JP2009088916A - Quantum authenticating method, quantum authentication system and quantum authenticating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform authentication without depositing a classic password with a certificate authority. <P>SOLUTION: One quantum bit stream of a pair of quantum bits being in a first Bell state is stored in a first quantum bit holder 1, the other quantum bit stream is stored in a second quantum bit holder 6, a converting part 21 converts a Bell state into a second Bell state being non-orthogonal state from the original Bell state by making a binary bit stream active to the one quantum bit stream, an inputting quantum password bit stream generating part 3 generates a quantum bit stream in a non-orthogonal state corresponding to a bit value of the binary bit stream, and performs unitary conversion processing of the converted quantum bit stream, the quantum bit stream in the non-orthogonal quantum state and the other quantum bit stream to thereby reproduce a pair of reproduced quantum bit streams in a third Bell state, a measuring part 71 measures whether the third Bell state coincides with the first Bell state, and when the measuring part 71 measures that they are coincident, an authenticating part 52 authenticates correctness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a quantum authentication method, a quantum authentication system, and a quantum authentication device. For example, an authentication method using a quantum password, an authentication system using a quantum password, a portable qubit holder, a qubit holder, and a bell state quantum Technology suitable for quantum authentication using a qubit pair such as a bit conversion device, an input quantum PIN number bit string generation device, a communication channel terminal, a key unlocking device, an authentication device, a key locking device, and an initialization device About.

  With the spread of the Internet and electronic commerce, advances in cryptographic techniques that can be used for maintaining confidentiality of communication, preventing falsification, and personal authentication are desired. Currently, the main authentication technology uses, for example, a classic password (authentication information) composed of 0 and 1 bit strings, personal information, etc., but classical authentication information can be easily duplicated. Because it is possible, it was vulnerable to various eavesdropping attacks.

Therefore, an encryption process based on computational security is applied to a communication path for transmitting authentication information, thereby preparing for an eavesdropping attack.
Such encryption technology is not proven to be secure at the principle level, but is based on computational security. However, in recent years, the idea of a quantum computer that far exceeds the performance of the classical computer has been proposed, and the security of the classical encryption technology based on computational security has been shaken.

In addition, the conventional encryption technology requires the authentication information, which is classical information, to be stored in the certification body. Therefore, if the authentication information is leaked due to fraud in the certification body or virus software, the security is maintained. Is difficult.
In this way, when the authentication information is classical information, it is possible to easily duplicate that information (replication possibility), and it is impossible to detect that it has been duplicated (duplication detection failure). In principle, information leakage cannot be prevented.

  In order to overcome these problems, biometric authentication using human fingerprints, veins, irises, faces, voices, and the like has recently been proposed. However, in principle, the person may be mistakenly recognized as not being the person himself / herself, or may be mistakenly recognized as being the person himself / herself despite being a different person. There is also a possibility that an artificial finger made of gelatin can pass through many fingerprint authentication systems, or an artificial iris made of paper can pass through an iris authentication system. Furthermore, biometric authentication may be unable to be authenticated due to injuries or illnesses, or may not be recognized due to the growth of the subject. In addition, since biological information is invariant throughout the life, safety issues have been pointed out, such as once biological information is replicated, its safety cannot be recovered for a lifetime.

Also in the authentication method using an authentication card or the like, since the certification authority still holds classical information, there is a possibility that information leakage from the certification authority may occur.
In addition, there are issues such as credit card skimming and counterfeiting. To deal with these problems, it is conceivable to use an IC card that is more difficult to duplicate than a magnetic information card. However, since classical information is also stored in the IC card, in principle, Copying authentication information cannot be prohibited, and encryption can be broken if the attacker's technology is high.

For this reason, quantum authentication technology has been proposed as an alternative to encryption technology using classical information.
For example, there is a technique called quantum key distribution for an eavesdropping attack on a communication path. Using this technique, it is possible to detect eavesdropping.
Further, quantum credit cards (quantum authentication cards) have been proposed for credit card skimming and counterfeiting. The information written in the quantum credit card is not duplicated in principle by the quantum duplication impossible theorem.

For example, the following Non-Patent Document 1 proposes a method of performing authentication by distributing and sharing a qubit pair having a entangled relationship between a quantum authentication card and an authentication authority.
Non-Patent Document 2 below proposes an authentication method using a quantum authentication card and a quantum ATM (Automated Teller Machine). In other words, the PIN code composed of classical information bits of 0 and 1 is stored in the bank, and the PIN code written in the orthogonal bell state is shared in quantum form between the quantum authentication card and the bank, and the quantum authentication card A method is disclosed in which a quantum code is measured at the time of authentication, a classic password is read, and the read password is compared with a classic password stored by a bank.

Further, Patent Document 1 below proposes a user recognition method using a quantum lock chip and a quantum authentication card.
In Patent Document 2 below, a quantum authentication card system using a quantum key is proposed.
JP 2003-283493 A JP 2004-56357 A “Quantum secure identification using entanglement and catalysis”, Howard N. Barnum, arXiv: quant-ph / 9910072. “Quantum non-demolition measurement of nonlocal variables and its application in quantum authentication”, Cuo-Ping Guo, Chuan-Feng Li and Guang-Can Guo, Physics Letters A286 (2001) 401-404.

However, the authentication method described above has the following problems.
For example, since the technique described in Non-Patent Document 1 relies on a quantum authentication card for authentication, an unauthorized person is authenticated when the quantum credit card is stolen.
On the other hand, since the techniques described in Non-Patent Document 2, Patent Document 1 and Patent Document 2 need to deposit a classic password in a bank, the password may be duplicated and leaked to the outside.

Further, in the technique described in Patent Document 1, the user needs to carry both the quantum lock chip and the quantum authentication card, and when both the quantum lock chip and the quantum authentication card are forged, There is a problem that safety is not guaranteed.
The present invention has been developed in view of the above-described problems, and an object of the present invention is to enable authentication without depositing at least a classic password to a certification authority. Another object of the present invention is to prevent unauthorized authentication.

  In addition, the present invention is not limited to the above-described object, and is an operational effect derived from each configuration shown in the best mode for carrying out the invention described later, and has an operational effect that cannot be obtained by conventional techniques. Can be positioned as one of the purposes.

In order to achieve the above object, the present invention uses the following quantum authentication method, quantum authentication system, quantum authentication device, and the like.
(1) That is, the authentication method using the quantum PIN of the present invention comprises a preparation step of preparing a pair of qubits consisting of N qubits and a qubit pair in a bell state, and a first quantum A storing step of storing one qubit string of the qubit pair in the bit holder; and a storing step of storing and storing the other qubit string of the qubit pair in the second qubit holder; And 0 and 1 for two qubit strings formed by the one qubit string stored in the first qubit holder and the other qubit string stored and stored in the second qubit holder, A conversion step for converting a portion corresponding to a portion having a true N-bit PIN number bit string value of 1 into a second bell state that is non-orthogonal to the original first bell state; According to the value of the N-bit code number bit string, a generation step of generating an input quantum code number bit string by replacing the input N-bit code number bit string with a non-orthogonal quantum state bit string, and the conversion step For the qubit string in the first qubit holder, the qubit string in the second qubit holder converted in the conversion step, and the input quantum password bit string generated in the generation step A reproduction step of performing unitary transformation processing to reproduce a reproduction qubit pair in a bell state, which is a pair of reproduction qubits composed of N reproduction qubits, and the reproduction quantum reproduced in the reproduction step. A measuring step for measuring whether the bell state of the bit pair matches the bell state of the qubit pair prepared in the preparing step; If it is determined in the step that they match, the use by the first qubit holder is authenticated, and if it does not match, the use by the first qubit holder is not valid. And an authentication step for authenticating.

  (2) Further, the authentication method using the quantum personal identification number of the present invention includes an authentication unit, a portable first qubit holder that stores a qubit, and stores and stores the qubit and stores it in the authentication unit. A second qubit holder capable of supplying the qubit being connected to the authentication unit and a quantum communication channel, and the portable first qubit holder is set to the portable first qubit holder. A communication channel terminal capable of transmitting a qubit stored in a qubit holder to the authentication unit, an input password qubit generation unit attached to the communication channel terminal, and a key unlocking unit In the authentication system, when performing authentication using the quantum personal identification number, a preparation step of preparing a qubit pair in a bell state, which is a pair of qubits composed of N qubits, and the portable first Qubit A storage step of storing one qubit string of the qubit pairs in a folder; and a storing step of storing and storing the other qubit string of the qubit pairs in the second qubit holder; , With respect to two qubit strings formed by the one qubit string stored in the portable first qubit holder and the other qubit string stored and stored in the second qubit holder, A conversion step of converting a portion corresponding to a portion of a true N-bit password number bit string consisting of 1 into a second bell state that is non-orthogonal to the original first bell state, and the input password number qubit The generating unit replaces the input N-bit PIN code bit sequence with a non-orthogonal quantum state quantum bit sequence according to the value of the input N-bit PIN code bit sequence, A generation step for generating a number bit string, and the portable first quantum bit holder storing the quantum bit string converted in the conversion step are set in the communication path terminal, and the conversion path terminal performs the conversion step. A transmitting step of transmitting the converted quantum bit string in the portable first quantum bit holder and the input quantum password bit string generated in the generating step to the authentication unit via the quantum communication path; In the key unlocking unit, the qubit string in the portable first qubit holder converted in the conversion step, the qubit string in the second qubit holder converted in the conversion step, and The input quantum PIN code bit string generated in the generation step is subjected to a unitary transformation process to form a reproduction quantum bit string pair consisting of N reproduction quantum bits. A reproduction step for reproducing the reproduction qubit pair in the bell state, and the bell state of the reproduction qubit pair reproduced in the reproduction step in the authentication unit is the bell of the qubit pair prepared in the preparation step. A measurement step for measuring whether or not the state matches, and if the measurement step determines that they match, the use by the portable first qubit holder is verified as valid, and if it does not match, the measurement is performed. If so, an authentication step of authenticating that the use by the portable first quantum bit holder is not valid is provided.

(3) Further, in the authentication method using the quantum password, when it is authenticated that the use is valid in the authentication step, the bell state of the reproduced qubit pair reproduced in the reproduction step is You may provide the reverse conversion step which performs reverse conversion which returns to the said 2nd bell state.
(4) Further, an erasing step of erasing the input quantum code number bit string may be provided after the inverse conversion step.

  (5) Moreover, the authentication system using the quantum PIN of the present invention further includes a pair of qubits made up of N qubits prepared in advance and one of the qubit pairs in the bell state. A first qubit holder for storing a qubit string, a second qubit holder for storing and storing the other qubit string of the qubit pair, and a first qubit holder. For the two qubit strings formed by the one qubit string and the other qubit string stored and stored in the second qubit holder, the value of the authentic N bit password bit string consisting of 0 and 1 is 1. A conversion unit that converts the portion corresponding to the portion into another second bell state that is non-orthogonal to the original first bell state, and the input N bit according to the value of the input N bit password bit string. In the first quantum bit holder converted by the conversion unit, the input quantum code number bit sequence generating unit for generating an input quantum code number bit sequence by replacing the code number bit sequence with a quantum bit sequence in a non-orthogonal quantum state , The quantum bit string in the second quantum bit holder converted by the conversion unit, and the input quantum PIN code bit string generated by the input quantum PIN bit string generation unit, A unitary transformation process, a key unlocking unit for reproducing a reproduction qubit pair in a bell state, which is a pair of reproduction qubits composed of N reproduction qubits, and the key unlocking unit reproduced by the key unlocking unit A measurement unit that measures whether or not the bell state of the reproduction qubit pair matches the bell state of the previously prepared qubit pair, and if the measurement unit measures the match, the first amount With the use by the bit holder is authenticated as a legitimate, if it is determined that they do not match, and an authentication unit for use by the first qubit holder is authenticated not authentic.

  (6) Further, the authentication system using the quantum PIN of the present invention is a pair of qubits composed of N qubits prepared in advance and is one of the qubit pairs in the bell state. A portable first qubit holder, a second qubit holder that stores and stores the other qubit string of the qubit pair, and a portable first qubit holder. For the two qubit strings formed by the one qubit string and the other qubit string stored and stored in the second qubit holder, the value of the authentic N bit password bit string consisting of 0 and 1 is A conversion unit that converts a portion corresponding to 1 into another second bell state that is non-orthogonal to the original first bell state, and the input unit according to the value of the input N-bit PIN code bit string. An input quantum code number bit string generation unit for generating a quantum code number bit string for input by replacing the bit code number bit string with a quantum bit string in a non-orthogonal quantum state, and the portable type storing the quantum bit string converted by the conversion unit By setting the first quantum bit holder, quantum communication is performed between the quantum bit string in the portable first quantum bit holder and the input quantum code number bit string generated by the input quantum code number bit string generation unit. A communication channel terminal for transmitting via a channel; a qubit string in the portable first qubit holder connected to the communication channel terminal via the quantum communication channel and converted by the conversion unit; The quantum bit string in the second quantum bit holder converted by the conversion unit, and the input quantum PIN code bit string generated by the input quantum PIN bit string generation unit Then, a unitary conversion process is performed, and a key unlocking unit that reproduces a reproduction qubit pair in a bell state, which is a pair of reproduction qubits composed of N reproduction qubits, and reproduction by the key unlocking unit A measurement unit that measures whether the bell state of the reproduced qubit pair is identical to the bell state of the previously prepared qubit pair; An authentication unit that authenticates that the use by the first type quantum bit holder is valid, and authenticates that the use by the portable first quantum bit holder is not valid if it is determined that the use does not match.

(7) In the authentication system using the quantum password, when the authentication unit authenticates use, the reproduced qubit in the bell state reproduced by the key unlocking unit You may provide the key lock part which performs reverse conversion which returns a pair bell state to the said 2nd bell state.
(8) Further, an initialization unit for erasing the input quantum code number bit string may be provided.
(9) The qubit holder of the present invention is the first qubit holder used in the authentication system using the quantum code number, and is a pair of qubits composed of N qubits. In addition, it stores one qubit string in the qubit pair in the bell state and has a storage unit that stores the qubit string converted by the conversion unit.

(10) Furthermore, the qubit holder of the present invention is the second qubit holder used in the authentication system using the quantum password, wherein the qubit pair of the qubit pair is the other qubit string. A storage unit for storing and storing is provided.
(11) Moreover, the bell state qubit conversion device of the present invention includes the conversion unit used in the authentication system using the quantum password.

(12) Further, an input quantum PIN number bit string generation device according to the present invention includes the input quantum PIN number bit string generation unit used in the authentication system using the quantum password.
(13) Further, the communication path terminal of the present invention is the communication path terminal used in the authentication system using the quantum PIN code, and stores the qubit string converted by the conversion unit. By setting one quantum bit holder, the quantum bit string in the first quantum bit holder and the input quantum password bit string generated by the input quantum password bit string generation unit are connected to the quantum channel. Via a transmission unit.

(14) Furthermore, the key unlocking device of the present invention has the key unlocking unit used in the authentication system using the quantum personal identification number.
(15) Moreover, the authentication apparatus of this invention has said measurement part and authentication part used for the authentication system using the said quantum PIN code.
(16) Furthermore, the key locking device of the present invention has the key locking unit used in the authentication system using the quantum personal identification number.

(17) Moreover, the initialization apparatus of this invention has the said initialization part used for the authentication system using the said quantum PIN code.
(18) Further, in the quantum authentication method of the present invention, one qubit string of a qubit pair consisting of N qubits in a first bell state is used as the first qubit holder. Storing the other quantum bit string in the second quantum bit holder, and applying a binary bit string consisting of a combination of 0 and 1 to the one quantum bit string in the first quantum bit holder. A step of setting the bell state of the qubit corresponding to the portion of the binary bit string having a value of 1 to a second bell state that is non-orthogonal to the original bell state, and a qubit string subjected to the operation of the binary bit string Is obtained from the first quantum bit holder, and the input of the binary bit string is received to generate a non-orthogonal quantum state quantum bit string corresponding to the bit value. A unitary transformation for the step, the qubit string subjected to the action of the obtained binary bit string, the generated qubit string in the non-orthogonal quantum state, and the other qubit string in the second qubit holder Performing a process of reproducing a reproduction qubit pair of N reproduction qubits and a reproduction qubit pair in a third bell state, wherein the third bell state is the first bell state; Measuring whether it matches the bell state, and authenticating use by the first qubit holder when it is determined to match.

(19) Here, the binary bit string may be a bit string corresponding to a password determined by a user of the first quantum bit holder.
(20) The binary bit string may be a bit string corresponding to biometric information of a user of the first quantum bit holder.
(21) Further, the quantum authentication device of the present invention is a combination of 0 and 1 with respect to one qubit string of a qubit pair consisting of N qubits and being in the first bell state. A qubit sequence in which a qubit bell state corresponding to a portion where the value of the binary bit sequence is 1 is made into a second bell state that is non-orthogonal to the original bell state by operating a binary bit sequence consisting of An acquisition means for acquiring from a qubit holder; a second qubit holder for storing the other qubit string in the qubit pair in the first bell state; and a bit received upon input of the binary bit string Generation means for generating a non-orthogonal quantum state quantum bit string according to a value, a quantum bit string acquired by the acquisition means, and a non-orthogonal quantum state quantum bit string generated by the generation means A unitary transformation process is performed on the other quantum bit string in the second quantum bit holder to form a pair of reproduced qubits consisting of N reproduced qubits and in the third bell state. A reproduction means for reproducing a reproduction qubit pair; a measurement means for measuring whether or not the third bell state matches the first bell state; and Authentication means for authenticating use by the first quantum bit holder.

According to the present invention, at least one of the following effects or advantages can be obtained.
(1) Since the authentication side does not hold a secret code or the like that is classical information, it is possible to prevent leakage of information necessary for authentication and to realize a robust authentication system.
(2) Further, since both the qubit string stored in the qubit holder and the input quantum PIN code bit string are required for authentication, even if the qubit holder is stolen, unauthorized authentication can be prevented. .

(3) Furthermore, if the input quantum PIN number bit string is deleted after authentication, the authentication side does not hold the information used for authentication, so that further robustness can be obtained.
(4) In addition, since the input quantum PIN code bit string has two non-orthogonal quantum states, it is not duplicated in principle. Thereby, unauthorized authentication can be prevented.

Embodiments of the present invention will be described below with reference to the drawings. However, it goes without saying that the present invention is not limited to the embodiments described below, and can be variously modified and implemented without departing from the spirit of the present invention.
[1] Premise Technology (1.1) Quantum Bit A quantum state consists of several basic states and their superposition states. Mathematically, the fundamental state corresponds to a vector space basis, and the superposition state corresponds to their linear combination.

The basic unit of classical information is a bit having a state of either 0 or 1 (classical bit value) at a certain point in time, whereas at a certain point in time, “| 0>” and “| A physical system having a basic state of “1>” is called a qubit. For the qubit, spin, which is the rotation of electrons, nuclei, and photons, and other two-level quantum mechanical systems are used.
The conventional classical bit value can be associated with the basic states of “| 0>” and “| 1>”, which are one of the quantum states in the qubit. In addition, it is possible to take a superposition state of “| 0>” and “| 1>”. For this reason, qubits can be expressed in association with information in various forms as compared to classical physical systems such as classical bit values.

However, only the state that is orthogonal, such as the basic states of “| 0>” and “| 1>”, is a state in which the quantum state can be reliably identified, and the amount of information that can be stored in one qubit Corresponds to 1 bit.
In addition, qubits have features that are not found in classical physical systems, such as wiretapping detection based on the uncertainty principle of quantum mechanics and the inability to replicate quantum states. There is a big effect.

  For example, in the nuclear spin qubit system, which is one of the qubit systems that realize the qubit, a quantum dot (quantum well) is formed in a semiconductor such as gallium arsenide (GaAs) to bind the electrons, Using the interaction between the system and the Ga and As nuclear spins, the nuclear spins are controlled in correspondence with qubits. Such technologies are mainly studied as part of quantum computer technology development (G. Yusa, K. Muraki, K. Takashina, K. Hashimoto and Y. Hirayama, Controlled multiple quantum coherences of nuclear spins in a nanometre-scale device, Nature 434, 1001 (2005). Reference URL: Nippon Telegraph and Telephone Corporation, Japan Science and Technology Agency http://www.ntt.co.jp/news/news05/0504/050420.html).

In addition to the above-mentioned nuclear spin qubit system, developments such as photon systems, superconducting quantum interferometers (SQUIDs), electron systems in quantum dots (quantum wells), charged particle systems trapped in microcavities, etc. are progressing. Yes.
Up to this point, the fixed basic state has been described. However, the selection of the basic state is arbitrary. For example, in the case of a spin system, a set of basic states is determined for components in each direction of spin. In general, the selected direction may be referred to as the z-axis direction. In this case, several sets of basic states corresponding to different components such as the x-axis direction and the y-axis direction are used in parallel. There is also.

(1.2) Unitary transformation As described in (1.1) above, any quantum information (classical bit value) can be represented by a bit string of 0s and 1s. Information can be expressed as a qubit string.
One of information processing that can be physically executed for quantum information represented by a qubit string is unitary transformation using the basic principle of quantum mechanics (Schrödinger equation).

  One feature of this unitary transformation is that any arbitrary unitary transformation can be composed of a combination of a unitary gate acting on one qubit and a control knot gate (hereinafter referred to as CNOT gate) acting on two qubits. (A. Barenco, CH Bennett, R. Cleve, DP DiVincenzo, N. Margolus, P. Shor, T. Sleator, JA Smolin and H. Weinfurter, Elementary gates for quantum computation, Physical Review A 52, 3457 (1995).) Is theoretically known by. From this, if the basic gate (one qubit unitary gate, CNOT gate) can be mounted, any unitary conversion can be physically mounted.

Here, a unitary gate acting on one qubit can be easily realized by applying a predetermined magnetic field in a certain direction for a predetermined time in a qubit system constituted by spins and electrons of nuclei, for example. Such a unitary gate is represented by a quantum circuit diagram as shown in FIG.
In the quantum circuit diagram of FIG. 1, one qubit is described by one line, and a unitary gate acting on one qubit is expressed by a square or a circle arranged in the middle of the line.

In contrast, the CNOT gate is a two-qubit gate composed of a control qubit and a target qubit. Such a CNOT gate is represented by a quantum circuit diagram as shown in FIG.
In the quantum circuit diagram of FIG. 2, each qubit is represented by a line, and the control qubit is marked with a black circle, while the target qubit is marked with a plus sign in a white circle.

Next, the operation of the CNOT gate will be described with reference to FIGS.
For example, when the quantum state “| 0>” corresponding to the bit value “0” is input to the CNOT gate as the control qubit, the states of the control qubit and the target qubit are output unchanged. On the other hand, when the quantum state “| 1>” corresponding to the bit value “1” is input to the control qubit, the state of the target qubit is inverted and output.

  For example, as shown in FIG. 3, when the input state of the control qubit is “| 0>” and the input state of the target qubit is “| 0>”, the output remains “| 0>”. The control qubit is also “| 0>”. Also, as shown in FIG. 4, if the input state of the target qubit is “| 1>”, its output also remains “| 1>”.

  On the other hand, for example, as shown in FIG. 5, when the input state of the control qubit is “| 1>” and the input state of the target qubit is “| 0>”, the output of the control qubit is Although “| 1>” remains, the output of the target qubit is “| 1>”. Further, as shown in FIG. 6, if the input state of the target qubit is “| 1>”, the output is “| 0>”.

  Such CNOT gates are already implemented in various qubit systems. For example, in a qubit system composed of nuclear spins and electron spins, one qubit is obtained by using the Heisenberg exchange interaction, which is a basic interaction that aligns the directions of two spins under a controlled external magnetic field. It is known that a CNOT gate can be implemented together with a unitary gate. It is also known that the CNOT gate can be realized by a quantum dot (quantum well) system, a superconducting charge qubit system, or the like.

(1.3) Generation of entanglement (quantum entanglement) In the above-described two-qubit system, two qubits can have a relationship called entanglement (quantum entanglement).
For example, in a two-qubit system, a bell state indicated by “| +>” is called a maximum quantum entangled state.

For a pair of qubits in such a maximum entangled state, the measurement (observation) result of each qubit shows the strongest correlation, but what kind of measurement result is obtained when only one qubit is measured Is completely unknown.
For example, when a qubit pair of the bell state “| +>” given by the following equation (1) is observed by a predetermined observation method, if the quantum state of one qubit is observed as “| 0>” The quantum state of the other qubit is always observed as “| 0>”. Similarly, if the quantum state of one qubit is observed as “| 1>”, the quantum state of the other qubit is always observed as “| 1>”.

However, which case occurs is not determined at all. The probability that “| 0>” is observed is 50%, and the probability that “| 1>” is observed is also 50%.
Further, such a correlation appears in exactly the same manner for all sets of basic states, regardless of how to select a set of basic states that define a qubit (for example, how to select a spin direction). This is a characteristic unique to entanglement in qubits and cannot be realized by classical correlation.

When the above feature is applied to the communication field, it can play the role of tally (authentication information) using the strong correlation between the measurement results of 2 qubits. In addition, since only one qubit is meaningless as information, there is no damage even if it is stolen or leaked, so that it can be used as an authentication technique with high security.
The entangled state including the maximum entangled state as described above can be generated by using the 1-qubit unitary gate and the CNOT gate described in (1.2) above in any qubit system. .

  Recently, it has been reported that two photons in a entangled state are generated by irradiating a semiconductor with a laser in a photon qubit system (K. Edamatsu, G. Oohata, R. Shimizu). and T. Itoh, Generation of ultraviolet entangled photons in a semiconductor, Nature 431, 167 (2004). Reference URL: http://www.jst.go.jp/pr/info/info109/index.html). Photon-based quantum entanglement can be transferred to a nuclear spin qubit using an interface technique described in (1.4), and is expected as a quantum entanglement technique that can also be used in the present invention.

In addition, although it is an indispensable technique for the implementation | achievement of a quantum computer, it is known that generation | occurrence | production of the entanglement between the multiquantum bit strings which consist of several quantum bit strings larger than 2 is very difficult. Since the present invention only needs to control the entanglement between a pair of qubit strings, there is no difficulty associated with entanglement control between multiple qubits.
(1.4) Interface and transmission For the qubit system used for quantum information transmission to a remote place, photons that can be propagated by optical fiber are currently promising candidates.

  Quantum states stored in qubits (quantum card memory) composed of semiconductor nuclear spins, etc., are communicated remotely, and conversely quantum information sent from a distance is stored in the quantum card memory. Requires an interface technology that moves information from nuclear spins to electronic systems and from electronic systems to photonic systems (or vice versa), and this is also actively developed and researched.

  Information transmission from the nuclear spin to the electron system is being studied by Heisenberg exchange interaction between the spins. When transferring information from a quantum dot electron system to a photon, the g factor that controls the spin degree of freedom of a single electron Active research and development based on research on engineering and rapid dissociation of electron-hole pairs has become possible (H. Kosaka, H. Kiselev, AA Baron, FA Kim, KW Yablonovitch, Electron factor engineering in III-V semiconductors for quantum communications, Electronics Letters 37, 464 (2001) .Reference URL: Strategic Creation Research Promotion Project, Japan Science and Technology Agency, Creation of New Technology for Realizing Quantum Information Processing System http: // www .jst.go.jp / kisoken / crest / intro / kadai / h1501.html).

[2] Description of Embodiment An embodiment of the present invention will be described below with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not clearly shown in the embodiment described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention.

  FIG. 7 is a block diagram showing the configuration of a quantum authentication system according to an embodiment of the present invention. For example, the quantum authentication system includes a quantum authentication card 1 having a storage unit 9, a password writing device 2, a password. An automatic terminal 3 having a qubit string generation device 10, a quantum communication channel 4, an open / close lock device 5, an authentication qubit holder 6 having a storage unit 11, a bell measurement device 7, and a password qubit initial And the conversion device 8 are provided.

  Here, the quantum authentication card 1 is a portable qubit holder (first qubit holder) having a function of storing qubits. The quantum authentication card 1 of this example is a pair of qubits made up of N (N is a natural number, N = 4 in the example of FIG. 7) qubits prepared in advance on the certification authority side, and the bell state “ It has a storage unit 9 that can store one of the qubit pairs in | +> ”and the qubit string (card qubit string) converted by the personal identification number writing device 2. As the storage unit 9, for example, a quantum memory capable of storing quantum bits is used.

  The personal identification number writing device (bell state qubit converting device) 2 converts the bell state of the qubit into another bell state. The PIN code writing device 2 of the present example includes a card qubit string stored in the quantum authentication card 1 and the other qubit string of the prepared qubit pairs stored and stored in the authentication qubit holder 6. An arbitrary genuine N-bit code number bit string (binary bit string) composed of a combination of 0 and 1 set by the user of the quantum authentication card 1 is applied to the two-qubit string formed by the (verification quantum bit string). The conversion unit 21 converts the bell state of each qubit corresponding to the portion of the binary bit string having a value of “1” into a second bell state that is non-orthogonal to the original bell state (first bell state). It has a function.

For the above conversion, for example, a predetermined unitary conversion (hereinafter referred to as unitary conversion R) as described in (1.2) above is used.
Hereinafter, for the sake of simplicity, for example, the binary bit string is represented as “0101”, the first bell state quantum bits are represented by white circles, and the second bell state quantum bits are represented by black circles.
At this time, the quantum bit string stored in the quantum authentication card 1 is represented by the personal identification number writing device 2 as a quantum bit string as shown in the storage unit 9 in FIG.

  Further, since the card quantum bit string and the verification quantum bit string have a relation of the maximum quantum entangled state of the bell state “| +>” in advance, the card quantum bit string is unitary with respect to the card quantum bit string stored in the quantum authentication card 1. When the conversion R is performed, the synthesis system of the card quantum bit sequence and the verification quantum bit sequence changes to different bell states. However, this theoretically changes to the same state as when the unitary transformation R is applied to the collation quantum bit string. As a result, the unitary transformation R is remotely applied to the verification qubit string stored and stored in the authentication qubit holder 6.

Therefore, the verification qubit string stored and stored in the storage and storage unit 11 of the authentication qubit holder 6 is also represented by a qubit string as shown in the storage and storage unit 11 in FIG.
In addition, the user can change the personal identification number as appropriate using the personal identification number writing device 2.
The binary bit string may be a bit string corresponding to the user's biometric information (physical feature information such as fingerprints, irises of the eyeballs, voiceprints, etc.) in addition to the password determined by the user. In this way, the possibility that the binary bit string is duplicated can be made extremely low. Further, since the user does not need to store or write down the binary bit string, security and convenience are improved. However, when the binary bit string is a bit string corresponding to the user's biometric information, the biometric information may be duplicated. Therefore, the user can arbitrarily set and store the binary bit string. Is safer.

  When the quantum authentication card 1 that stores the card quantum bit string is set, the automatic terminal (communication channel terminal) 3 acquires the card quantum bit string from the quantum authentication card 1 and generates the card quantum bit string and the password quantum bit string. It has a function as a transmission unit 31 that transmits the personal identification number quantum bit string (input quantum personal identification number bit string) generated by the apparatus 10 to the certification authority side via the quantum communication path 4.

  Here, the personal identification number quantum bit string generation device (input quantum personal identification number bit string generation unit) 10 receives the input of the personal identification number bit string (binary bit string) set by the user, and the binary bit string (in this example, “ [0101]) is replaced with two kinds of non-orthogonal quantum states as will be described later, thereby providing a function as a generating means for generating a password quantum bit string corresponding to the binary bit string. Since the input quantum code number bit string is in two non-orthogonal quantum states, it is not duplicated in principle, and unauthorized authentication can be prevented. In the figure, the code number quantum bit string corresponding to the binary bit “0101” is represented by a white circle and a shaded circle.

The quantum communication path 4 is a quantum communication path that connects the automatic terminal 3 and the opening / closing lock device 5. The quantum communication channel 4 of this example has a function of transmitting a card quantum bit string stored in the quantum authentication card 1 set in the automatic terminal 3 and transmitting a password quantum bit string. The technique described in 1.4) is used.
In other words, the automatic terminal 3 and the quantum communication channel 4 are a pair of qubits composed of N qubits prepared by the certification authority side, and one of the qubit pairs in the first bell state is connected to the qubit string. On the other hand, it functions as an acquisition unit that acquires from the quantum authentication card 1 a card quantum bit string that has been subjected to unitary transformation R by applying the binary bit string.

The authentication qubit holder 6 is a second qubit holder having a function of storing and storing qubits. The authentication qubit holder 6 of this example has a storage unit 11 that stores and stores the verification qubit string.
The opening / closing lock device (key unlocking device, key locking device, and authentication device) 5 includes a card qubit sequence and a verification qubit sequence that have been subjected to unitary conversion R by the personal identification number writing device 2, and an automatic terminal 3. A predetermined unitary transformation different from the unitary transformation R (hereinafter referred to as a unitary transformation U) is applied to the code number quantum bit sequence of N, so that a reproduction quantum bit sequence composed of N reproduction quantum bits can be obtained. It has a function of reproducing a pair of reproduced qubits that are in the third bell state.

  That is, the open / close lock device 5 of the present example is connected to the automatic terminal 3 via the quantum communication channel 4, and the second-bell-state card quantum bit string stored in the quantum authentication card 1 and the authentication A pair of regenerated qubits composed of N regenerated qubits is obtained by performing unitary transformation processing U on the second-bell state qubits stored in the qubit holder 6 and the password qubits. In addition, it also has a function as a key unlocking unit (reproducing means) 51 for reproducing the reproduced qubit pair in the third bell state.

Further, the bell measuring device 7 determines that the bell state (third bell state) of the regenerated qubit pair regenerated by the open / close lock device 5 is the original bell state of the qubit pair prepared in advance on the certification authority side ( It has a function as a measuring unit (measuring means) 71 that measures whether or not it matches the first bell state.
Further, the opening / closing lock device 5 uses the bell measuring device 7 to detect the bell state (third bell state) of the regenerated qubit pair and the original bell state (first state) of the qubit pair prepared in advance on the certification authority side. If it is determined that the use of the quantum authentication card 1 is valid, it is authenticated (determined) that the use by the quantum authentication card 1 is valid. A function as an authentication unit (authentication unit) 52 that performs authentication (determination) is also provided.

In addition, when the unlocking / locking device 5 authenticates that the use by the quantum authentication card 1 is valid, the open / close lock device 5 determines the bell state (third bell state) of the reproduction qubit pair based on the password qubit string, It also has a function as a key locking unit 53 that performs reverse conversion (reverse unitary conversion U ⁻¹ ) to return to the second bell state.
The personal identification number quantum bit string initialization device (initialization device) 8 has a function as an initialization unit 81 that erases the personal identification number quantum bit string transmitted from the personal identification number quantum bit string generation device 10 via the quantum communication channel 4. . Thereby, since the information used for authentication is not held, there is no outflow of information that can be used illegally, and a robust authentication system can be realized.

By configuring the quantum authentication system as described above, the following operation can be realized.
That is, the certification authority side prepares a qubit pair that is a pair of qubits composed of N qubits in advance and is in the bell state (first bell state) (preparation step), and the user of the quantum authentication card 1 One qubit pair of the qubit pairs is stored in the quantum authentication card 1 (storage step), while the certification authority side stores the other qubit string in the qubit pair in the authentication qubit holder 6. Store (store step). Note that the entanglement generation technique (1.3) is used to generate the qubit pair in the bell state.

  Then, the user determines an N-bit personal identification number bit string composed of 0 and 1 (for example, a binary bit string having a value of “0101”), and is stored in the quantum authentication card 1 by the personal identification number writing device 2. By applying a unitary transformation R to the portion of the qubit string where the value of the code number bit string is “1”, one qubit string of the qubit pair is returned to the original bell state (first bell state). ) Is converted into a card quantum bit string having another bell state (second bell state) that is non-orthogonal (conversion step). At this time, the qubit string stored in and stored in the authentication qubit holder 6 that has a entanglement relationship with the card qubit string is also converted into a collation qubit string by receiving the same conversion action.

Next, the user sets the quantum authentication card 1 in the automatic terminal 3 and inputs the personal identification number bit string, and generates a personal identification number quantum bit string corresponding to the personal identification number bit string in the automatic terminal 3 (generation step). The password quantum bit string and the card quantum bit string are transmitted to the open / close lock device 5 via the quantum communication channel 4 (transmission step).
On the certification authority side, the open / close lock device 5 converts the password qubit string and the converted card qubit string transmitted from the automatic terminal 3, and the collation qubit string stored and stored in the authentication qubit holder 6. On the other hand, by performing a predetermined unitary transformation U, a reproduction qubit pair which is a pair of reproduction qubits composed of N reproduction qubits and is in the third bell state is reproduced (reproduction step).

  Then, the bell measuring device 7 measures whether or not each bell state (third bell state) and the original bell state (first bell state) of the reproduction qubit pair match (measurement step), If it is measured that they match, it is authenticated that the use of the quantum authentication card 1 is valid. On the other hand, if it is determined that they do not match, it is determined that the use of the quantum authentication card 1 is illegal (authentication step). Note that the above measurement (bell measurement) measures whether or not two states match, and does not measure (observe) individual qubits. For this reason, authentication can be performed without affecting the state of the qubit.

When it is authenticated that the use of the quantum authentication card 1 is valid, the certification authority side uses the open / close lock device 5 to perform an inverse unitary transformation U ⁻¹ that returns the bell state of the regenerated qubit pair to the second bell state. This is performed (inverse conversion step), and the inversely converted qubit pair is returned to the quantum authentication card 1 and the authentication qubit holder 6 respectively, and the password qubit string is erased (erase step).

This quantum authentication system operates as described above, so that the certification authority side does not hold a secret number or the like, which is classical information, so that it is possible to prevent authentication information from leaking, and a robust authentication system Can be realized.
In addition, since the authentication operation requires both a card quantum bit string and a password quantum bit string stored in the quantum authentication card 1, even if the quantum authentication card 1 is stolen, unauthorized authentication (spoofing, etc.) is prevented. can do.

(Application example of this quantum authentication system)
Below, the application example of this quantum authentication system is demonstrated using FIGS. 8-20.
In this example, it is assumed that a user receives cash from an ATM (Automated Teller Machine) 3 after being authenticated by a bank (certification organization).
First, as a preparation stage, as shown in FIG. 8, the bank prepares N (for example, N = 4) qubit pairs in the bell state “| +>” defined by Expression (1) for each user. Keep it. For this generation, for example, the entanglement unitary operator which is the technique of (1.3) above is used.

Next, as shown in FIG. 9, the user stores one qubit string in the qubit pair in the quantum credit card (quantum authentication card) 1. For example, when the qubit uses a semiconductor nuclear spin, the quantum credit card 1 stores N nuclear spins.
On the other hand, the bank stores and stores the other qubit string of the qubit pair in the authentication qubit holder 6 for authentication. For example, the bank stores and stores the authentication quantum bit holder 6 in a storage. As in the storage procedure for the quantum credit card 1, for example, a method of storing N nuclear spins is used for this storage and storage.

Next, as shown in FIG. 10, the user defines an N-bit personal identification number bit string (for example, “0101”) composed of 0 and 1. This personal identification number bit string is kept secret by the user himself.
Then, as shown in FIG. 11, the user uses the personal identification number writing device 2 to generate two qubits expressed by the equation (2) formed by the qubits stored in the quantum credit card 1 and the authentication qubit holder 6. The part where the value of the code number bit string is “1” with respect to the state string is non-orthogonal to the bell state of the above expression (1), and the following expressions (3), (4) and (5) The unitary transformation R defined by the equations (6) and (7) is applied in order to convert to another bell state “| ξ>” defined by

  As a result, the bell state “| +>” shown in the equation (1) is converted into the bell state “| ξ>” shown in the above equation (3) by the following equation (8).

  For example, when the personal identification number bit string is “0101”, the quantum bits stored in the quantum credit card 1 and the authentication quantum bit holder 6 at this point are in the state shown by the following equation (9). Yes. Each qubit sequence at this time is referred to as a card qubit sequence and a verification qubit sequence, respectively.

  Next, as shown in FIG. 12, in the ATM 3, the user uses the password quantum bit string generation device 10 to define the quantum state and quantum state “| 0>” defined by the following equations (10) and (11). A code number quantum bit string corresponding to the code number bit string is generated, which is composed of two types of non-orthogonal quantum states (see equation (12)).

  For example, the portion where the value of the code number bit string (“0101”) is “0” is replaced with the quantum state “| 0>”, and the portion where the value of the code number bit string is “1” is replaced with the quantum state “| By replacing with “α>”, the personal identification number quantum bit string shown in Expression (13) is generated.

Then, a card quantum bit string (hereinafter simply referred to as a card quantum bit string K) stored in the quantum credit card 1 and a password quantum bit string “| 0> | α> | 0> | α> ”(hereinafter simply referred to as a personal identification number quantum bit string W) is transmitted to the bank side via the quantum communication path 4.
In the bank, as shown in FIG. 13, in addition to the card qubit string K and the personal identification number qubit string W from the ATM 3, a verification qubit string (hereinafter simply referred to as a verification qubit string) stored in the authentication qubit holder 6 M) is input to the open / close lock device 5. Here, the state sequence formed by the synthesis system of the card quantum bit sequence K and the verification quantum bit sequence M is given by “| +> | ξ> | +> | ξ>”. The state sequence formed by the synthesis system of the password quantum bit sequence W, the card quantum bit sequence K, and the verification quantum bit sequence M is “| 0> | +> | α> | ξ> | 0> | +> | α> | ξ > ”.

  Next, as shown in FIG. 14, the bank operates the unitary transformation U defined by the following formulas (14) to (25) by the opening and closing lock device 5, thereby causing the regenerated quantum in the third bell state. Play bit pairs.

The unitary transformation U is realized by a quantum circuit as shown in FIG. 15, for example.
In FIG. 15, T, V, and S are defined by the following equations (26) to (28), respectively, and T ^† , V ^†, and S ^† are Hermitian conjugates of T, V, and S, respectively. Represents a relationship.

  That is, the unitary transformation U can be expressed by Equation (29).

  The unitary transformation U as described above converts the input given by the equation (30) as shown in the equation (31), while the input given by the equation (32) gives the equation (33). ) And the state defined by the equation (34).

  Therefore, the personal identification number qubit string W is output in two non-orthogonal states represented by Expression (35). In this example, for example, it is output in a state represented by Expression (36).

Even if the bank measures (observes) the quantum bit string in the quantum state represented by the above equation (36), the code number bit string “0101” as the original classical information is accurately set due to its non-orthogonality. Cannot read. For this reason, there is no possibility that information related to the code number bit string is known to users other than the user.
Further, as described above, the bell state of the reproduction qubit pair reproduced by the unitary transformation U becomes the bell state shown in Expression (37) when the password number bit string input to the ATM 3 by the user is correct.

What is important here is that the output quantum state of 2 qubits (card qubit string K and collation qubit string M) is used by the above-mentioned quantum credit card 1 if the input of the code number bit string by the user is correct, that is, by a valid user. If it is, the bell state “| +>” shown in the equation (1) is always obtained.
Next, as shown in FIG. 16, the bank inputs the reproduced qubit pair to the bell measuring device 7, and each bell state (third bell state) and the original bell state (first bell state) of the reproduced qubit pair. (State) and whether each match.

This measurement result is notified to the opening / closing lock device 5 and when it is determined that they match, the use of the quantum credit card 1 is authenticated and the subsequent procedure (cash delivery etc.) is continued, but they do not match. In such a case, it is determined that the use of the quantum credit card 1 is inappropriate, and the subsequent procedure is stopped.
Thereby, the bank can confirm that the authentication applicant is a valid user without knowing information related to the user's personal identification number bit string.

  If it is determined that the user is a valid user, the bell state (third bell state) of the reproduction qubit pair obtained by the bell measurement is all determined to be the state of the expression (1), and the bell The state after measurement is unchanged. On the other hand, if the applicant does not know the code number bit string and does not have the correct quantum credit card 1, another bell state orthogonal to the state of equation (1) is output, so the bank must detect fraud. Can do.

If it is determined by the above authentication that the quantum credit card 1 has been used by a legitimate user, as shown in FIG. Is converted (restored) to the second bell state shown in the above equation (9) by performing unitary transformation U ⁻¹ which is the inverse transformation, and locked. The unitary transformation U ⁻¹ is realized by, for example, a quantum circuit obtained by inverting the quantum circuit shown in FIG.

  Then, as shown in FIG. 18, the bank converts the quantum state of each bit into 0 qubits by using the password qubit string initialization device 8 as shown in the equation (38). Initialize (erase).

As shown in FIG. 19, the bank returns one quantum bit string (card quantum bit string K) of the pair of quantum bit strings converted to the second Bell state by the unitary transformation U ⁻¹ to the quantum credit card 1. The other qubit string (matching qubit string M) of the pair of qubit strings is stored and stored in the authentication qubit holder 6. As a result, the user and the bank again share the quantum bit string having the bell state (second bell state) represented by the above equation (9).

If it is determined that the user is a legitimate user, then the user performs, for example, an input of a withdrawal amount and an amount confirmation operation. For these techniques, a known ATM deposit / withdrawal technique is used.
And as shown in FIG. 20, while a user takes out the quantum credit card 1 from ATM3, he receives cash from a bank via ATM3, and complete | finishes a series of procedures.
As described above, the present authentication system can perform authentication without depositing at least the classic password to the bank (certification organization), and therefore can prevent illegal authentication in principle.

Hereinafter, the robustness of the present quantum authentication system will be described with reference to FIGS.
Considering a case where a malicious person forges the quantum credit card 1 and the password bit string and applies for authentication, the fraud detection probability P _E ^(N) can easily satisfy the condition shown in Expression (39). Recognize. It can be seen from this that fraud authentication can be detected with a very high probability by setting sufficiently large N.

Further, as shown in FIG. 21, when a malicious person obtains the quantum credit card 1 by stealing or the like and forges the password bit string and applies for authentication, The fraud detection probability _pe is obtained by calculation to be the expression (40).

Here, with respect to the equation (40), taking the parameters as in equation (41), fraud detection probability p _e per qubit is as equation (42).

  Thus, it can be seen that fraud per qubit can be detected with a probability of 0.13. Therefore, again, as shown in the equation (43), it can be understood that unauthorized authentication can be detected with a high probability by sufficiently increasing the bit number N of the code number bit string.

  When the authentication operation is not performed, the state of 2 qubits stored in the quantum credit card 1 and the authentication qubit holder 6 is defined by the above equation (1) or (3). In all cases, the maximum quantum entangled state. That is, as shown in FIG. 22 and Expressions (44) to (47), each reduced state in the quantum credit card 1 is a maximum entropy state represented by Expression (48) regardless of the bit value. is there.

Therefore, even if the quantum credit card 1 is stolen, the quantum credit card 1 does not include any useful information regarding the personal identification number bit string.
Similarly, each reduced state in the authentication quantum bit holder 6 on the bank side also depends on the bit value of the collation quantum bit string M as shown in FIG. 22 and equations (44) to (47). The maximum entropy state.

Therefore, since no information is included in the collation quantum bit string M stored by the bank, it can be seen that there is no personal information that is copied and leaked from the bank in the first place.
Next, the possibility of eavesdropping in the quantum communication channel 4 will be considered.
As shown in FIG. 23, when the condition of Expression (49) is satisfied, the password quantum bit string W transmitted through the quantum communication channel 4 is encoded in two non-orthogonal states.

Therefore, it is not completely duplicated by eavesdropping.
For example, even if an eavesdropper performs an optimal quantum measurement, the probability of an estimation determination error for the value of the personal identification number quantum bit string W at each bit is given by Expression (50).

  For example, when the parameter of Equation (51) is given, the probability of estimation judgment error per qubit is given by Equation (52), and the probability that the N-bit PIN qubit string W can be wiretapped correctly is It is given by equation (53).

  Therefore, the possibility of eavesdropping can be reduced exponentially by setting sufficiently large N bits in the personal identification number quantum bit string W. As described above, in principle, the eavesdropper cannot eavesdrop on the personal identification number quantum bit string W more accurately than the probability represented by the equation (53). This also applies to the bank side, and therefore the password number quantum bit string W cannot be read accurately even on the bank side.

In this way, since the personal identification number qubit string W is in the non-orthogonal quantum state, there is no concern that it will be duplicated accurately in any part of the authentication process.
Further, the code number qubit string W does not require entanglement control between large qubits, and a technique for controlling entanglement between two qubits is sufficient. Therefore, the required safety can be ensured by sufficiently increasing the number of bits N of the code number bit string without any particular technical difficulties.

  Further, as shown in FIG. 24, in the open / close lock device 5, there is no quantum entanglement between the combined system of the card qubit string K and the verification qubit string M and the personal identification number qubit string W. Therefore, even if the personal identification number quantum bit string W is initialized by the personal identification number quantum bit string initialization device 8, the same authentication operation can be performed by using the personal identification number bit string re-created by the user at the time of re-authentication. Can be realized repeatedly. As a result, since it is not necessary to always store the quantum code number bit string W in the quantum bit holder, there is no risk that the code number quantum bit string W together with the quantum credit card 1 will be stolen.

Thus, if this quantum authentication system is applied to the authentication at the bank, the user brings the quantum credit card 1 to the ATM 3, sets the quantum credit card 1, and inputs the password bit string according to the storage. Just because the bank performs authentication, the quantum authentication service can be received without feeling a significant change in the procedure.
[3] Others In the above-described embodiment, the case where the present quantum authentication system is applied to authentication in a financial institution such as a bank has been described. For example, authentication in a general store or a store, or on the Internet It can also be applied to commercial transactions.

  That is, the user only needs to bring the quantum credit card 1 to the store. If the user inserts the quantum credit card 1 into a quantum credit card reader (corresponding to the ATM3) provided in the store and inputs the password bit string, The card company will authenticate and complete the checkout process. With this alone, it is possible to receive a quantum authentication service with a high level of security that has never been achieved before.

Further, when applying to commercial transactions on the Internet, the user simply installs a personal identification number input device and a quantum credit card information transfer device (corresponding to the ATM3) at home, and performs the same authentication and settlement procedure as above. Since it can be performed, it is possible to receive a highly secure quantum authentication service on the Internet.
In the above-described embodiment, the bell state of the N qubit pairs initially prepared by the bank is set to the bell state “| +>” defined by the above equation (1). As in the bell state “|->” defined in the above, it is possible to obtain the same effect as in the above embodiment.

Furthermore, as another application example, the quantum authentication card 1 can be used as a quantum key card by using this authentication technique. In this case, an unlocking operation is performed for a legitimate user, and an unlocking operation is not performed for an unauthorized user.
Further, when the quantum authentication card 1 is of a rental type, the initialization (erase) operation of the personal identification number quantum bit string by the personal identification number quantum bit string initialization device 8 on the certification authority side can be omitted. That is, the certification authority rents the quantum authentication card 1 to the user and uses the quantum authentication card 1 only for one authentication. In this way, the password quantum bit string is not used repeatedly, so that it is not necessary to erase the information in the first place.

  Furthermore, by applying a known one-time password technique to the above quantum authentication system, an authentication operation similar to the above can be realized using a different password quantum bit string. Also in this case, for the same reason as described above, the initialization (erase) operation of the personal identification number qubit string on the certification authority side can be omitted.

  As described above in detail, according to the present invention, user authentication is performed without storing classical authentication information on the certification authority side, so that information leakage from the certification authority can be prevented, and the authentication technical field, For example, it is considered extremely useful for the quantum authentication technology field.

It is a quantum circuit diagram which shows an example of a unitary gate. It is a quantum circuit diagram which shows a CNOT gate. It is a quantum circuit diagram explaining operation | movement of a CNOT gate. It is a quantum circuit diagram explaining operation | movement of a CNOT gate. It is a quantum circuit diagram explaining operation | movement of a CNOT gate. It is a quantum circuit diagram explaining operation | movement of a CNOT gate. It is a block diagram which shows the structure of the quantum authentication system which concerns on one Embodiment of this invention. It is a schematic diagram for demonstrating the preparation step in this quantum authentication system. It is a schematic diagram for demonstrating the accommodation step and accommodation storage step in this quantum authentication system. It is a schematic diagram for demonstrating the conversion step in this quantum authentication system. It is a schematic diagram for demonstrating the conversion step in this quantum authentication system. It is a schematic diagram for demonstrating the production | generation step in this quantum authentication system. It is a schematic diagram for demonstrating the reproduction | regeneration step in this quantum authentication system. It is a schematic diagram for demonstrating the reproduction | regeneration step in this quantum authentication system. 2 is a quantum circuit diagram illustrating a unitary transformation U. FIG. It is a schematic diagram for demonstrating the measurement step in this quantum authentication system. It is a schematic diagram for demonstrating the reverse conversion step in this quantum authentication system. It is a schematic diagram for demonstrating the erasure | elimination step in this quantum authentication system. It is a schematic diagram for demonstrating the operation | movement after the authentication in this quantum authentication system. It is a schematic diagram for demonstrating the operation | movement after the authentication in this quantum authentication system. It is a schematic diagram for demonstrating the wiretapping possibility in this quantum authentication system. It is a schematic diagram for demonstrating the wiretapping possibility in this quantum authentication system. It is a schematic diagram for demonstrating the wiretapping possibility in this quantum authentication system. 5 is a schematic diagram for explaining the characteristics of a personal identification number qubit string W. FIG.

Explanation of symbols

1 Quantum authentication card (portable first quantum bit holder)
2 PIN code writing device (bell state qubit conversion device)
3 Automatic terminal (communication channel terminal)
4 Quantum communication channel 5 Opening / closing lock device (key unlocking device, authentication device and key locking device)
6 Authentication quantum bit holder (second quantum bit holder)
7 Bell measuring device (measuring device)
8 PIN code quantum bit string initialization device (initialization device)
9 storage unit 10 PIN number quantum bit string generation device (input PIN number quantum bit generation device)
DESCRIPTION OF SYMBOLS 11 Storage storage part 21 Conversion part 31 Transmission part 51 Key unlocking part 52 Authentication part 53 Key locking part 71 Measurement part 81 Initialization part

Claims (21)

A preparing step of preparing a pair of qubits composed of N qubits and in a bell state;
A storage step of storing one qubit string of the qubit pair in the first qubit holder;
A storage step of storing and storing the other qubit string of the qubit pair in a second qubit holder;
For the two qubit strings formed by the one qubit string stored in the first qubit holder and the other qubit string stored and stored in the second qubit holder, A conversion step of converting a portion corresponding to a portion where the value of the genuine N-bit PIN code bit string is 1 to another second bell state that is not orthogonal to the original first bell state;
A step of generating an input quantum code number bit string by replacing the input N bit code number bit string with a quantum bit string of a non-orthogonal quantum state in accordance with a value of the input N bit code number bit string;
The qubit string in the first qubit holder converted in the conversion step, the qubit string in the second qubit holder converted in the conversion step, and the input bit generated in the generation step A reproduction step of performing unitary transformation processing on the quantum code number bit string and reproducing a reproduction qubit pair in a bell state that is a pair of reproduction qubit strings composed of N reproduction qubits;
A measuring step for measuring whether or not the bell state of the regenerated qubit pair regenerated in the regenerating step matches the bell state of the qubit pair prepared in the preparing step;
If it is determined in the measurement step that they match, it is authenticated that the use by the first qubit holder is valid, and if it does not match, the use by the first qubit holder is confirmed. An authentication method using a quantum personal identification number, comprising: an authentication step for authenticating if invalid. An authentication unit, a portable first qubit holder for storing qubits, a second qubit holder for storing and storing qubits and supplying a qubit stored in the authentication unit, The authentication unit can be connected via a quantum communication channel, and the portable first qubit holder can be set to transmit a qubit stored in the portable first qubit holder to the authentication unit. In an authentication system comprising a communication channel terminal, an input password quantum qubit generation unit attached to the communication channel terminal, and a key unlocking unit, when performing authentication using a quantum password,
A preparing step of preparing a pair of qubits composed of N qubits and in a bell state;
A storage step of storing one qubit string of the qubit pair in the portable first qubit holder;
A storage step of storing and storing the other qubit string of the qubit pair in the second qubit holder;
For the two qubit strings formed by the one qubit string stored in the portable first qubit holder and the other qubit string stored and stored in the second qubit holder, 0 and 1 A conversion step of converting a portion corresponding to a portion where the value of the authentic N-bit code number bit string consisting of 1 to 1 into another second bell state that is non-orthogonal to the original first bell state;
In the input code number quantum bit generation unit, the input N-bit code number bit string is replaced with a non-orthogonal quantum state bit string according to the value of the input N-bit code number bit string. A generation step for generating
The portable first qubit holder that stores the qubit string converted in the conversion step is set in the communication path terminal, and the portable first quanta converted in the conversion step from the communication path terminal A transmission step of transmitting the qubit string in the qubit holder and the input quantum password bit string generated in the generation step to the authentication unit via the quantum communication path;
In the key unlocking unit, the qubit string in the portable first qubit holder converted in the conversion step, the qubit string in the second qubit holder converted in the conversion step, and A unitary transformation process is performed on the input quantum PIN bit string generated in the generation step, and a reproduced qubit pair in a bell state, which is a pair of reproduced qubits composed of N reproduced qubits, is obtained. A playback step to play,
In the authentication unit,
A measuring step for measuring whether or not the bell state of the regenerated qubit pair reproduced in the reproducing step matches the bell state of the qubit pair prepared in the preparing step;
If it is determined in the measurement step that they match, the portable first qubit holder authenticates the use by the portable first qubit holder, and if it does not match, the portable first qubit An authentication method using a quantum personal identification number, comprising: an authentication step for authenticating use by a holder as invalid. In the authentication method using the quantum personal identification number according to claim 1 or claim 2,
An inverse conversion step for performing an inverse conversion to return the bell state of the reproduced qubit pair reproduced in the reproduction step to the second bell state when it is authenticated in the authentication step that the use is valid. An authentication method using a quantum personal identification number, characterized by being configured as described above.   4. The authentication method using a quantum personal identification number according to claim 3, further comprising an erasing step of erasing the input quantum personal identification number bit string after the inverse conversion step. A first qubit holder for accommodating one qubit string of a pair of qubits consisting of N qubits prepared in advance and in a bell state;
A second qubit holder for storing and storing the other qubit string of the qubit pair;
For the two qubit strings formed by the one qubit string stored in the first qubit holder and the other qubit string stored and stored in the second qubit holder, A conversion unit that converts a portion corresponding to a portion where the value of the genuine N-bit PIN code bit string is 1 to another second bell state that is non-orthogonal to the original first bell state;
An input quantum code number bit string generating unit for generating an input quantum code number bit string by replacing the input N bit code number bit string with a quantum bit string in a non-orthogonal quantum state according to the value of the input N bit code number bit string; ,
A qubit sequence in the first qubit holder converted by the conversion unit, a qubit sequence in the second qubit holder converted by the conversion unit, and a quantum password bit string generation unit for input A key for performing unitary transformation processing on the generated input quantum PIN code bit string and reproducing a reproduced qubit pair in a bell state, which is a pair of reproduced qubits composed of N reproduced qubits Unlocking part,
A measurement unit for measuring whether or not the bell state of the reproduced qubit pair reproduced by the key unlocking unit matches the bell state of the previously prepared qubit pair;
If it is measured by the measuring unit that they match, it is authenticated that the use by the first quantum bit holder is valid, and if it does not match, the use by the first quantum bit holder is not used. An authentication system using a quantum personal identification number, characterized by comprising an authentication unit that authenticates if invalid. A portable first qubit holder for storing one qubit string of a pair of qubits consisting of N qubits prepared in advance and in a bell state;
A second qubit holder for storing and storing the other qubit string of the qubit pair;
For the two qubit strings formed by the one qubit string stored in the portable first qubit holder and the other qubit string stored and stored in the second qubit holder, 0 and 1 A conversion unit that converts a portion corresponding to a portion of a true N-bit PIN number bit string consisting of 1 to a second bell state that is non-orthogonal to the original first bell state;
An input quantum code number bit string generating unit for generating an input quantum code number bit string by replacing the input N bit code number bit string with a quantum bit string in a non-orthogonal quantum state according to the value of the input N bit code number bit string; ,
By setting the portable first quantum bit holder that stores the quantum bit string converted by the converting unit, the quantum bit string in the portable first quantum bit holder and the input quantum PIN code bit string generating unit A communication channel terminal that transmits the input quantum PIN code bit string generated in step 1 through a quantum communication channel;
The quantum bit string in the portable first quantum bit holder connected to the communication channel terminal via the quantum communication channel and converted by the conversion unit, and the second quantum converted by the conversion unit A unitary transformation process is performed on the quantum bit string in the bit holder and the input quantum PIN code bit string generated by the input quantum PIN bit string generation unit, so that a reproduced quantum comprising N reproduced qubits is obtained. A key unlocking unit for reproducing a reproduced qubit pair in a bell state which is a pair of bit strings;
A measuring unit for measuring whether the bell state of the regenerated qubit pair reproduced by the key unlocking unit matches the bell state of the previously prepared qubit pair;
If it is measured by the measurement unit to be coincident, it is authenticated that the use by the portable first qubit holder is valid, and if it is not coincident, the portable first qubit is measured. An authentication system using a quantum personal identification number, comprising: an authentication unit that authenticates use by a holder. In the authentication system using the quantum personal identification number according to claim 5 or 6,
When the authenticating unit authenticates the use, the inverse conversion is performed to return the bell state of the reproduced qubit pair in the bell state reproduced by the key unlocking unit to the second bell state. An authentication system using a quantum personal identification number, characterized by comprising a key-locking unit for performing the operation.   8. The authentication system using a quantum personal identification number according to claim 7, further comprising an initialization unit that erases the input quantum personal identification number bit string. The first quantum bit holder used in the authentication system using the quantum personal identification number according to claim 5 or 6,
A pair of qubits consisting of N qubits, which stores one qubit of a pair of qubits in a bell state, and having a storage unit that stores a qubit sequence converted by the conversion unit. Quantum bit holder characterized by The second quantum bit holder used in the authentication system using the quantum code number according to claim 5 or 6,
A qubit holder having a storage unit for storing and storing the other qubit string of the qubit pair.   A bell-state qubit conversion device comprising the conversion unit used in the authentication system using the quantum password according to claim 5 or 6.   7. An input quantum code number bit string generation device for input comprising the input quantum code number bit string generation unit used in the authentication system using the quantum code number according to claim 5 or 6. The communication channel terminal used in the authentication system using the quantum personal identification number according to claim 6,
By setting the first quantum bit holder that stores the quantum bit string converted by the conversion unit, the quantum bit string in the first quantum bit holder and the input quantum PIN code bit string generated by the input unit are generated. A communication path terminal comprising: a transmission unit that transmits the input quantum PIN code bit string via the quantum communication path.   A key unlocking device comprising the key unlocking unit used in the authentication system using the quantum personal identification number according to claim 5 or 6.   An authentication apparatus comprising the measurement unit and the authentication unit used in the authentication system using the quantum personal identification number according to claim 5 or 6.   A key-locking device having the key-locking unit used in the authentication system using the quantum personal identification number according to claim 7.   An initialization apparatus comprising the initialization unit used in the authentication system using the quantum personal identification number according to claim 8. One qubit string of a pair of qubits consisting of N qubits in the first bell state is stored in the first qubit holder, and the other qubit string is stored in the second qubit string. Storing in the bit holder;
The binary bit string consisting of a combination of 0 and 1 is applied to the one quantum bit string in the first quantum bit holder to obtain the bell state of the qubit corresponding to the part where the value of the binary bit string is 1 A second bell state that is non-orthogonal to the bell state of
Acquiring a quantum bit string subjected to the action of the binary bit string from the first quantum bit holder, and generating a quantum bit string of a non-orthogonal quantum state according to the bit value by receiving the binary bit string When,
A unitary transformation process is performed on the qubit string subjected to the action of the acquired binary bit string, the generated qubit string in the non-orthogonal quantum state, and the other qubit string in the second qubit holder. Replaying a pair of regenerated qubits consisting of N regenerated qubits and in a third bell state,
Measuring whether the third bell state coincides with the first bell state;
Authenticating use by the first qubit holder when measured to match, and
A quantum authentication method comprising:   19. The quantum authentication method according to claim 18, wherein the binary bit string is a bit string corresponding to a password determined by a user of the first quantum bit holder.   The quantum authentication method according to claim 18, wherein the binary bit string is a bit string corresponding to biometric information of a user of the first quantum bit holder. A binary bit string consisting of a combination of 0 and 1 is applied to one of the pair of qubits consisting of N qubits and one of the qubit pairs in the first bell state. An acquisition means for acquiring, from the first quantum bit holder, a qubit string in which the bell state of the qubit corresponding to the portion having a value of 1 is a second bell state that is non-orthogonal to the original bell state;
A second qubit holder storing the other qubit string of the qubit pair in the first bell state;
Generating means for receiving a binary bit string and generating a non-orthogonal quantum state quantum bit string corresponding to the bit value;
A unitary transformation process is performed on the qubit sequence acquired by the acquisition unit, the qubit sequence in the non-orthogonal quantum state generated by the generation unit, and the other qubit sequence in the second qubit holder. Reproducing means for reproducing a reproduction qubit pair consisting of N reproduction qubits, which is a pair of reproduction qubits in the third bell state,
Measuring means for measuring whether the third bell state coincides with the first bell state;
Authenticating means for authenticating use by the first qubit holder when measured by the measuring means is valid;
A quantum authentication device characterized by comprising: