AU2020100261A4 - The quantum secret information direct communication method with mutual authentication - Google Patents

Abstract

A b s t r a c t The invention discloses a quantum secret information direct communication method with mutual authentication. It relates to the field of quantum communication technology. This method can transmit secret message directly from one user to another in one step without the assistance of a third party. This method simplifies the transmission of secret information. If the sender Alice does not know IDB ( the identity of receiver Bob ), she cannot pass the eavesdropping detection. If the receiver Bob does not know IDA ( the identity of sender Alice ), he cannot pass the eavesdropping detection either. Then the receiver cannot recover the secret information. That is, the identity of both parties can be authenticated during communication, and the transmission of secret information is more secure. This method does not require the receiver to be equipped with quantum memory and quantum unitary operator. In the method, the sender only needs to be able to prepare single photon and Bell state, and the receiver only needs to be able to measure single photons and Bell state. This reduces the deployment cost and facilitates the application of quantum communication networks. Communication parties exchange identity. The sender sends the quantum sequence to the receiver, which consists of decoy photon and secret message photon. Upon receiving the quantum sequence, the receiver divided the quantum sequence into decoy photon sequence and secret message photon sequence. The receiver measures the decoy photons and gets the measurement results. The sender announces the initial state of decoy photons. s the measurement results of decoy No-0 terminate the protocol hotons equal to its 1mitial state? Yes The receiver measures the secret message photons and gets the measurement results. Then he can get the secret message based on the measurement results. Figure 1

Description

The quantum secret information direct communication method with mutual authentication

Technical Field?

The invention discloses a quantum secret information direct communication method with mutual authentication. It relates to the field of quantum communication technology.

Technical Background

The security of secret information transmission is the most basic problem that quantum communication technology needs to solve.

At present, users have the following disadvantages when transmitting secret information.

1) To ensure secret information's safety transfer, users need to generate a pre-share key. Then sender uses the key to encrypt the secret information and sends the encrypted information to receiver. The method is very complicated.

2) To ensure secret information's safety transfer, users need the assistance of a trusted third party. Therefore, the complexity of the scheme is increased, and the risk of eavesdropping on secret information is increased.

3) In order to realize the transmission of secret information, it usually needs two steps and the process is tedious in quantum communication.

4) The existing secret information transmission methods do not consider the issue of identity authentication, and there are hidden security risks.

5) In order to realize the secure transmission of information, both communication parties need to equip expensive quantum devices, such as quantum memory and quantum unitary operator, which is not conducive to the promotion and application of quantum communication networks.

Summary of the invention

The invention provides a quantum secret information direct communication method with mutual authentication, which can alleviate the above problems.

The technical scheme adopted by the invention is as follows.

The invention provides a quantum secret information direct communication method with mutual authentication, including the following steps:

SI > The sender Alice and the receiver Bob exchange their identities ID_A and ID_B. ID_A, ID_b and the secret message are Mbit machine code, N is natural number;

S2> Alice prepares an ordered 2N qubit pairs which are in one of the states {|01),|10), Qubits compose an ordered sequences S. Alice sends S'to Bob. The quantum sequences S is prepared by the following steps:

al > prepared the quantum sequence Sa which is used to send secret message. Sa is an ordered N qubit pairs, and it prepared based on the value of secret message.

a2> prepared the quantum sequence Sb which are used to check eavesdropping. Sb is an ordered N qubit pairs, and it prepared based on the value of ID_A.

a3 > Alice inserts decoy photons of Sb into qubit sequence of secret message Sa based on the values of ID_B. Sa and Sb compose an ordered sequences S.

S3 > Upon receiving the photons, Bob gets the positon of decoy photons according to ID_B.

S4> Bobmeasures decoy photons in the corresponding basis. If the value of the ith bit of ID a is 0, Bob measures them in Ζ={|θ), 1)} basis. If the value of the ith bit of ID a is 1, he measures them in Bell basis. Finally, he stores the measurement results and publicly announces an acknowledgment.

S5 > Alice announces the initial states of the decoy photon pairs.

S6> Bob’s measurement result should be same as Alice’s prepared state. If the error rate is higher than the predetermined error rate, they will terminate the protocol and restarts from Stepl. After all the decoy photon pairs announced by Alice are checked, the protocol will

2020100261 24 Feb 2020 continue to the next step.

S7> Using the same way as described in Step 3 to Step 4, Alice and Bob can also authenticate each other. The initial state of the decoy photon pairs is the same as IDa. And only authenticated Bob can get the secret message.

S8> Bob discards measurement results of the decoy pairs. For the remaining photon pairs, he measures them in the basis Ζ={|θ),|1)}or Bell basis randomly. Then he can get the secret message based on the remaining measurement results.

The technical effect of the technical scheme is as follows:

To ensure secret information's safety transfer, users need the assistance of a trusted third 10 party. Therefore, the complexity of the scheme is increased, and the risk of eavesdropping on secret information is increased.

During the secret information transmission, it does not need the assistance of the third party, and only needs one step transmission to realize the safe transmission of secret information from the sender to the receiver, which simplifies the process of information 15 transmission. During the eavesdropping detection, if the sender does not know the identity of the receiver IDb, she cannot pass the eavesdropping detection, if the receiver does not know the identity of the sender ID_A, he cannot pass the eavesdropping detection. That is, the protocol has a mutual authentication function. This method does not require quantum memory and quantum unitary operator. The sender only needs to be able to prepare single photon and 20 Bell state, and the receiver only needs to be able to measure single photons and Bell state.

This reduces the deployment cost and facilitates the application of quantum communication networks.

Further, in step SI, the identities are exchanged by BB84 protocol ( quantum key distribution protocol). By changing each time, i.e. each communication will modify the 25 identity of both parties to ensure the security of communications.

In step al, if the ith bit (l<i<N) of secret message is 0, Alice produces the state) 01) or |10). Otherwise, she produces the state|<//) or|^ .

In step a2, if the value of the ith bit of IDa is 0, Alice produces the state 101) or |10).

Otherwise, she produces the state |^⁺) or φ ).

In step a3, if the value of the ith bit of IDb is 0, Alice inserts the decoy photons in front of the secret message. Otherwise, Alice inserts the decoy photons behind the secret message.

The four Bell states is denoted as |^⁺) , 1^) , \ψ⁺) and \ψ~) , where

In order to make the above purpose, features, and advantages of the invention more obvious and easier to understand, the following is a detailed description with the accompanying drawings.

Description of drawings

Figure 1 The process of the secret information encoding and decoding phase

Figure 2 The relationship between the detection probability d and the secret information I obtained by Eve.

Detailed Description

Here is an example to illustrate the implementation process of this scheme.

Suppose Alice is the sender, Bob is the receiver, Alice wants to send the secret message

M=1100 to Bob. The identity of Alice is ID_A= 0110, Bob is IDb= 1010.

SI, The sender Alice and the receiver Bob exchange their identities ID_A and IDb by BB84 protocol ( quantum key distribution protocol). ID_A, IDb and the secret message are A-bit machine code, N is natural number;

S2, Alice prepares an ordered 8 qubit pairs which are in one of the states {|θί) ,|10), | φ⁺) = (| O) 10) +11) 11)), | φ ) = -^= (| 0) 10) -11) 11)) }, all of these qubits compose an ordered sequences S. Alice sends S to Bob. The quantum sequences S is prepared by the following steps:

al > prepared the quantum sequence Sa which is used to send secret message. If the ith bit (1 <i<N) of secret message is 0, Alice produces the state101)or|10). Otherwise, she produces the state\φ'\orl^^-). In this example M=1100, so we can assume that 5'₍=| )

a2> prepared the quantum sequence Sb which are used to check eavesdropping. If the value of the ith bit of /D_t is 0, Alice produces the state 101) or 110^. Otherwise, she produces the state |^⁺) or|</> ). In this example IDa= 0110, so we can assume that Sb={|01) |io)_b a3 > Alice inserts decoy photons of Sb into qubit sequence of secret message Sa based on the values of ID_B. If the value of the ith bit of IDb is 0, Alice inserts the decoy photons in front of the secret message. Otherwise, Alice inserts the decoy photons behind the secret message. Sa and Sb compose an ordered sequences S. In this example ID_B= 1010, Sa={, |^-),|1θ) ,|10)}, S_s={|01) ,|fy),|^),|10) }, according to the rules, we can get S={|fy^,|01), Ι^),μ-),|ιο),μ-},|ιο>,|ιο)

S3 > Upon receiving the photons, Bob gets the positon of decoy photons according to ID_B.

S4> Bob measures decoy photons in the corresponding basis. If the value of the ith bit of ID a is 0, Bob measures them in Ζ={|θ), 1)} basis. If the value of the ith bit of ID· is 1, he measures them in Bell basis. Finally, he stores the measurement results and publicly announces an acknowledgment. In this example ID_A= 0110, we can get the measurement bases are Zbasis> Bell basis. Bell basis and Zbasis.

S5> Alice announces the initial states of the decoy photon pairs, Sb={ 101), |φ^, |φ

S6> Bob’s measurement result should be same as Alice’s prepared state. If the error rate is higher than the predetermined error rate, they will terminate the protocol and restarts from Stepl. After all the decoy photon pairs announced by Alice are checked, the protocol will continue to the next step.

2020100261 24 Feb 2020

S7> Using the same way as described in Step 3 to Step 4, Alice and Bob can also authenticate each other. The initial state of the decoy photon pairs is the same as /D_t. And only authenticated Bob can get the secret message.

S8> Bob discards measurement results of the decoy pairs. For the remaining photon pairs, he measures them in the basis Z= {| 0), 11)} or Bell basis randomly. Then he can get the secret message based on the remaining measurement results.

The relationship among these information is shown in Table 1, where Ζ={|θ),|1)}, The

144)’i^⁺>^andi^’>’ ^where 1^=^44)+101¹)^ four Bell states is denoted as

Table 1. Relationship among the initial state, measurement basis, measurement result and the secret message initial state measure basis measurement results secret message

Z basis01 |°i> o

Bell basis \ψ⁺) or \ψ )

Z basis10 |io> o

Bell basis \ψ⁺) or \ψ )

Z basis 00 or 11

/) ________________________- 1

Bell basis\φ

Z basis 00 or 11

H

Bell basis|a)

Therefore, the proposed protocol achieves the secure transmission of data from Alice to Bob.

The process of the information encoding and decoding phase is shown in Figure 2. The white dots represent 101) or 110), and black dots represent | φ⁺) or).

Alice

Bob

M

1100

IDb

1010

IDb

1010

measurement encoding phase ιυ_Λ

0110

IDa

0110

M

1100 decoding phase

Figure 2 The process of the information encoding and decoding phase

The quantum secret information direct communication method can against some common attacks.

A. The impersonation attack

Eve may try to impersonate one of two legal users to communicate with the other one. Suppose Eve generates a sequence Se. and sends the forged message to Bob in Step 2. After Bob measures the decoy photons in Se, Eve must announces the initial states of decoy photons to Bob. However, Eve cannot public the correct initial states without knowing the ID a, and the comparison will be failed. On the other hand, suppose Eve impersonate Bob to obtain the encoding message of Alice. To recover the secret message, Eve has to obtain the right position of decoy photons. However, she has no idea about the identity ID a and IDb.

According to the analysis above, the present protocol is secure against the impersonation attack.

B. The intercept-and-resend attack

In the communication phase, in order to recover the secret message without being detected, Eve can launch an intercept-and-resend attack as follows. In Step 2, Eve intercepts the sequence 5 and measure it with the in Z basis or Bell basis. Then Eve generate the same states based on the measurement result and sends them to Bob. Without knowing the positon of decoy photons, Eve will be detected inevitably.

In detail, let us first consider the case that the state of decoy photon pair is φ⁺). If Eve intercepts this qubit and performs a measurement on it along the Bell basis, the measurement result will beSubsequently, Eve retransmits this result state <// ^ to Bob. As a result, no error has been introduced. If Eve choose the Z basis, the measurement result is| 00) or|l 1). Then Eve sends|00)or|ll) to Bob. Bob measures it in Bell basis and obtains |^⁺) or p/ each with probability of 1/2. Thus, the error rate introduced by Eve is 50%. Therefore, the 3 1 11 probability for Eve to pass the security checking is— = — xl + — x —.

Now considering the case that the state of decoy photon is|01), If Eve intercepts this qubit and performs a measurement on it along the Z basis, the measurement result will be 101). Subsequently, Eve retransmits this result state |01) to Bob. As a result, no error has been introduced. If Eve choose the Bell basis, the measurement result is |^⁺^or|^/. Then Eve sends|^⁺^or / to Bob. Bob measures it in Z basis and obtains |01)or|10) each with probability of 1/2. Thus, the error rate introduced by Eve is 50%. Therefore, the probability 3 1 11 for Eve to pass the security checking '^s^ ⁼ y^x'⁺T^xT·

Thus, for Eve’s intercept-measure-resend attack, the probability of being detected is 3 d = 1 - (—). This probability is approximate to 1, if n is large enough.

C. Man-in-the-middle attack

In Step 2, if Eve intercepts the sequence S from Alice and Bob. She prepares another sequence Se and sends it to Bob. However, Alice only announces the initial states of the decoy photon pairs during the protocol. Eve knows nothing about the identity 1D₍ and ID#, so Eve cannot correctly distinguish between the decoy photons and secret message photons. Therefore, even if Eve catches these qubits, she cannot obtain the secret message, and her attack cannot pass the eavesdropping check.

D. Entangle-Measure Attack

In this section we discuss the entangle-measure attack. Eve intercepts sequence S and adds an ancillary state | ε_a / to every particle. Then she performs the unitary attack operation

E on the composed system. All the transmitted particles are sent together before eavesdropping is detected in the proposed protocol. Because Eve does not know which particle is used to detect eavesdropping, she can only perform the same attack operation on all the particles. As for Eve, the state of qubits are distinguishable from the complete mixture, so all qubits are considered in either of the states 10) or 11) with an equal probability p₀ = p_x =0.5.

After attack by Eve, the state 10) and 11) become |<X j = E = «|θ,ό’_οο) + Λ | ) |A)⁼£|M = c|O,£_lo) + i7|l,_£11)

Where |a|² + = 1, |c|² +|ri|² =1, |_fl|² =|ri|² =F,|fy =|c|² =D.

Suppose Alice prepares Bell states | and sends to Bob, after attack operator E is performed, the state of the composed system becomes ^_ A θ’%θ) +£|k %1 ))fi£ + Ify O,£,o) + ¢/ |1, £, , ))_s£] (β | θ’ θ’ %0 ) + b | 0,1, <£qi ) + C 11, 0, £,0 ) + d 11’ 1’ <- 1 ABE =^[(φ’%^ο)+<Φ’<%)).4_£ |°h + (*|°’£·⁰¹)l¹)^]

After measurement, \φ)_Ε„ will collapse to (a| O,f_oo) + c|l, |0)_s or (£>|0, f₀₁) + d |1, ε_χ j„ |l)_seach with probability of 1/2.

Obviously, when Bob performs Bell measurement on the decoy photons, the probability for Eve cannot to be detected is /Ή=^(Ν² + \d\²)=\a\² = \d\²=F

So the lower bound of the detection probability d is d = 1 - ρ\φ) = 1-F=D

Eve can eavesdrop the maximal amount of the information I is

I = -F log₂ F + (1 - F) log₂ (1 - F) , I = -(1 - d) log₂ (1 - d) + d log₂ d .

When Eve gains the information, the detection probability is shown in Fig. 3.

Figure 3 detection probability of eavesdropping information

The above results show that if Eve wants to gain the full information (/=1), the probabilities of the eavesdropping detection is d = 50%.

E. Correctness of the secret message

To ensure that Bob receives the same secret message M' as M, he needs to compare the message with Alice. They can employ the one-way hash function (i.e., A(): {0,1} {0,1}”, where n denotes the length of the inputted data, and m denotes the length of the hash code) on their secret message M' and M to obtain two hash codes, h(M') and h(M), each of m bit length. Finally, Alice publishes all or part of h(M'). If Bob finds that Alice has published the same value as herself, it means the secret message have been sent successfully.

The innovation of the method is mainly reflected in the following aspects:

1) During the secret information transmission, it does not need the assistance of the third party, and only needs one step transmission to realize the safe transmission of secret information from the sender to the receiver

2) This method adds the function of identity authentication, and realizes the identity authentication of participants when transmitting secret information.

3) This method does not require quantum memory and quantum unitary operator. The sender only needs to be able to prepare single photon and Bell state, and the receiver

2020100261 24 Feb 2020 only needs to be able to measure single photons and Bell state. This reduces the deployment cost and facilitates the application of quantum communication networks.

Claims (4)

1. Claims

   1. A quantum secret information direct communication method with mutual authentication, it includes the following steps:

   Sl> The sender Alice and the receiver Bob exchange their identities IDa and IDb. IDa, IDb and the secret message are TV-bit machine code, N is natural number;

   S2> Alice prepares an ordered 2N qubit pairs which are in one of the states {|01),|10), |^⁺),}}, ^aH °f these qubits compose an ordered sequences S. Alice sends 5'to Bob. The quantum sequences S is prepared by the following steps:

   al > prepared the quantum sequence Sa which is used to send secret message. Sa is an ordered N qubit pairs, and it prepared based on the value of secret message.

   a2> prepared the quantum sequence Sb which are used to check eavesdropping. Sb is an ordered N qubit pairs, and it prepared based on the value of ID_A.

   a3 > Alice inserts decoy photons of Sb into qubit sequence of secret message Sa based on the values of ID_B. Sa and Sb compose an ordered sequences S.

   S3 > Upon receiving the photons, Bob gets the positon of decoy photons according to ID_B.

   S4> Bob measures decoy photons in the corresponding basis. If the value of the ith bit of IDa is 0, Bob measures them in Z={|0), 1)} basis. If the value of the ith bit of IDa is 1, he measures them in Bell basis. Finally, he stores the measurement results and publicly announces an acknowledgment.

   S5 > Alice announces the initial states of the decoy photon pairs.

   S6> Bob’s measurement result should be same as Alice’s prepared state. If the error rate is higher than the predetermined error rate, they will terminate the protocol and restarts from Stepl. After all the decoy photon pairs announced by Alice are checked, the protocol will continue to the next step.

   S7> Using the same way as described in Step 3 to Step 4, Alice and Bob can also authenticate each other. The initial state of the decoy photon pairs is the same as IDa. And only authenticated Bob can get the secret message.

   S8> Bob discards measurement results of the decoy pairs. For the remaining photon pairs, he measures them in the basis Z= {| 0), 11)} or Bell basis randomly. Then he can get the secret message based on the remaining measurement results.
2. 2. According to claim 1, the quantum secret information direct communication method with mutual authentication, it is characterized in that the identities IDa and IDb are exchanged by BB84 protocol (quantum key distribution protocol).
3. 3. According to claim 1, the quantum secret information direct communication method with mutual authentication, its characteristics include

   In step al, if the ith bit (l<z< N) of secret message is 0, Alice produces the state) 01) or 110). Otherwise, she produces the state|<//)or|^fy .

   In step a2, if the value of the ith bit of IDa is 0, Alice produces the state 101) or |10). Otherwise, she produces the state <//) or </> )

   In step a3, if the value of the ith bit of ID_B is 0, Alice inserts the decoy photons in front of the secret message. Otherwise, Alice inserts the decoy photons behind the secret message.
4. 4. According to claim 1, the quantum secret information direct communication method with mutual authentication, its characteristics include

   The four Bell states is denoted as |^⁺) , , \ψ⁺) and \ψ~) , where