Non-locally randomized quantum extended security

Abstract

The inventors have developed a method and system to address the above problems by using entangled photons with multiple colors transmitted together with a classical data stream as a technique for detecting interception on a data stream and preventing reverse engineering to demodulate entangled bits from the data stream. In some embodiments, a time gate is used to interleave quantum signals and classical signals in order to provide quantum cryptography for optical fiber communication protocols.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 504,427, titled "NONLOCALLY RANDOMIZED QUANTUM-AUGMENTED SECURITY (NORAQUS)," filed on 25 May 2023, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Quantum networks enable the transmission of information in the form of qubits between physically separated quantum processors or other quantum devices (e.g., quantum sensors). Quantum networks can be used to enable long-distance optical quantum communication and can be implemented over standard communication optical fibers that transmit single photons with encoded information (e.g., polarization). Additional components may be required to ensure reliable transmission of quantum information over arbitrary distances. [Overview of the Initiative]

[0003] The following is a non-limiting overview of some embodiments of the present application. Some aspects of the present application relate to a system for encrypting a data stream. The system comprises an encryption channel having an optical fiber; a first photon source configured to generate a first entangled photon pair comprising a first photon and a second photon during the operation of the system, the first photon source configured to output the first photon to the encryption channel and the second photon to a time gate; a second photon source configured to generate a second entangled photon pair comprising a third photon and a fourth photon during the operation of the system, the second photon source configured to output the third photon to the encryption channel and the fourth photon to a Bell state evaluator; and an optical modulator configured to modulate photons to generate encoded photons for transmission of the data stream, the time gate being configured to output the third photon or the encoded photon to the encryption channel for transmission of the data stream in response to the reception of the second photon.

[0004] In some embodiments, the optical fiber of the encryption channel is configured to transmit light having a communication wavelength. In some embodiments, the optical fiber of the encryption channel is configured for bidirectional transmission.

[0005] In some embodiments, the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

[0006] In some embodiments, the time gate is an optical switch. In some embodiments, the first entanglement source is an atomic vapor cell-based entanglement source configured to generate entangled photon pairs having different wavelengths.

[0007] In some embodiments, the first entangled photon of the entangled photon pair has a wavelength of 1200 to 1600 nm, and the second entangled photon of the entangled photon pair has a wavelength of 700 to 900 nm.

[0008] In some embodiments, the first entangled photon has a wavelength of 1529 nm, and the second entangled photon has a wavelength of 780 nm. In some embodiments, a quantum random number generator is used to generate a gating signal that controls the time gate.

[0009] In some embodiments, the quantum random number generator is configured to detect light having polarization corresponding to the polarization state of the entangled second photon. In some embodiments, the quantum random number generator is configured to transmit a control signal to the time gate based on the polarization state of the entangled second photon.

[0010] In some embodiments, the time gate is configured to transmit light received from the optical modulator in response to the quantum random number generator detecting an entangled photon having a first polarization state, and to transmit light received from the second entanglement source in response to the quantum random number generator detecting an entangled photon having a second polarization state orthogonal to the first polarization state.

[0011] In some embodiments, the first entanglement light source is configured to generate a first entangled photon and a second entangled photon, the first entangled photon having a wavelength in the C band, and the second entanglement light source is configured to generate a third entangled photon and a fourth entangled photon, the third entangled photon having a wavelength in the O band.

[0012] In some embodiments, the optical modulator is configured to modulate light having the same wavelength as the third entangled photon. Some aspects of this application relate to a system for reading encrypted signals from a communication data stream. The system comprises an encrypted channel having an optical fiber, a first photon detector configured to receive a first entangled photon and generate a gating signal for controlling a time gate, wherein the time gate has two or more outputs and is configured to control which of the two or more outputs transmits a signal received from the optical fiber at the input of the time gate, a second photon detector configured to receive an output from the first output of the time gate and determine the entanglement state of the photon, and a third photon detector configured to receive an output from the second output of the time gate and detect a photon corresponding to a data stream.

[0013] In some embodiments, the optical fiber of the encryption channel is configured to transmit light having a communication wavelength. In some embodiments, the optical fiber of the encryption channel is configured for bidirectional transmission.

[0014] In some embodiments, the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

[0015] In some embodiments, the time gate is an optical switch. In some embodiments, the first photon detector is coupled to a quantum random number generator configured to generate the gating signal for controlling the time gate based at least partially on the output of the photon detector.

[0016] In some embodiments, the first photon detector is configured to detect light having polarization corresponding to the polarization state of the first entangled photon. In some embodiments, the quantum random number generator is configured to transmit a control signal to the time gate based on the polarization state of the entangled second photon.

[0017] In some embodiments, the time gate is configured to transmit light received from the optical fiber to the second photon detector in response to the output of the quantum random number generator that has detected an entangled photon having a first polarization state, and to transmit light received from the optical fiber to the third photon detector in response to the quantum random number generator detecting an entangled photon having a second polarization state orthogonal to the first polarization state.

[0018] In some embodiments, an unencrypted channel is further provided. In some embodiments, the output of the second photon detector and the unencrypted channel are configured to verify the security of the encrypted channel.

[0019] Some aspects of this application relate to a system for processing encrypted signals of a communication data stream. The system comprises an encryption channel having an optical fiber; a time gate having two or more inputs and two or more outputs for directing incident and outgoing photons; an optical modulator configured to modulate photons corresponding to a data stream to generate encoded photons for transmission; a first photon source configured to generate a first entangled photon pair, the first photon source configured to provide a first photon of the first entangled photon pair to the encryption channel and a second photon of the first entangled photon pair to a Bell state evaluator; and a first photon detector configured to receive the first entangled photons and generate a gating signal for controlling the time gate.

[0020] In some embodiments, the optical fiber of the encryption channel is configured to transmit light having a communication wavelength. In some embodiments, the optical fiber of the encryption channel is configured for bidirectional transmission.

[0021] In some embodiments, the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in a direction opposite to the transmission direction of the first optical fiber.

[0022] In some embodiments, the time gate is an optical switch. In some embodiments, the first photon detector is configured to detect light having a polarization corresponding to the polarization state of the first entangled photon.

[0023] ]>In some embodiments, the first photon detector is configured with a random number generator configured to transmit a control signal to the time gate based on the polarization state of the first entangled photon.

[0024] In some embodiments, the time gate is configured to transmit the light received from the optical modulator in response to the quantum random number generator detecting an entangled photon having a first polarization state, and is configured to transmit the light received from the second entangled source in response to the quantum random number generator detecting an entangled photon having a second polarization state orthogonal to the first polarization state.

[0025] In some embodiments, the first photon source is configured to generate at least one entangled photon having the same wavelength as the photon generated by the optical modulator. Some aspects of this application relate to a method for encrypting a communication optical signal using optical qubits for secure communication transmission. The method comprises generating a gating signal based on coherent photons received by a detector of a quantum random number generator; generating a first dichromatic entanglement pair comprising a first photon having a first wavelength configured for communication transmission and a second photon having a second wavelength different from the first wavelength; randomly selecting whether to transmit an encoded light source for data transmission or the first photon via an encryption channel; and detecting the state of the second photon.

[0026] In some embodiments, the encryption channel is an optical fiber configured to transmit light having a communication wavelength. In some embodiments, selecting whether to transmit the light source encoded for data transmission or the first photon over the encrypted channel includes controlling which input of the optical switch is output by the optical switch.

[0027] In some embodiments, generating the first two-color entangled pair includes generating the entangled photon pair using two-photon pumping of an atomic vapor cell. In some embodiments, the method further comprises generating the coherent photons by generating a second dichromatic entanglement pair before generating the gating signal.

[0028] In some embodiments, detecting the state of the second photon includes detecting the polarization state of the second photon. In some embodiments, the method further comprises receiving an instruction on the polarization state of the first photon via a non-quantum encryption channel, and determining whether the polarization states of the first photon and the second photon indicate that the first and second photons remained entangled after the transmission of the first photon via the encryption channel.

[0029] In some embodiments, the method further comprises receiving, via a non-quantum encryption channel, an indication of when the first photon was received after transmission through the encryption channel, and determining whether the transmitted photon is missing based on the received indication of when the first photon was received after transmission through the encryption channel and the indication of when the first photon was transmitted through the encryption channel.

[0030] Some aspects of this application relate to a method for decoding an optical signal encoded using optical qubits to receive a data stream. The method comprises generating a gating signal based on a coherent photon received by a detector of a quantum random number generator; randomly selecting whether to transmit the received photon to a first photodetector or a second photodetector; detecting a photon corresponding to an entangled photon received by the first photodetector; determining the entanglement state of the photon received by the first photodetector; and detecting a second photon corresponding to a data stream received by the second photodetector.

[0031] In some embodiments, the coherent photons received by the detector are received from an encryption channel, which is an optical fiber configured to transmit light having a communication wavelength.

[0032] In some embodiments, selecting whether to transmit the received photons to the first photodetector or to the second photodetector includes controlling which output of the optical switch is used to transmit the received photons.

[0033] In some embodiments, detecting the photon corresponding to the entangled photon includes detecting a polarization state corresponding to the polarization state of the photon received by the first photodetector.

[0034] In some embodiments, the method further comprises transmitting an instruction on the polarization state of the photon received by the first photodetector via a non-quantum encryption channel. In some embodiments, the method further comprises transmitting an instruction via a non-quantum cryptographic channel indicating when the photon is to be received by the first photodetector. [Brief explanation of the drawing]

[0035] [Figure 1] Figure 1 shows a block diagram of a quantum cryptography system according to several embodiments of the technology described herein. [Figure 2A] Figure 2A shows a method for transmitting quantum encrypted signals according to several embodiments of the technology described herein. [Figure 2B] Figure 2B shows a method for decrypting a received quantum encrypted signal according to several embodiments of the technology described herein. [Figure 3] Figure 3 shows a block diagram of a quantum cryptography system for sending and receiving quantum encrypted signals, according to some embodiments of the technology described herein. [Figure 4] Figure 4 shows a block diagram of an alternative configuration of a quantum cryptography system for sending and receiving quantum encrypted signals, according to some embodiments of the technology described herein. [Figure 5] Figure 5 shows a schematic diagram of a quantum cryptography system for sending and receiving quantum encrypted signals, according to some embodiments of the technology described herein. [Modes for carrying out the invention]

[0036] The inventors have developed a technology that advances quantum information science by developing a protocol to facilitate quantum cryptography for non-quantum data transmission infrastructure, thereby modifying versatile implementations of non-quantum data transmission protocols with quantum cryptography protocols and enhancing the security of data transmission against attackers who may attempt to intercept or copy transmitted signals.

[0037] Quantum entanglement distributions are generally seen as the most viable tool for scalable quantum networks aimed at distributed quantum computing, sensing, and secure communication. Many protocols and demonstrations exist for the latter application, proving the advantages of using entanglement for secret key sharing compared to the most commonly used methods of quantum key exchange. Most of these protocols focus on problems arising from the advancement of quantum computers and the vulnerability of public key exchange to attacks on them. However, the potential application of quantum entanglement in protecting classical communication channels to prevent attacks that are already a concern today is generally overlooked.

[0038] The inventors recognized that enhancing classical channels using quantum entanglement could enable immediate detection of intrusion threats. This enhancement provides two users at both ends of a communication system with a way to verify whether an intruder is listening to, copying, or rerouting the ciphertext during transmission. Such a protocol can reduce threat detection time to less than one second.

[0039] The inventors recognize that there are several challenges in implementing quantum entanglement protocols for threat detection over classical communication channels. The first challenge is that a known protocol is required for users of a communication system to utilize photon correlations to enhance the security of the classical channel without allowing third parties to intercept or reroute classical data without destroying the quantum entanglement. The second challenge is the need for quantum hardware that is compatible with classical communication infrastructure and can rapidly generate and maintain pure entangled pairs. In addition to enhancing existing classical infrastructure, quantum hardware can further extend distributed quantum computing and secure network infrastructure. The third challenge is integrating quantum hardware into complex multi-node networks to transmit entangled photons across communication networks.

[0040] The inventors have developed a method and system to address the above problems by using entangled photons with multiple colors transmitted together with a classical data stream as a technique for detecting interception on a data stream and preventing reverse engineering to demodulate entangled bits from the data stream.

[0041] The inventors have developed a system for encrypting a data stream, comprising: an encryption channel having an optical fiber; a first photon source configured to generate a first entangled photon pair comprising a first photon and a second photon during the operation of the system, the first photon source configured to output the first photon to the encryption channel and the second photon to a time gate; a second photon source configured to generate a second entangled photon pair comprising a third photon and a fourth photon during the operation of the system, the second photon source configured to output the third photon to the encryption channel and the fourth photon to a Bell state evaluator; and an optical modulator configured to modulate photons to generate encoded photons for transmission of the data stream, wherein the time gate is configured to output the third photon or the encoded photon to the encryption channel for transmission of the data stream in response to the reception of the second photon.

[0042] The inventors have developed a system for reading encrypted signals from a communication data stream, comprising: an encrypted channel having an optical fiber; a first photon detector configured to receive a first entangled photon and generate a gating signal for controlling a time gate, wherein the time gate has two or more outputs, and the time gate is configured to control which of the two or more outputs transmits a signal received from the optical fiber at the input of the time gate; a second photon detector configured to receive an output from the first output of the time gate and determine the entanglement state of the photon; and a third photon detector configured to receive an output from the second output of the time gate and detect a photon corresponding to the data stream.

[0043] The inventors have developed a system for processing encrypted signals of a communication data stream, comprising: an encryption channel having an optical fiber; a time gate having two or more inputs and two or more outputs for directing incident and outgoing photons; an optical modulator configured to modulate photons corresponding to the data stream to generate encoded photons for transmission; a first photon source configured to generate a first entangled photon pair, wherein the first photon source is configured to provide the encryption channel with a first photon from the first entangled photon pair and the second photon from the first entangled photon pair to a Bell state evaluator; and a first photon detector configured to receive the first entangled photons and generate a gating signal for controlling the time gate.

[0044] The inventors have developed a method for encrypting a communication optical signal using optical qubits for secure communication transmission, comprising: generating a gating signal based on coherent photons received by a detector of a quantum random number generator; generating a first dichromatic entangled pair comprising a first photon having a first wavelength configured for communication transmission and a second photon having a second wavelength different from the first wavelength; randomly selecting whether to transmit an encoded light source for data transmission or the first photon via an encryption channel; and detecting the state of the second photon.

[0045] The inventors have developed a method for decoding an optical signal encoded using optical qubits to receive a data stream, comprising: generating a gating signal based on coherent photons received by a detector of a quantum random number generator; randomly selecting whether to transmit the received photons to a first photodetector or a second photodetector; detecting a photon corresponding to an entangled photon received by the first photodetector; determining the entanglement state of the photon received by the first photodetector; and detecting a second photon corresponding to a data stream received by the second photodetector.

[0046] Figure 1 shows a block diagram of a quantum cryptography system 100 according to several embodiments of the technology described herein. The quantum cryptography system 100 includes two communication nodes, communication node 101 and communication node 103. A communication node is a network connection point that is communicatively connected via a transmission line so that data can be sent and received between the nodes. Communication node 101 and communication node 103 are communicatively connected via a transmission line 110.

[0047] The transmission line 110 is an optical fiber configured as an encrypted channel for communicatively coupling communication node 103 and communication node 101. In some embodiments, the optical fiber of the encrypted channel is configured to transmit light having a certain communication wavelength, as described herein. In some embodiments, the optical fiber of the encrypted channel is configured for bidirectional transmission. In some embodiments, the optical fiber of the encrypted channel is a first optical fiber configured for unidirectional transmission, and the encrypted channel includes one or more optical fibers, one or more of which include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

[0048] In some embodiments, a single optical fiber may be used for bidirectional data transmission. In some embodiments, bidirectional data transmission over a single optical fiber may involve using different transmission wavelengths for each transmission direction so that transmission pulses are not sent or received simultaneously, or scheduling transmissions within a specific time window.

[0049] The transmission line 110 can be any optical fiber that is suited to a transmission wavelength that at least partially depends on an entanglement light source and the corresponding wavelength that can be generated by that light source. Therefore, any material capable of low-loss photon transmission can be used for a fiber length corresponding to the distance between communication nodes. Examples of entanglement light sources and their corresponding operating wavelengths are provided below in Tables 1 and 2.

[0050] Communication node 101 includes a quantum cryptography module 102 and a data transmission module 104. The quantum cryptography module 102 is configured to generate entangled quantum states. The data transmission module 104 is configured to generate a bit-encoded signal representing data to be transmitted between nodes in the network. Communication node 101 is configured to encrypt transmissions over transmission line 110 so that the entangled quantum states generated by the quantum cryptography module 102 are transmitted together with the encoded signal generated by the data transmission module 104.

[0051] In some embodiments, the data transmission module 104 includes a moduloable light source for generating photons modulated according to an optical fiber data transmission protocol. In some embodiments, the data transmission module 104 includes a light source and an optical modulator. The light source may be a coherent light source such as a laser that supplies coherent light to the optical modulator. The optical modulator is capable of receiving data for encoding and modulating the light received from the light source according to the received data for encoding.

[0052] The quantum cryptography module 102 includes an entanglement source based on an atomic vapor cell that generates a pair of entangled photons. In some embodiments, the quantum cryptography module generates a pair of entangled photons having different wavelengths, as described herein. In some embodiments, the pair of entangled photons are entangled in polarization space. To facilitate encryption, the quantum cryptography module 102 determines the state of the entanglement attribute by locally analyzing one of the entangled photons. For example, for photons entangled in polarization space, the quantum cryptography module detects the polarization state of one of the entangled photons and provides the other entangled photon from the entangled pair to the communication node 101 for transmission. In some embodiments, the aspects of the technique described herein are not limited in this respect, and photons may be entangled in different attribute spaces.

[0053] In some embodiments, the communication node 101 encrypts the transmission by interleaving entangled photons generated by the quantum cryptography module 102 with photons encoded using data generated by the data transmission module 104. For example, interleaving entangled photons with data-encoded photons introduces a temporal variation between the transmission of entangled photons and the transmission of data photons over the transmission line 110. By temporally interleaving the photons for transmission, entangled photons are interleaved between data-encoded photons. Through the interleaving of entangled photons with data-encoded photons, a potential attack can be identified by detecting the collapse of the entangled state. To prevent a potential attacker from intercepting the interleaved signal and attempting to intercept only the data-encoded photons while keeping the entangled photons in an unperturbed state, the order of interleaving is randomized according to the encryption protocol.

[0054] In some embodiments, the transmission line 110 includes a channel fidelity device for compensating for polarization drift that occurs during transmission through the fiber. This improves signal fidelity by compensating for polarization drift that could cause artifacts when determining the polarization state of photons transmitted through the transmission line at a later stage.

[0055] Communication node 103 receives encrypted transmissions from communication node 101 via transmission line 110. Communication node 103 is configured to decrypt encrypted transmissions by transferring entangled photons to quantum cryptography module 106 and transmitting data-coded photons to data transmission module 108. An additional time-gating signal is transmitted over the entangled transmission line to facilitate the proper transfer of entangled photons and data-coded photons. In some embodiments, the time-gating signal is a second entangled photon generated as part of a second entangled pair generated by the quantum cryptography module. Thus, the second entangled pair may be used by communication node 101 to decide to interleave the signals together, and the corresponding entangled photons from the second entangled pair may be used by communication node 103 to generate a gating signal to separate the respective signals to the appropriate modules.

[0056] To monitor the security of encrypted transmissions, quantum cryptography modules 102 and 106 exchange information corresponding to the state of entangled photons, measured in each module. If entanglement is maintained, it is confirmed that data exchange between communication nodes is secure. On the other hand, if entanglement is not maintained, the security of data exchange may be compromised. In some embodiments, quantum cryptography modules 102 and 106 determine the Bell state value of the entangled photons by performing Bell state measurements. These quantum cryptography modules can then monitor entanglement between two communication nodes involved in the transmission by exchanging Bell state values ​​by sending back the Bell state value measured by the receiving quantum cryptography module to the transmitting quantum cryptography module. In some embodiments, the exchange of Bell state values ​​may be performed through an unencrypted channel separate from the transmission line 110.

[0057] In some embodiments, quantum encryption module 102 and quantum encryption module 106 are configured similarly. Data transmission module 104 and data transmission module 108 are configured similarly, as will be further described below in relation to Figures 3 and 4, so that communication node 101 and communication node 103 can each send and receive signals to and from each other.

[0058] Figure 2A shows a method 200 for transmitting a quantum encrypted signal according to some embodiments of the technology described herein. Prior to the commencement of method 200, a first photon source generates a pair of entangled photons for use in generating gating signals for encoding and decoding data transmission. One of the pair of entangled photons is locally detected at one communication node involved in the transmission to generate a gating signal, and the other entangled photon is transmitted to the corresponding communication node of that transmission to generate a corresponding gating signal. In some embodiments, the first photon source is configured on the transmitting side of the communication. Thus, one of the pair of entangled photons is detected at the transmitting node and used to generate a gating signal for encryption. The second entangled photon is transmitted to the corresponding receiving node and used at that receiving node to generate a gating signal for decoding. In some embodiments, the first photon source is configured on the receiving side of the communication. Thus, one of the pair of entangled photons is detected at the receiving node and used to generate a gating signal for decoding. The second entangled photon is transmitted to the corresponding transmitting node, where it is used to generate a gating signal for decoding.

[0059] Method 200 begins in operation 202, according to some embodiments of the technique described herein, by generating a gating signal based on a photon received by a photon detector. The photon received by the photon detector is an entangled photon produced by a first entangled photon source. In some embodiments, the entanglement is entanglement in polarization space. Thus, the gating signal is generated based on the polarization of the detected photon. The gating signal may have a first value for the first polarization and a second value for a second polarization orthogonal to the first polarization.

[0060] Method 200 then proceeds to operation 204, according to some embodiments of the technique described herein, to generate an entangled pair comprising a first photon having a wavelength set for communication transmission. A second light source generates a second entangled pair. In some embodiments, the second light source generates an entangled pair having different wavelengths. One of the entangled photons has a wavelength in the communication range, as described herein.

[0061] Method 200 then proceeds to operation 206, according to some embodiments of the technology described herein, to select, based on a gating signal, whether to transmit a light source encoded for data transmission or a first photon through the encrypted channel. The light source encoded for data transmission generates a modulated optical signal corresponding to bits for data transmission, as described herein. Selecting, based on a gating signal, whether to transmit a light source encoded for data transmission or a first photon through the encrypted channel may involve controlling an optical switch using a gating signal. The optical switch may include two inputs: a first input that receives entangled photons from a second photon source and a second input that receives photons encoded with data for transmission. Based on a gating signal, depending on one value of the gating signal, the optical switch transmits the photon received at the first input from the output of the optical switch to the encrypted channel. Depending on the other value of the gating signal, the optical switch transmits the photon received at the second input from the output of the optical switch to the encrypted channel. As the gating signal changes in time according to the random polarization of photons generated from the first light source, the output of the optical switch changes between the two inputs. Therefore, the output of the optical switch and the signal transmitted through the encryption channel are transmitted with time interleaving between the encoded photons and the entangled photons for data transmission.

[0062] After operation 206, method 200 terminates. Following the termination of the transmission of the quantum encrypted signal, a method for decrypting the signal or a method for reading the data encoded in the photon may be used. In some embodiments, following the result of method 200, an indication of when the entangled photon transmitted by the time gate over the encryption channel was detected at the receiving node is detected. Then, by comparing the indication of when the entangled photon was received at the receiving node with an indication of when the time gate transmitted the entangled photon instead of the data photon, it can be determined whether the photon was lost during transmission and not received at the receiving node. A determination that the photon is missing may suggest that the encryption channel is compromised. An indication of when the photon was received at the receiving device may be transmitted to the transmitting device over a non-quantum encrypted transmission line.

[0063] Figure 2B shows a method 210 for decrypting a received quantum encrypted signal according to several embodiments of the technology described herein. Prior to the commencement of method 210, the quantum encrypted signal may be generated according to an encryption method such as method 200 described above.

[0064] Method 210 begins in operation 212, according to some embodiments of the technique described herein, by generating a gating signal based on photons received by a photon detector. As described above with respect to Figure 2A, the first entanglement source may generate two entangled photons. One of the two entangled photons is used to encode the transmission at the transmitting node, and the other is used to decode the transmission at the receiving node. Thus, the gating signal is generated based on the entangled photons from the first entanglement source, as described herein.

[0065] Method 210 then proceeds to operation 214, according to some embodiments of the technique described herein, to select, based on a gating signal, whether to transmit the received photon to a first photodetector or a second photodetector. This selection can be easily achieved by an optical switch having an input that receives an encoded signal and two outputs. The first output of the optical switch transmits light to an entanglement detector for determining the Bell state value associated with the entangled photon. The second output of the optical switch transmits light to a photodetector for detecting the photon and decoding the encoded data represented in that photon. In some embodiments, the gating signal has a first value based on the polarization of the entangled photon from the first entanglement source, and this first value causes the optical gate to output the received photon to the entanglement detector. The gating signal also has a second value, and this second value causes the optical gate to output the received photon to a photodetector for decoding the data transmission.

[0066] Method 210 then proceeds to operation 216, according to some embodiments of the technique described herein, to detect a photon corresponding to the entangled photon received by the first photodetector. In some embodiments, the first photodetector is configured as a Bell state value detector. The Bell state value detector includes a photon detector and a polarization optical system selected to match a specific polarization of light received by the photon detector so that a Bell state value can be determined.

[0067] When a photon is detected, polarization state information about the received photon is transmitted via a non-quantum encryption channel. This information, along with the polarization state information detected for the corresponding entangled photon, is used to determine whether the entanglement is preserved and, consequently, whether the encryption remains secure.

[0068] Method 210 then proceeds to operation 208, according to some embodiments of the technique described herein, to detect photons corresponding to the data stream received by the second photodetector. The encoded photons are provided to the photon detector so that the photons are detected and a decoded data signal is determined for receiving data transmitted from the transmitting node, etc.

[0069] After operation 208, method 210 terminates. Following the results of method 210, the method may be repeated so that additional data is transmitted between communication nodes. In some embodiments, following method 210, an indication of when the entangled photon was received by the Bell state value detector is sent to the transmitting device via a non-quantum encrypted channel, etc., so that the transmitting device can determine whether the transmitted entangled photon failed to be received.

[0070] Figure 3 shows a block diagram of a quantum cryptography system 300 for sending and receiving quantum encrypted signals according to several embodiments of the technology described herein. The quantum cryptography system 300 includes two communication nodes, communication node 301 and communication node 303. Communication node 301 includes a first entanglement source 302, a second entanglement source 306, a data transmission source 308, and a first time gate 304. Communication node 303 includes a first entanglement detector 314, a second entanglement detector 318, a data transmission detector 320, and a second time gate 316. A transmission line 310 is configured to transmit encrypted signals from communication node 301 to communication node 303. An additional communication line 312 is configured to transmit and / or receive unencrypted signals between the communication nodes.

[0071] The first entanglement source is a first photon source configured to generate a first entangled photon pair during the operation of system 300. The first entangled photon pair includes a first photon and a second photon. The first photon source is configured to output the first photon to the encryption channel 310 and the second photon to the first time gate 304.

[0072] The first entanglement source 302 can be any suitable entanglement source for generating entangled photons, including at least one photon having a wavelength suitable for communication applications. Wavelengths used in communication applications are classified into different wavelength bands. Two bands commonly used for communication applications are the O band and the C band. The O band covers approximately 1260 nm to 1360 nm. The C band covers approximately 1530 nm to 1565 nm. In some embodiments, the first entanglement source 302 generates a first entangled photon in the C band and a second entangled photon in the near-IR range (e.g., approximately 800 nm to 2,500 nm).

[0073] In some embodiments, the first entanglement source comprises an atomic vapor cell and one or more lasers, the one or more lasers configured for two-photon pumping to generate an entangled polarization state in a three-level atomic system. In some embodiments, the atomic vapor cell may contain atomic vapor containing atoms, and upon receiving a pumping field (e.g., a laser beam), it may absorb received photons of a certain frequency and, after a two-step excitation and decay process, re-emit photons having an entangled polarization state. For example, the atomic vapor cell may be made of rubidium (e.g., 87 Rb, 85 It may contain atomic vapor of Rb (or any other suitable isotope). Alternatively, in some embodiments, the atomic vapor cell may contain atomic vapor of another alkali metal. For example, the alkali metal may be an isotope of cesium (e.g., 133 It may contain Cs or any other suitable isotope.

[0074] In some embodiments, atomic vapor may exhibit two-photon resonance, enabling the generation of entangled photon pairs at two desired wavelengths. For example, 87 Rb is capable of generating entangled photons with wavelengths of approximately 795 nm and 1324 nm in response to excitation by received light with wavelengths of approximately 780 nm and 1367 nm, transition |5S 1 / 2 >→|5P 3 / 2 >→|6S 1 / 2Exhibits two-photon resonance (or four-wave mixing process) along >. Alternatively or additionally, for generating photon pairs having wavelengths of approximately 1367 nm and 780 nm, approximately 1476 nm and 795 nm, and / or approximately 1529 nm and 780 nm 87 By using two-photon resonance in Rb vapor, an adaptable photon source can be provided that can be used to generate spectra of wavelengths in the NIR band, O band, C band, and / or S band. These specific bands have a wide range of applications across quantum communication and computing. For example, wavelengths of 1324 nm, 1476 nm, and 1529 nm correspond to the O communication band, S communication band, and C communication band, respectively, and are wavelengths suitable for long-distance optical fiber communication. Also, wavelengths of 795 nm and 780 nm are commonly used for quantum buffers and sensors.

[0075] This exemplary transition cycle provides little path for photons to spontaneously decay to the ground state, providing a higher entanglement rate and fewer output uncorrelated photons. Note that other isotopes of rubidium or other atomic systems may also have other similar two-photon resonances. As a further example, 87 Rb system and 133 The potential wavelengths of photon pairs that can be generated in the Cs system are provided in Tables 1 and 2, respectively. These additional exemplary wavelengths can be used to interface with some Rydberg and ion technologies such as neutral quantum computers and sensors.

[0076] [Table 1]

[0077] [Table 2-1]

[0078] [Table 2-2] <f

[0079] The second entanglement source 306 is a second photon source configured to generate a second entangled photon pair during the operation of the system 300. The second entangled photon pair includes a third photon and a fourth photon. The second photon source is configured to output the third photon to the encryption channel and the fourth photon to the Bell state evaluator. In some embodiments, the second entanglement source 306 is configured similarly to the first entanglement source 302. For example, the second entanglement source 306 may contain the same atomic gas vapor and be configured to generate the same wavelength as the first entanglement source. In some embodiments, the second entanglement source 306 is configured differently from the first entanglement source 302. For example, the second entanglement source may be an atomic gas vapor entanglement source configured to generate a different wavelength than the first entanglement source. The first entanglement source may be configured to generate an entangled pair having a first photon in the C band and a second photon in the near-IR range, while the second entanglement source may be configured to generate an entangled pair having a first photon in the O band and a second photon in the near-IR range.

[0080] The first time gate 304 is configured to, in response to receiving a second photon, output a third photon generated by the second photon source or an encoded photon generated by the optical modulator to the encryption channel. In some embodiments, the first time gate may be configured to transmit light to the encryption channel by sending a trigger signal to the second entanglement source 306 and the data transmission source 308, thereby controlling one of the two sources when the trigger signal is triggered. In some embodiments, the first time gate may be an optical switch. The optical switch is configured to receive a photon from the second entanglement source 306 at its first input and a photon from the data transmission source 308 at its second input. In response to receiving a second photon from the first entanglement source 302, the optical switch outputs a photon from the entanglement source 306 or a photon from the data transmission source 308 to the encryption channel 310. For example, when the second photon has the first polarization, the photon from the second entanglement source 306 can be output from the optical switch. On the other hand, when the second photon has the second polarization which is orthogonal to the first polarization, the photon from the data transmission source 308 can be output from the optical switch.

[0081] In some embodiments, the encryption channel 310 is an optical fiber configured to transmit light having a communication wavelength, as described herein. The communication node 303 includes a first entanglement detector 314, a second time gate 316, a second entanglement detector 318, and a data transmission detector 320. The first entanglement detector 314 includes a photon detector configured to receive entangled photons from the encryption channel 310 and to generate a gating signal for controlling the second time gate 316. In some embodiments, the first entanglement detector 314 detects the polarization state of the received photons and generates a gating signal based on the detected polarization state. For example, a first gating value may be generated by detecting a first polarization state, and a second gating value may be generated by detecting a second polarization state orthogonal to the first polarization state.

[0082] The second time gate 316 includes two or more outputs and is configured to control which of the two or more outputs transmits the signal received from the optical fiber at the input of the time gate. In some embodiments, a gating signal received from the first entanglement detector 314 indicates whether the input from the optical fiber received by the second time gate 316 is an entangled photon to be directed to the second entanglement detector 318 via the first output, or an encoded photon to be directed to the data transmission detector 320 via the second output.

[0083] A second entanglement detector 318 is configured to determine the entanglement state of photons received from a second time gate. In some embodiments, the second entanglement detector 318 determines the polarization state of photons received from the second time gate. Once the polarization state is determined, it is compared with the polarization state determined for the corresponding entangled photon generated by the second entanglement source 306 to determine the degree of entanglement between the photons and whether the encryption channel 310 is secure. To facilitate communication of the measured polarization state, a non-quantum encrypted communication channel 312 is included to communicatively couple a first communication node 301 to a second communication node 303. For example, the polarization state detected by the second entanglement detector 318 is sent back to the communication node 301 via the communication channel 312 and compared with the polarization state of the corresponding entangled photon.

[0084] In some embodiments, the first entanglement detector 314 communicates the detected polarization state of entangled photons generated by the first entanglement source to the first communication node 301 via the communication channel 312 in order to determine the degree of entanglement between photon pairs generated by the first entanglement source.

[0085] The data transmission detector 320 is configured to decode the data signal from the photons encoded with the data by the data transmission source 308 when the second time gate 316 sends encoded photons to the data transmission detector 320. The data transmission detector 320 is a photon detector. However, the embodiments of the technology described herein are not limited in this respect, and any suitable photon detector capable of detecting photons at a suitable communication wavelength of the transmitted photons may be used.

[0086] Figure 4 shows a block diagram of an alternative configuration of the quantum cryptography system 400 for sending and receiving quantum encrypted signals, according to several embodiments of the technology described herein. The alternative configuration of the quantum cryptography system 400 includes components similar to those of the quantum cryptography system 300 described above with respect to Figure 3. With respect to the configuration of Figure 3, the quantum cryptography system 400 is configured for bidirectional communication, for example, sending and receiving quantum encrypted signals. To provide bidirectional communication, at least one entanglement source is located at each communication node. Communication node 401 includes a first entanglement detector 402, a first entanglement source 404, a first data transmission source 406, a first transmission detector 408, and a first time gate 410. Communication node 403 includes a second entanglement detector 418, a second entanglement source 422, a second data transmission source 424, a second data transmission detector 426, and a second time gate 420.

[0087] The encrypted channel 412 transmits signals from the first communication node 401 to the second communication node 403. The encrypted channel 414 transmits signals from the second communication node 403 to the first communication node 401. The communication line 416 provides non-quantum encrypted communication between these communication nodes.

[0088] The first entanglement detector 402 is used to generate a gating signal when used to transmit a quantum encrypted signal from the communication node 401. The first entanglement detector 402 includes a photon detector configured to receive entangled photons generated by the second entanglement source 422 from the encryption channel 414 and to generate a gating signal to control the first time gate 410. In some embodiments, the first entanglement detector 402 detects the polarization state of the received photons and generates a gating signal based on the detected polarization state.

[0089] The first time gate 410, when used to transmit a quantum encrypted signal from the communication node 401, is configured to receive a gating signal from the first entanglement detector 402 and cause entangled photons generated by the first entanglement source or encoded photons generated by the first data transmission source to output to the encryption channel. Thus, the first time gate 410 can operate similarly to the time gate 304 by using an optical switch to interleave the output from the first entanglement source 404 and the output from the first data transmission source 406 and transmit them through the encryption channel 412, as described herein.

[0090] The first entanglement source 404 may have the same configuration as the second entanglement source 306 described above. Therefore, the first entanglement source 404 can operate in the same way as the second entanglement source 306 to provide entangled photons for encrypting data transmission through the first time gate 410 and encryption channel 412.

[0091] The first data transmission source 406 may have the same configuration as the data transmission source 308 described above. Therefore, the first data transmission source 406 can operate in the same way as the data transmission source 308 to provide encoded photons for transmitting data through the first time gate 410 and the encryption channel 412.

[0092] The second time gate 420 receives the quantum encrypted signal via the encryption channel 412 when the communication node 401 is used to transmit the quantum encrypted signal, and also receives a gating signal from the second entanglement source 422. The gating signal from the second entanglement source 422 causes the second time gate to send the received signal to either the second entanglement detector 418 or the second data transmission detector 426.

[0093] The case of transmitting a quantum encrypted signal from communication node 401 has been described, but the same operation occurs when a quantum encrypted signal from communication node 403 is received by communication node 401. When communication node 401 is used to receive a quantum encrypted signal, the first entanglement source 404 generates an entangled photon pair, the first entangled photon is used for transmission via encryption channel 412 to generate a gating signal for the second time gate 420, and the second entangled photon is used as a gating signal for the first time gate 410, thereby directing the photon received via encryption channel 414 to an appropriate detector, namely the first entanglement detector 402 or the first data transmission detector 408.

[0094] When communication node 401 is used to receive quantum encrypted signals, the second entanglement detector 418 of the second communication node 403 receives entangled photons from the first entanglement source 404 via the encryption channel 412. In response to receiving the entangled photons, the second entanglement detector generates a gating signal for the second time gate 420, thereby controlling whether to transmit entangled photons from the second entanglement source 422 or encoded photons from the second data transmission source 424 via the output of the second time gate 420 and the encryption channel 414.

[0095] When the quantum encrypted signal is received by the communication node 401, the first time gate 410 directs the received photon to either the first entanglement detector 402 or the first data transmission detector 408, according to the gating signal generated when the first entanglement source 404 generates an entangled pair (of which the first entangled photon is transmitted to the second communication node 403 for use as a gating signal).

[0096] Encryption channels 412 and 414 may be configured as optical fibers, as described herein. Similarly, communication line 416 is used to communicate bell state detection values ​​between communication nodes to ensure that the encryption channels remain secure.

[0097] Figure 5 shows a schematic diagram of a quantum cryptography system 500 for transmitting quantum encrypted signals, according to some embodiments of the technology described herein. The quantum cryptography system 500 includes a first entanglement source 502, shared quantum random number generators (QRNGs) 504, 540, time gates 506, 542, a data transmission source 508, a second entanglement source 510, Bell state value detectors (BSVs) 516, BSV 520, BSV 524, BSV 528, a first detector 512 associated with the shared QRNG 504, a second detector 514 associated with the BSV 516, an encryption channel 534, a first public channel 518, a second public channel 526, a third detector 522 associated with the BSV 524, a fourth detector 530 associated with the BSV 528, a fifth detector 536 associated with the BSV 520, and a sixth detector 538 associated with the shared QRNG 540, a time gate 542, a quantum cryptographic transmission 540, and entangled photons 534.

[0098] A first user 544 can use system 500 to send a secure message to a second user 546. To transmit a quantum encrypted transmission, the first entanglement source 502 generates an entangled photon pair including a first entangled photon 532 having a first wavelength and a second entangled photon having a second wavelength different from the first wavelength. The second entangled photon is received by a detector 512 associated with a shared quantum random number generator. The detector 512 is configured to detect the polarization state associated with the entangled photon 532.

[0099] The shared QRNG 504 generates random numbers based on the polarization detected by the detector 512. For example, the QRNG may randomly determine a binary value, for example, "0" or "1". The QRNG can generate random numbers by taking advantage of the random nature of the entanglement process. The polarization of entangled photons is random, and therefore the QRNG can generate random numbers based on the polarization of entangled photons 532 by assigning one of the random numbers to each polarization state. For example, if the photon has a first polarization, the QRNG may generate a value of "0", and if the photon has a second polarization orthogonal to the first polarization, the QRNG may generate a value of "1".

[0100] Random numbers generated by the shared QRNG 504 are provided to the time gate 506. In response to receiving a first random number, the time gate may select that light from the first input be output from the time gate to the encryption channel 534, and in response to receiving a second random number, it may select that light from the second input be output from the time gate. For example, if the number is "0", the time gate 506 may transmit encoded photons from the data encoder 508 to the encryption channel. If the number is "1", the time gate 506 may transmit entangled photons from the second entanglement source 510 to the encryption channel. As a result, an encrypted transmission 530 is generated with interleaved photons randomly determined based on the state of the entanglement source.

[0101] To decode this transmission, the time gate 542 receives a gating signal from the shared QRNG 540. The shared QRNG 540 receives the first entangled photon 534. Since the first and second entangled photons have a certain polarization relationship, the randomly interleaved photons can be separated to appropriate detectors by using the second entangled photon to encode the transmission signal using the time gate 506 and the first entangled photon to decode the transmission signal using the time gate 542. Then, by directing the entangled photons to the detector 530 associated with the BSV 528, the degree of entanglement between the third and fourth entangled photons can be determined, and it can be confirmed whether the photons remain entangled, and therefore whether the encryption channel is secure. BSV524 is configured to detect near-IR entangled photons generated by the second entanglement source 510, and BSV528 and BSV524, which detect the transmitted entangled photons, are communicably coupled via a non-quantum encrypted channel 526 to transmit the polarization measurement results performed at each detector used to determine the degree of entanglement.

[0102] Similarly, to verify the security of the gating signal generated from the first entanglement source 502, the polarization states of the second entangled photon 532 and the first entangled photon 532 are measured by using detector 514 associated with BSV 516 and detector 536 associated with BSV 520, respectively. BSV 516 and BSV 520 are communicably coupled via a non-quantum encrypted channel 518 to transmit the polarization measurement results performed by each detector used to determine the degree of entanglement.

[0103] In addition to generating a third entangled photon, the second entanglement source generates a fourth entangled photon, which is received by detector 522 to determine the Bell state value of the third entangled photon.

[0104] In the embodiment shown in Figure 5, the first entangled photon has a wavelength in the C band, the second entangled photon has a near-IR wavelength, the third entangled photon has a wavelength in the O band, and the fourth entangled photon has a near-IR wavelength.

[0105] In some embodiments, the interleaving between entangled photons and data-encoded photons involves alternating between each data-encoded packet (or subpacket) and the entangled photons. In some embodiments, chunks of data encoded in consecutive photons may be grouped together by entangled photons on both sides.

[0106] The various embodiments described above can be used individually, in combination, or in various arrangements not specifically described in the embodiments described above, and therefore their application is not limited to the details and arrangements of components shown in the above description or in the drawings. For example, an aspect described in one embodiment can be combined in any way with an aspect described in another embodiment.

[0107] While several aspects and embodiments of the technology described herein have been described, various modifications, variations, and improvements are readily conceivable to those skilled in the art. Such modifications, variations, and improvements are also intended to be included within the spirit and scope of the technology described herein. For example, those skilled in the art can readily conceive of various other means and / or structures for carrying out the functions described herein and / or obtaining one or more of the results and / or benefits, and each such modification and / or variation is also considered to be within the scope of the embodiments described herein. Those skilled in the art can recognize many equivalents to the particular embodiments described herein, or can verify them using mere routine experimentation. Therefore, the embodiments described above are presented only as examples, and embodiments of the present invention may be carried out in ways other than those specifically described, within the scope of the appended claims and their equivalents. In addition, any combination of two or more features, systems, articles, materials, kits, and / or methods described herein is within the scope of this disclosure, provided that such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

[0108] All definitions defined and used herein take precedence over dictionary definitions, definitions in literature incorporated by reference, and / or the common meaning of a defined term. As used herein and in the claims, “one” means “at least one” unless explicitly stated otherwise.

[0109] The terms "joined" or "connected" refer to elements or signals that are directly linked to each other or linked through intermediate components. Elements that are not "joined" or "connected" are "separated" or "disconnected."

[0110] The use of "between" in a coupled signal chain does not imply a specific direction for the flow of signals in the signal chain unless otherwise stated. For example, if element B is described as coupled between element A and element C in a signal chain, then unless otherwise stated, signals may flow from element A to element C via element B, and / or from element C to element A via element B.

[0111] As used herein and in the claims, the phrase "and / or" means "either or both" of the elements thus combined, i.e., elements that are sometimes conjunctive and sometimes disjunctive. Multiple elements listed in "and / or" are similarly interpreted as "one or more" of the elements thus combined. Other elements besides those specifically identified by the phrase "and / or" may be optionally present, whether related to or unrelated to those specifically identified elements. Thus, as a non-restrictive example, a reference to "A and / or B," when used in conjunction with open-ended language such as "equipped with," may in one embodiment refer to A only (optionally including elements other than B), in another embodiment refer to B only (optionally including elements other than A), and in yet another embodiment refer to both A and B (optionally including other elements).

[0112] As used herein and in the claims, the phrase “at least one” in reference to a list of one or more elements means at least one element selected from any one or more of the elements in the list of elements, and does not necessarily include at least one of all elements specifically enumerated in the list of elements, nor excludes any combination of elements in the list of elements. This definition also allows for the optional presence of elements other than those specifically identified in the list of elements to which the phrase “at least one” refers, whether or not they are related to those specifically identified elements. Therefore, as a non-restrictive example, “at least one of A and B” (equivalent to “at least one of A or B” or “at least one of A and / or B”) may mean, in one embodiment, at least one A, optionally including two or more A's, but no B (optionally including elements other than B); in another embodiment, at least one B, optionally including two or more B's, but no A (optionally including elements other than B); and in yet another embodiment, at least one A, optionally including two or more A's, and at least one B, optionally including two or more B's (optionally including other elements).

[0113] In the claims and specification, transitional phrases such as “equipped with,” “include,” “carry,” “possess,” “contain,” “accompany,” “hold,” and “composed of” should be understood as open-ended, meaning they include but are not limited to them. Only the transitional phrases “consist of” and “essentially consist of” are considered restrictive or semi-restrictive transitional phrases, respectively.

[0114] The terms “approximately” and “about” may be used to mean within ±20% of the target value in some embodiments, within ±10% of the target value in some embodiments, within ±5% of the target value in some embodiments, and within ±2% of the target value in some embodiments. The terms “approximately” and “about” may include the target value.

[0115] The use of sequential terms such as “first,” “second,” and “third” in a claim to modify a claim element does not, by itself, imply any priority, order, or sequence, or temporal order in which the actions of a method are performed for one claim element relative to another, but is merely used as a label to distinguish one claim element having a certain name from another element having the same name (not the use of sequential terms).

Claims

1. A system for encrypting data streams, An encrypted channel equipped with optical fiber, A first photon source configured to generate a first entangled photon pair comprising a first photon and a second photon during the operation of the system, wherein the first photon source is configured to output the first photon to the encryption channel and the second photon to the time gate, A second photon source configured to generate a second entangled photon pair comprising a third photon and a fourth photon during the operation of the system, wherein the second photon source is configured to output the third photon to the encryption channel and the fourth photon to the Bell state evaluator, The system comprises an optical modulator configured to modulate photons to generate encoded photons for transmitting the data stream, A system in which the time gate is configured to output the third photon or the encoded photon to the encryption channel for transmission of the data stream in response to the reception of the second photon.

2. The system according to claim 1, wherein the optical fiber of the encryption channel is configured to transmit light having a communication wavelength.

3. The system according to claim 2, wherein the optical fiber of the encryption channel is configured for bidirectional transmission.

4. The system according to claim 2, wherein the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

5. The system according to claim 1, wherein the time gate is an optical switch.

6. The system according to claim 1, wherein the first entanglement source is an atomic vapor cell-based entanglement source configured to generate entangled photon pairs having different wavelengths.

7. The system according to claim 6, wherein the first entangled photon of the entangled photon pair has a wavelength of 1200 to 1600 nm, and the second entangled photon of the entangled photon pair has a wavelength of 700 to 900 nm.

8. The system according to claim 7, wherein the first entangled photon has a wavelength of 1529 nm and the second entangled photon has a wavelength of 780 nm.

9. The system according to claim 1, wherein a quantum random number generator is used to generate a gating signal that controls the time gate.

10. The system according to claim 9, wherein the quantum random number generator is configured to detect light having polarization corresponding to the polarization state of the second photon in an entangled state.

11. The system according to claim 10, wherein the quantum random number generator is configured to transmit a control signal to the time gate based on the polarization state of the entangled second photon.

12. The system according to claim 11, wherein the time gate is configured to transmit light received from the optical modulator in response to the quantum random number generator detecting an entangled photon having a first polarization state, and is configured to transmit light received from the second entanglement source in response to the quantum random number generator detecting an entangled photon having a second polarization state orthogonal to the first polarization state.

13. The system according to claim 1, wherein the first entanglement light source is configured to generate a first entangled photon and a second entangled photon, the first entangled photon having a wavelength in the C band, and the second entanglement light source is configured to generate a third entangled photon and a fourth entangled photon, the third entangled photon having a wavelength in the O band.

14. The system according to claim 13, wherein the optical modulator is configured to modulate light having the same wavelength as the third entangled photon.

15. A system for reading encrypted signals from a communication data stream, An encrypted channel equipped with optical fiber, A first photon detector configured to receive a first entangled photon and generate a gating signal for controlling a time gate, wherein the time gate has two or more outputs, and the time gate is configured to control which of the two or more outputs transmits a signal received from the optical fiber at the input of the time gate, A second photon detector configured to receive the output from the first output of the time gate and determine the entangled state of photons, A third photon detector configured to receive the output from the second output of the time gate and detect photons corresponding to the data stream, A system equipped with these features.

16. The system according to claim 15, wherein the optical fiber of the encryption channel is configured to transmit light having a communication wavelength.

17. The system according to claim 16, wherein the optical fiber of the encryption channel is configured for bidirectional transmission.

18. The system according to claim 16, wherein the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

19. The system according to claim 15, wherein the time gate is an optical switch.

20. The system according to claim 15, wherein the first photon detector is coupled to a quantum random number generator configured to generate the gating signal for controlling the time gate based at least partially on the output of the photon detector.

21. The system according to claim 20, wherein the first photon detector is configured to detect light having polarization corresponding to the polarization state of the first entangled photon.

22. The system according to claim 21, wherein the quantum random number generator is configured to transmit a control signal to the time gate based on the polarization state of the second entangled photon.

23. The system according to claim 22, wherein the time gate is configured to transmit light received from the optical fiber to the second photon detector in response to the output of the quantum random number generator that has detected an entangled photon having a first polarization state, and is configured to transmit light received from the optical fiber to the third photon detector in response to the quantum random number generator detecting an entangled photon having a second polarization state, and the second polarization state is orthogonal to the first polarization state.

24. The system according to claim 15, further comprising an unencrypted channel.

25. The system according to claim 24, wherein the output of the second photon detector and the unencrypted channel are configured to verify the security of the encrypted channel.

26. A system for processing encrypted signals in a communication data stream, An encrypted channel equipped with optical fiber, A time gate having two or more inputs and two or more outputs for directing incident and outgoing photons, An optical modulator configured to modulate photons corresponding to a data stream to generate encoded photons for transmission, A first photon source configured to generate a first entangled photon pair, wherein the first photon source is configured to provide the first photon of the first entangled photon pair to the encryption channel and the second photon of the first entangled photon pair to the Bell state evaluator, A first photon detector configured to receive a first entangled photon and generate a gating signal for controlling the time gate, A system equipped with these features.

27. The system according to claim 26, wherein the optical fiber of the encryption channel is configured to transmit light having a communication wavelength.

28. The system according to claim 27, wherein the optical fiber of the encryption channel is configured for bidirectional transmission.

29. The system according to claim 27, wherein the optical fiber of the encryption channel is a first optical fiber configured for unidirectional transmission, the encryption channel includes one or more optical fibers, and the one or more optical fibers include a second optical fiber configured for unidirectional transmission in the direction opposite to the transmission direction of the first optical fiber.

30. The system according to claim 26, wherein the time gate is an optical switch.

31. The system according to claim 26, wherein the first photon detector is configured to detect light having polarization corresponding to the polarization state of the first entangled photon.

32. The system according to claim 31, wherein the first photon detector comprises a random number generator configured to transmit a control signal to the time gate based on the polarization state of the first entangled photon.

33. The system according to claim 32, wherein the time gate is configured to transmit light received from the optical modulator in response to the quantum random number generator detecting an entangled photon having a first polarization state, and is configured to transmit light received from the second entanglement source in response to the quantum random number generator detecting an entangled photon having a second polarization state orthogonal to the first polarization state.

34. The system according to claim 26, wherein the first photon source is configured to generate at least one entangled photon having the same wavelength as the photon generated by the optical modulator.

35. A method for encrypting communication optical signals using optical qubits for secure communication transmission, Generating a gating signal based on coherent photons received by the detector of a quantum random number generator. To generate a first dichromatic entangled pair comprising a first photon having a first wavelength configured for communication transmission and a second photon having a second wavelength different from the first wavelength, The process involves randomly selecting whether to transmit an encoded light source for data transmission or the first photon via an encrypted channel, and To detect the state of the second photon, A method for providing this.

36. The method according to claim 35, wherein the encryption channel is an optical fiber configured to transmit light having a communication wavelength.

37. The method according to claim 36, wherein selecting whether to transmit the light source encoded for data transmission or the first photon via the encryption channel controls which input of the optical switch is output by the optical switch.

38. The method according to claim 35, wherein generating the first two-color entangled pair includes generating an entangled photon pair using two-photon pumping of an atomic vapor cell.

39. The method according to claim 35, further comprising generating the coherent photons by generating a second dichromatic entanglement pair before generating the gating signal.

40. The method according to claim 35, wherein detecting the state of the second photon includes detecting the polarization state of the second photon.

41. Receiving instructions for the polarization state of the first photon via a non-quantum encryption channel, and To determine whether the polarization state of the first photon and the polarization state of the second photon indicate that the first photon and the second photon remained entangled even after the transmission of the first photon through the encryption channel. The method according to claim 40, further comprising:

42. An indication of when the first photon was received after transmission via the encryption channel is received via the non-quantum encryption channel, and Based on the received instruction regarding when the first photon was received after transmission through the encryption channel, and the instruction regarding when the first photon was transmitted through the encryption channel, it is determined whether the transmitted photon is missing. The method according to claim 35, further comprising:

43. A method for decoding an optical signal encoded using optical qubits to receive a data stream, Generating a gating signal based on coherent photons received by the detector of a quantum random number generator. The process of randomly selecting whether to transmit the received photons to the first photodetector or the second photodetector. To detect the photon corresponding to the entangled photon received by the first photodetector, To determine the entanglement state of the photons received by the first photodetector, and, To detect a second photon corresponding to the data stream received by the second photodetector, A method for providing this.

44. The method according to claim 43, wherein the coherent photons received by the detector are received from an encryption channel, and the encryption channel is an optical fiber configured to transmit light having a communication wavelength.

45. The method according to claim 43, wherein selecting whether to transmit the received photon to the first photodetector or to the second photodetector includes controlling which output of the optical switch is used to transmit the received photon.

46. The method according to claim 43, wherein detecting the photon corresponding to the entangled photon includes detecting a polarization state corresponding to the polarization state of the photon received by the first photodetector.

47. The method according to claim 46, further comprising transmitting an instruction on the polarization state of the photon received by the first photodetector via a non-quantum encryption channel.

48. The method according to claim 43, further comprising transmitting an instruction via a non-quantum encryption channel for when the photon will be received by the first photodetector.

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