decoding of parity information using only one bit as signaling information according to an embodiment. [Figure 15] It is a diagram showing decoding of parity information by individually specifying the subject of decoding of parity information using an additional bit according to an embodiment. [Figure 16] It is a diagram showing a many-to-many quantum key distribution system according to an embodiment.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, specific examples of embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[0015] In the following, several embodiments will be described clearly and in detail with reference to the drawings, so that a person with ordinary skill in the art to which the present invention belongs (hereinafter referred to as an ordinary technician) can easily implement the present invention.

[0016] Figure 2 shows a quantum cryptography communication system according to one embodiment.

[0017] Referring to Figure 2 below, Alice and Bob are the sender and receiver of the information sequence, respectively. Alice and Bob refer to the first communication device owned by Alice and the second communication device owned by Bob, respectively. Communication devices include all forms of electronic devices capable of communication, such as telephones, computers, laptop computers, mobile devices, server devices, cloud devices, satellite devices, access points (APs), home appliances, and commercial electronic devices. For example, Alice is a smartphone and Bob is an ATM machine.

[0018] In communications, information correction or error correction refers to the process of correcting information so that the sender and receiver can have identical information.

[0019] Figure 3 shows the information correction process performed in normal mobile communication according to one embodiment.

[0020] Referring to Figure 3, in typical mobile communications, the error correction process involves transmitting the information sequence (actual data) and the additional information (e.g., parity bit) via the communication channel by adding additional information (e.g., parity bit) to the information sequence known only to the sender. The receiver then uses the received information to reconstruct their own information sequence to be identical to the information sequence held by the sender.

[0021] Such error correction is also performed in the quantum cryptography communication system 100. Hereinafter, the additional information used for error correction will be referred to as the "error correction code," and "parity information" will be described as a typical embodiment of the error correction code, however, the error correction code is not limited in any way to parity information. In the quantum cryptography communication system 100, such information correction is performed after the quantum communication step (step S10 in Figure 1) is completed, by transmitting additional information (i.e., parity information) to the information sequence (first information sequence or second information sequence) held by the sender and receiver. That is, unlike normal mobile communication, the error correction code in quantum cryptography communication is utilized in a post-processing step that is after the quantum communication step is completed, and the error correction process is performed with the sender and receiver already possessing their respective information sequences. Therefore, the error correction process is performed under the premise that the communication channel is being intercepted by an eavesdropper. That is, because the communication channel is being intercepted, the information transmitted through the communication channel needs to be kept to a minimum.

[0022] Figure 4 shows a first error correction mode according to one embodiment, and Figure 5 shows a second error correction mode according to one embodiment. Figure 6 shows quantum cryptographic communication based on a one-way method according to one embodiment, and Figure 7 shows quantum cryptographic communication based on a two-way method according to one embodiment. Figure 8 shows quantum cryptographic communication between a smartphone and an ATM machine according to one embodiment. Figure 9 shows a state in which the eavesdropper Eve is near Alice according to one embodiment, and Figure 10 shows a state in which the eavesdropper Eve is near Bob according to one embodiment.

[0023] Figure 4 shows a first error correction mode in one embodiment, where Alice encodes the parity information and Bob decodes the parity information. Figure 5 shows a second error correction mode in one embodiment, where Bob encodes the parity information and Alice decodes the parity information.

[0024] Parity information undergoes an encoding process performed by the sender and a decoding process performed by the receiver. That is, when the sender of parity information encodes the parity information and sends it to the other party in the communication, the other party, i.e., the receiver of the parity information, decodes the received parity information. Generally, the decoding process takes longer and is more computationally complex than the encoding process. In typical mobile communication, the information sender Alice encodes the parity information, and the information receiver Bob decodes the parity information.

[0025] However, in the quantum cryptography communication system 100, (after the quantum cryptography step is completed), the sender Alice and the receiver Bob already possess their respective information sequences. Therefore, in the quantum communication step (S10), Alice is the sender of the information sequence and Bob is the receiver of the information sequence, but separately, in the post-processing step (S20), Alice and Bob become the receiver or sender of parity information, respectively.

[0026] In one embodiment, Alice encodes the parity information, then transmits the encoded parity information to Bob via a communication channel. Bob decodes the received parity information using a second information sequence he already possesses, thereby aligning the second information sequence with the first information sequence. Bob then sends a feedback signal to Alice regarding the decoding result or any additional information required. This is referred to as the first error correction mode (see Figure 4).

[0027] In another embodiment, after Bob encodes the parity information, he transmits the encoded parity to Alice via a communication channel, and Alice decodes it using the received parity information and a first information sequence she already possesses, thereby aligning the first information sequence with the second information sequence. Alice then sends a feedback signal to Bob regarding the decoding result or any additional information required. This is referred to as the second error correction mode (see Figure 5). 4 and figure 5Referring to this, in quantum cryptography, sending and receiving parity information after the quantum communication step is completed does not necessarily mean that the sender of the information sequence must encode and transmit the parity information, and the receiver of the information sequence must decode the received parity.

[0028] However, since the parity information transmitted in the first error correction mode is generated based on the first information sequence held by Alice, and the parity information transmitted in the second error correction mode is generated based on the second information sequence held by Bob, the parity information generated according to the error correction mode may differ from each other (the first parity in Figure 4 and the second parity in Figure 5 are different from each other).

[0029] Based on predetermined criteria, either the first error correction mode or the second error correction mode is determined. The predetermined criteria for determining the entities (Alice and Bob) responsible for encoding and decoding the parity information are disclosed below.

[0030] The first criterion (the first criterion) is that, considering the high computational complexity of the decoding process, the entity with better hardware equipment should perform the decoding of parity information.

[0031] The execution of quantum communication steps in quantum cryptography can be broadly divided into one-way and two-way (plug and play) methods. Referring to Figure 6, in the one-way method, the laser for generating photons that can carry information is located at the sender Alice, and the detector for detecting the photons is located at the receiver Bob. In contrast, referring to Figure 7, in the two-way method, a bulky and high-cost laser and detector are simultaneously located at either the sender Alice or the receiver Bob (Bob in Figure 7). Based on the first criterion, the entity with the better hardware equipment among Alice and Bob performs the parity information decryption process.

[0032] The bidirectional method is used to compensate for polarization changes and path fluctuations that occur during quantum key distribution via optical fiber, despite the reduction in transmission speed. For example, when quantum cryptographic communication is performed between a portable terminal such as a smartphone and a bank's ATM machine, the portable terminal is a lightweight device with limitations in memory and processor performance, so the laser and detector are located on the ATM machine.

[0033] In one embodiment, it is determined that the entity in which the detector is located has better hardware performance than Alice or Bob. If Alice is a smartphone and Bob is an ATM machine in which the laser and detector are located, then parity information decoding is performed by Bob and encoding is performed by Alice (see Figure 8).

[0034] The second criterion is that the entity closer to the eavesdropper, either Alice or Bob, will decode the parity information, while the other entity will encode it. Communication channels (whether wired or wireless) generally have transmission loss, meaning that the signal strength is high near the sender, but the receiver may receive a weakened signal. If the eavesdropper Eve is located closer to either Alice or Bob, Eve can eavesdrop on the parity signal from the entity located closer. If Alice is the sender of the parity information and Eve is near Alice (see Figure 9), Eve can receive the parity signal more strongly than Bob, and thus receive more information than when Eve is near Bob (see Figure 10). In other words, when Eve is near Alice, Bob is determined to be the sender of the parity information, reducing the amount of information Eve receives. In other words, to conclude, it is decided that the subject located relatively close to the eavesdropper will decode the parity information, while the subject located further away will encode the parity information.

[0035] As an example of the second criterion, in quantum cryptography communication between a ground station and a satellite, considering that it is difficult for the satellite to receive equipment updates, a laser and detector are positioned at the ground station. However, since an eavesdropping satellite may be orbiting the target satellite, the ground station performs parity encoding, and the satellite decodes the parity information. Under these circumstances, according to the first criterion, the ground station where the detector is located must decode the parity information, but according to the second criterion, the satellite decodes the parity information. In other words, when the location of the eavesdropper is relatively clear, the second criterion takes precedence over the first criterion, and when applying the second criterion, it must be considered that the location of the eavesdropper may change in order to determine who is responsible for decoding the parity information.

[0036] The third criterion is that, depending on the situation, the quantum cryptography communication system 100 or the communication entity or operator of the quantum cryptography communication system 100 designates itself as the entity responsible for decrypting the parity information. In such an embodiment, a protocol for pre-agreed signaling information is specified, and the entity responsible for decrypting and encoding the parity information is determined based on the defined signaling information. Such signaling information is all the more important because the error correction process does not end with a single transmission of parity information between Alice and Bob, and additional parity transmissions may occur. For example, Alice encodes the parity information, Bob receives and decrypts the parity, Bob, as the decrypting entity, performs encoding to generate additional parity information, and this additional parity information is transmitted back to Alice. Alice then decrypts the received additional parity information again. In other words, signaling information is needed that indicates who the entity responsible for encoding the initial parity information will be.

[0037] Figure 11 shows signaling information for distinguishing the main components of parity information encoding and parity information decoding according to one embodiment.

[0038] Signaling information is information that indicates which of the sender and receiver is responsible for decoding (or encoding) the (initial) parity. If signaling information is not transmitted between Alice and Bob, the system is basically set up so that the entity with the detector performs the parity decoding (first criterion).

[0039] The signaling information consists of a bit sequence of size m (where m is an integer). If m is 1, the signaling information consists of 1 bit; if m is 2, the signaling information consists of 2 bits.

[0040] Signaling information is transmitted, and if the signaling information is "0", the parity information is decoded by an entity that does not have a detector. If the signaling information is "1", the entity to decode the parity information is individually designated by the quantum cryptography communication system 100. That is, the quantum cryptography communication system 100 designates either Alice or Bob to decode the parity information. In this embodiment, the signaling information includes an additional 1 bit, making it a total of 2 bits in size, and the entity that should decode the parity is designated based on the signaling information. For example, if the value of the additional bit is "0", Alice decodes the parity information, and if it is "1", Bob decodes the parity information.

[0041] In one embodiment, the signaling information is basically composed of 2 bits. For example, if the signaling information is "00", the entity with the detector decodes the parity information, and if it is "01", the entity without the detector decodes the parity information. If the signaling information is "10", it indicates that both Alice and Bob are capable of encoding or decoding. If the signaling information is "11", the entity that performs the initial encoding or decoding of the parity information is specified to be either Alice or Bob.

[0042] For example, Alice initially encodes the parity information, Bob receives and decodes the parity, Bob, as the decoding entity, performs encoding to generate additional parity information, and this additional parity information is transmitted back to Alice. Alice then decodes the received additional parity information again. That is, assuming a situation where the error correction process is not completed with a single parity transmission, the signaling information is composed of 2 bits. In one embodiment, if the upper bit of the 2-bit signaling information is a specific value (e.g., 1), it means that the error correction process is not completed with a single parity transmission, and it is determined which entity, Alice or Bob, will perform the encoding or decoding based on the value of the lower bit.

[0043] Signaling information is transmitted between Alice and Bob periodically or aperiodically during the quantum cryptographic communication method. For example, when quantum key distribution is performed, the signaling is transmitted unconditionally, periodically according to the number of quantum communication steps (S10 in Figure 1), or periodically over a certain period of time.

[0044] It will be understood by those skilled in the art that the magnitude and rules of the signaling information described above can be changed in any way, and that numerous embodiments will result according to the agreement between Alice and Bob or the protocol of the quantum communication system 100. Therefore, it should be understood that the present invention is not limited in any way to the embodiments described above with reference to Figure 11. It should be noted that the embodiments described above with reference to Figure 11 relate to a one-to-one quantum cryptographic communication system, and this also applies to one-to-many, many-to-one, or many-to-many quantum cryptographic communication systems.

[0045] Figure 12 shows a one-to-many quantum cryptography communication system according to one embodiment.

[0046] One-to-many quantum cryptography communication involves one sender, Alice, communicating with multiple recipients (Bob1, Bob2, ..., Bob N This is a method of communication with (where N is a positive number).

[0047] The one-to-many quantum cryptography communication system 200 enables one-to-one quantum cryptography communication between Alice and Bob1, one-to-one quantum cryptography communication between Alice and Bob2, ..., Alice and Bob N It consists of one-to-one quantum cryptographic communication between them. That is, the one-to-many quantum cryptographic communication system 200 consists of multiple one-to-one quantum cryptographic communications.

[0048] In the one-to-many quantum cryptography communication system 200, the signaling information indicating the entity responsible for decrypting the parity information is a set of m × N bits. m bits is the size of the signaling information in one-to-one communication, and N is the number of one-to-one quantum cryptographic communications. That is, the one-to-many quantum cryptography communication system 200 includes one-to-one quantum cryptographic communication between Alice and Bob1 via communication channel CH1, one-to-one quantum cryptographic communication between Alice and Bob2 via communication channel CH2, ..., and communication channel CH N Alice and Bob N Since it consists of one-to-one quantum cryptographic communication between the parties, the same information regarding signaling information described above, with reference to Figure 11, applies to one-to-one quantum cryptographic communication through each communication channel.

[0049] In one embodiment, in order to reduce the amount of bits transmitted for signaling information, all or at least some of the entities participating in one-to-many quantum cryptographic communication are configured to be able to use basic settings (i.e., the entity possessing the detector decrypts the parity information) without using signaling information.

[0050] Figure 13 shows a diagram illustrating the decoding of parity information using basic settings without using signaling information according to one embodiment (Receiver(Bob1, Bob2, ..., Bob N (Assume that a detector is located in each of these locations.)

[0051] The criteria for determining the entity that decrypts the parity information are unified throughout the one-to-many quantum cryptography communication system 200. In such an embodiment, instead of using m × N bits, the entity that decrypts the parity information can be determined with just one bit. In the one-to-many quantum cryptography communication system 200 according to one embodiment, the signaling information consists of only 1 bit in size, and the sender Alice and the receiver group (Bob1, Bob2, ..., Bob N One of the following is determined to be the entity responsible for decoding the parity information. For example, if the signaling information is "0", the sender Alice performs the encoding, and the receiver group (Bob1, Bob2, ..., Bob N ) performs the decryption. If the signaling information is "1", the sender Alice performs the decryption, and the recipient group (Bob1, Bob2, ..., Bob N ) performs the encoding.

[0052] Figure 14 shows a diagram illustrating the decoding of parity information using only one bit as signaling information according to one embodiment.

[0053] In one embodiment, the signaling information is configured to be 2 bits in size, with the upper bit containing a bit value indicating that the criteria for determining the entity decoding the parity information are unified, and the lower bit containing a bit value identifying the entity decoding the parity information. However, this can be configured freely and is not limited in any way.

[0054] In one embodiment, some of the one-to-one communications constituting the one-to-many quantum cryptography communication system 200 unify the criteria for determining the entity responsible for decrypting the parity information, while the remaining communications individually specify the entity responsible for decrypting the parity information. In order to individually specify the entity responsible for decrypting the parity information, the signaling information requires additional bits.

[0055] Figure 15 shows a diagram illustrating how parity information is decoded by individually specifying the subject of parity information decoding using additional bits according to one embodiment.

[0056] Using additional bits will increase the size of the signaling information.

[0057] Many-to-one quantum cryptographic communication is a method in which multiple senders (Alice1, Alice2, …, Alice N ) communicate with a single receiver Bob (N is a positive number). Since many-to-one quantum cryptographic communication has a structure opposite to that of one-to-many quantum cryptographic communication, the content described above regarding one-to-many quantum cryptographic communication is equally applicable to many-to-one quantum cryptographic communication, and thus its detailed description is omitted.

[0058] FIG. 16 is a diagram showing a many-to-many quantum cryptographic communication system according to an embodiment.

[0059] Many-to-many quantum cryptographic communication is a method in which multiple senders (Alice1, Alice2, …, Alice N ) communicate with multiple receivers (Bob1, Bob2, …, Bob K ) (N and K are positive numbers). As an example, a many-to-many quantum cryptographic communication system 300 includes one-to-one communication between Alice1 and Bob1, one-to-one communication between Alice1 and Bob2, one-to-one communication between Alice1 and Bob N and one-to-one communication between Alice2 and Bob1, one-to-one communication between Alice2 and Bob2, one-to-one communication between Alice2 and Bob n and. That is, the many-to-many quantum cryptographic communication system 300 is composed of N×K one-to-one quantum cryptographic communications.

[0060] Regarding the one-to-one quantum cryptographic communication through each communication channel, the content regarding the signaling information described above with reference to FIG. 11 is equally applicable. In the many-to-many quantum cryptographic communication system 300, the signaling information indicating the subject of decoding of the parity information is represented by bits of size m×N×K. The m bits are the size of the signaling information in one-to-one communication.

[0061] In one embodiment, all or some of the entities participating in the many-to-many quantum cryptography communication system 300 are configured to be able to use basic settings (i.e., the entity possessing the detector performs parity decryption) without using signaling information.

[0062] In one embodiment, the criteria for determining the entity responsible for decrypting parity information for the entire many-to-many quantum cryptography communication system 300 are unified. Alternatively, in the many-to-many quantum cryptography communication system 300, the senders are divided into groups (for example, Alice1 and receivers (Bob1, Bob2, ..., Bob K The first communication group between ) and Alice2 and the receivers (Bob1, Bob2, ..., Bob K Alternatively, in a many-to-many quantum cryptography communication system 300, the recipients are divided into groups (for example, a first communication group between Bob1 and the senders (Alice1, Alice2), a second communication group between Bob2 and the senders (Alice1, Alice2), and a third communication group between Bob3 and the senders (Alice1, Alice2)), and different criteria are applied to determine the entity responsible for decrypting the parity information for each group, but the criteria are unified within a single group.

[0063] In one embodiment, some of the one-to-one communications constituting the many-to-many quantum cryptography communication system 300 unify the criteria for determining the entity that decrypts the parity information, while the rest individually specify the entity that decrypts the parity. In order to individually specify the entity that decrypts the parity, the signaling information further requires additional bits to identify the decrypting entity.

[0064] In one embodiment, the above-mentioned signaling information is transmitted between the sender and receiver using methods such as Physical Downlink Control Channel (PDCCH), Enhanced Physical Downlink Control Channel (Enhanced PDCCH), Physical Downlink Shared Channel (PDSCH), Cell-specific high-layer signaling, and UE-specific high-layer signaling, such as 5G, LTE-A, LTE, and Wi-Fi.

[0065] In one embodiment, the signaling information is a portion of the distributed quantum key information. For example, the signaling information may be included in the second information sequence generated by Bob after step S10 in Figure 1, but is not limited to this.

[0066] This specification is intended to provide exemplary configurations and operations for realizing the present invention. The technical concept of the present invention includes not only the embodiments described above, but also realizations that can be obtained by simply changing or modifying the above embodiments. Furthermore, the technical concept of the present invention also includes realizations that can be easily achieved in the future by changing or modifying the embodiments described above. [Explanation of symbols]

[0067] 100, 200, 300 Quantum Cryptography Communication Systems

Claims

1. A quantum cryptographic communication method between at least one first communication device and at least one second communication device, which is performed by at least one processor, A quantum communication step in which the first communication device transmits a first information sequence generated by randomly modulating photons with phase and polarization to the second communication device, and the second communication device generates a second information sequence based on the first information sequence, The system includes a post-processing step of using parity information to align the first information sequence and the second information sequence identically under an error correction mode selected based on predetermined criteria, The error correction mode described above is: A first error correction mode in which the first communication device encodes first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence, The second error correction mode is one of the following: the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence. The aforementioned prescribed standards are: A first reference wherein the first communication device and the second communication device in which the detector is not located perform the encoding of the parity information, and the first communication device and the second communication device in which the detector is located perform the decoding of the parity information, A quantum cryptography communication method characterized by including a second criterion on which either the first communication device or the second communication device decodes the parity information based on signaling information which includes information about the entity that decodes the parity information.

2. The aforementioned at least one second communication device comprises a plurality of communication devices, The quantum cryptography communication method according to claim 1, characterized in that the post-processing step between the first communication device and the plurality of communication devices is performed in accordance with the first criterion.

3. The aforementioned at least one second communication device comprises a plurality of communication devices, The quantum cryptography communication method according to claim 1, characterized in that the post-processing step between the first communication device and the plurality of communication devices is performed in accordance with the second criterion.

4. A quantum cryptographic communication method between at least one first communication device and at least one second communication device, which is performed by at least one processor, A quantum communication step in which the first communication device transmits a first information sequence generated by randomly modulating photons with phase and polarization to the second communication device, and the second communication device generates a second information sequence based on the first information sequence, The system includes a post-processing step of using parity information to align the first information sequence and the second information sequence identically under an error correction mode selected based on predetermined criteria, The error correction mode described above is: A first error correction mode in which the first communication device encodes first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence, The second error correction mode is one of the following: the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence. The aforementioned prescribed standards are: If the eavesdropper is located closer to the second communication device than to the first communication device, the error correction mode is selected as the first error correction mode. A quantum cryptographic communication method characterized in that, when an eavesdropper is located closer to the first communication device than to the second communication device, the error correction mode is selected as the second error correction mode.

5. A first communication device for transmitting a first information sequence, generated by randomly modulating photons with phase and polarization, to a second communication device, The system comprises a second communication device for generating a second information sequence based on the first information sequence received, Quantum key distribution is performed by an error correction process that uses parity information to align the first information sequence and the second information sequence identically under an error correction mode selected based on predetermined criteria. The error correction mode described above is: A first error correction mode in which the first communication device encodes first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence, The second error correction mode is one of the following: the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence. The aforementioned prescribed standards are: A first reference wherein the first communication device and the second communication device in which the detector is not located perform the encoding of the parity information, and the first communication device and the second communication device in which the detector is located perform the decoding of the parity information, A quantum cryptography communication system characterized by including a second criterion on which either the first communication device or the second communication device decodes the parity information based on signaling information which includes information about the entity that decodes the parity information.

6. A first communication device for transmitting a first information sequence, generated by randomly modulating photons with phase and polarization, to a second communication device, The system comprises a second communication device for generating a second information sequence based on the first information sequence received, Quantum key distribution is performed by an error correction process that uses parity information to align the first information sequence and the second information sequence identically under an error correction mode selected based on predetermined criteria. The error correction mode described above is: A first error correction mode in which the first communication device encodes first parity information and transmits it to the second communication device, and the second communication device decodes the encoded first parity information to make the second information sequence identical to the first information sequence, The second error correction mode is one of the following: the second communication device encodes the second parity information and transmits it to the first communication device, and the first communication device decodes the encoded second parity information to make the first information sequence identical to the second information sequence. The aforementioned prescribed standards are: If the eavesdropper is located closer to the second communication device than to the first communication device, the error correction mode is selected as the first error correction mode. A quantum cryptography communication system characterized in that, when an eavesdropper is located closer to the first communication device than to the second communication device, the error correction mode is selected as the second error correction mode.

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