Background
Yao A C [1] first introduced Secure multiparty computing (SMPC) in the million Fuzz problem, a fundamental and important topic in classical cryptography. In Yao a C's millionaire problem, two millionaires wish to know who is more abundant without revealing the true amount of property to each other. Then, Boudot F et al [2] construct an equivalence comparison method to determine whether two millionaire states are equally affluent. SMPCs can be used in many applications such as covert bidding and auctions, anonymous voting, e-commerce, data mining, etc.
As a special kind of SMPC, the Classical Privacy Comparison (CPC) aims at deciding whether the secrets of different parties are equal without revealing their true values. With the development of Quantum technology, CPC has been generalized to the Quantum domain to produce Quantum Privacy Comparison (QPC), the security of which is based on Quantum mechanics principles rather than computational complexity. Lo H K [3], however, indicates that in both cases, the equality function cannot be safely measured. This situation requires additional assumptions, such as a Third Party (TP).
The first QPC method was designed by Yang Y G et al [4] with the aid of Einstein-Podolsky-Rosen (EPR) pairs and a TP. The security of this method is based on a one-way hash function. Specifically, after the secrets of two users are encrypted by a one-way hash function, they are encoded into an EPR pair by a local unitary operation. In the same year, QPC methods based on single photon were designed by Yang YG et al [5 ]. In this method, after the secrets of two users are encrypted by a one-way hash function, they are encoded into single photons by a unitary operation. In 2010, a QPC method based on the Greenberger-Horne-Zeilinger (GHZ) state was devised by Chen X B et al [6], where the secrets of two users are encrypted by a one-time pad key generated by single particle measurement of the particles in the original GHZ state. In this method, TP needs to perform unitary operation. In 2012, a novel ERP pair-based QPC method was constructed by Tseng H Y et al [7], where the one-time-pad key used to encrypt the secrets of two users resulted from single-particle measurements on the particles of the original EPR pair. Fortunately, this approach requires neither unitary nor one-way hash functions. In 2012, a QPC method based on Bell-state entanglement swapping was proposed by Liu W et al [8], where the one-time pad key used to encrypt the secrets of two users was obtained by Bell-based measurements on the Bell states generated after the original Bell-state entanglement swapping. Moreover, this method does not require unitary operation. However, Liu W J et al [9] indicate that in the method of document [8], TP can extract the secrets of two users without being detected by launching a Bell-based measurement attack, and propose an improved method to remedy this vulnerability. So far, in addition to the above mentioned methods, many other two-party QPC methods [10-34] have also been devised by using different quantum states and quantum techniques.
Regarding the role of TP, Chen X B et al [6] first introduced the semi-loyalty model. That is, the TP loyalty performs the entire process, recording all intermediate computing data but may attempt to derive the users' secrets from the recording with the constraint that they cannot be eroded by adversaries, including non-loyal users. However, Yang Y G et al [12] indicated that this semi-loyalty TP model is not reasonable, and it is believed that a reasonable model should be as follows: TPs cannot be corroded by adversaries, including non-loyal users, but are allowed to misbehave according to their own thoughts. In fact, to date, this assumption of TP is the most reasonable.
Assuming that there are K parties, each has a secret. They want to know if their K secrets are equal and not compromised. If the two-party QPC method is used to solve this multi-party equality comparison problem, the same two-party QPC method has to be performed (n-1) n (n-1)/2 times so that the efficiency is not high enough. In 2013, Chang Y J et al [35] propose a first Multi-party Quantum privacy Comparison (MQPC) method using an n-particle GHZ type, and once executed, can implement equivalence Comparison of secrets of any two parties among K users. Subsequently, an MQPC method [36] based on d-dimensional ground states and quantum Fourier transforms, and an MQPC method [37] based on n-order entangled states and quantum Fourier transforms were designed. However, until now, only a few MQPC methods exist.
Based on the analysis, the invention provides a multi-party quantum privacy comparison method based on Bell-state entanglement swapping, which realizes the equality comparison of K different user secrets by utilizing Bell-state entanglement swapping. The method can realize the equality comparison of the secrets of any two parties in K users only once. The third party can know the result of the comparison of the secrets of each two users but cannot know their true value. Each user cannot know the true value of the secrets of the other K-1 users.
Reference to the literature
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Disclosure of Invention
The invention aims to design a multi-party quantum privacy comparison method based on Bell-state entanglement swapping, which realizes the equality comparison of K different user secrets by utilizing Bell-state entanglement swapping.
A multiparty quantum privacy comparison method based on Bell state entanglement swapping comprises the following two processes:
s1) preparation phase: (1) and documents [4-5 ]]Similar to the QPC method, K users, P
1、P
2、...、P
KA secret one-way hash function H is shared in advance. X
iHas a hash value of
P
iWill be her
Is divided into
Group of
Where each group contains two binary bits. If N mod 2 ═ 1, one 0 should be P
iIs added to
(2)P
iPreparation of
All are at
Quantum state of (2), TP preparation
All are at
The quantum state of (a). Then, P
iSelecting the first particle from each quantum state to form an ordered sequence
The remaining second particle of each quantum state automatically forms another ordered sequence
TP selects the first particle from each quantum state to form an ordered sequence
The remaining second particle of each quantum state automatically forms another ordered sequence
(3) For security detection, P
1Preparing one more time of the two phases of
+>The sequence of L' quantum states of (a) is described
TP again prepares a mixture of all at phi
+>The sequence of L' quantum states of (A) is denoted as D
T′. Then P
1Respectively to be provided with
Each of the first and second particles of the Bell state in (b) is inserted in
And
in the same position, respectively, P
1To obtain
And
TP separately converts D
T′Each of the first and second particles of the Bell state in (b) is inserted in
And
at the same position of (A), correspondingly, TP is obtained
And
then the,P
1And TP exchange among them
And
to ensure P
1-the transmission security of the TP quantum channel,
the entanglement correlation between two different particles in each Bell state is used to detect the presence of an eavesdropper. To ensure TP-P
1Transmission security of quantum channels, D
T′The entanglement correlation between two different particles in each Bell state is used to detect the presence of an eavesdropper. If no eavesdropper is present, P
1And TP discards the sample particles and performs the next step. (4) For the
P
1To pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>Then
If it is not
Is phi
->Then, then
If it is not
Is | Ψ
+>Then, then
If it is not
Is | Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. In TP hands this
The collapsed Bell state was noted
S2) K-1 th round of comparison, K2, 3, 4. (1) P
kAnd TP are prepared by all being at phi
+>Is arranged in a sequence of L' quantum states to ensure
And
security of the phase exchange. If no eavesdropper is present, P
kAnd TP discards the sample particles and performs the next step. (2) For the
P
kTo pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Then
If it is not
Is phi->Then, then
If it is not
Is | Ψ
+>Then, then
If it is not
Is | Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. TP also pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>Then, then
If it is not
Is phi
->Then, then
If it is not
Is | Ψ
+>Then, then
If it is not
Is | Ψ
->Then, then
(3) For the
k users collaborate together to compute
And will be
And sent to the TP. Here, m is 1, 2. P
i(i-1, 2., m-1, m + 1.,. k-2, k-1) and P
mRespectively to be provided with
And
the result of (2) is sent to P
kFor calculating
Then, TP calculation
And
TP will
Is sent to P
mAnd P
k. If it is not
P
mAnd P
kTo obtain X
m=X
k(ii) a Otherwise, they know X
m≠X
k。
The invention provides a multi-party quantum privacy comparison method based on Bell-state entanglement swapping, which realizes the equivalence comparison of K different user secrets by utilizing Bell-state entanglement swapping. The method can realize the equality comparison of the secrets of any two parties in K users only once. The third party can know the result of the comparison of the secrets of each two users but cannot know their true value. Each user cannot know the true value of the secrets of the other K-1 users.
Detailed Description
The technical solution of the present invention is further described with reference to the following examples.
1. Coding rules
Suppose there are K users, P
1、P
2、...、P
KIn which P is
iHaving a secret integer X
i,i=1,2,...,K。X
iIn that
Binary representation of a field as
Here, the first and second liquid crystal display panels are,
j-0, 1. They want to know that every two different xs are assisted by a semi-loyal TP
iWhether or not equal. They agreed with TP the following rules: phi
+>、|Ф
->、|Ψ
+>And | Ψ
->Representing two classical bits 00, 01, 10 and 11, respectively.
2. Multi-party quantum privacy comparison method
The method comprises the following two processes:
s1) preparation phase: (1) and documents [4-5 ]]Similar to the QPC method, K users, P
1、P
2、...、P
KA secret one-way hash function H is shared in advance. X
iHas a hash value of
P
iWill be her
Is divided into
Group of
Where each group contains two binary bits. If N mod 2 ═ 1, one 0 should be P
iIs added to
(2)P
iPreparation of
All are at
Quantum state of (2), TP preparation
All are at
The quantum state of (a). Then, P
iSelecting the first particle from each quantum state to form an ordered sequence
The remaining second particle of each quantum state automatically forms another ordered sequence
TP selects the first particle from each quantum state to form an ordered sequence
The remaining second particle of each quantum state automatically forms another ordered sequence
(3) For security detection, P
1Preparing one more time of the two phases of
+>The sequence of L' quantum states of (a) is described
TP again prepares a mixture of all at phi
+>L' ofSequence of quantum states, denoted D
T′. Then P
1Respectively to be provided with
Each of the first and second particles of the Bell state in (b) is inserted in
And
in the same position, respectively, P
1To obtain
And
TP separately converts D
T′Each of the first and second particles of the Bell state in (b) is inserted in
And
at the same position of (A), correspondingly, TP is obtained
And
then, P
1And TP exchange among them
And
to ensure P
1-the transmission security of the TP quantum channel,
between two different particles in each Bell stateEntanglement correlation is used to detect the presence of an eavesdropper. To ensure TP-P
1Transmission security of quantum channels, D
T′The entanglement correlation between two different particles in each Bell state is used to detect the presence of an eavesdropper. If no eavesdropper is present, P
1And TP discards the sample particles and performs the next step. (4) For the
P
1To pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>Then, then
If it is not
Is phi
->Then, then
If it is not
Is | Ψ
+>Then, then
If it is not
Is | Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. In TP hands this
The collapsed Bell state was noted
S2) K-1 th round of comparison, K2, 3, 4. (1) P
kAnd TP are prepared by all being at phi
+>Is arranged in a sequence of L' quantum states to ensure
And
security of the phase exchange. If no eavesdropper is present, P
kAnd TP discards the sample particles and performs the next step. (2) For the
P
kTo pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Then
If it is not
Then
If it is not
Is | Ψ
+>Then, then
If it is not
Is | Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. TP also pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>Then, then
If it is not
Is phi
->Then, then
If it is not
Then
If it is not
Is | Ψ
->Then, then
(3) For the
k users collaborate together to compute
And will be
And sent to the TP. Here, m is 1, 2. P
i(i-1, 2., m-1, m + 1.,. k-2, k-1) and P
mRespectively to be provided with
And
the result of (2) is sent to P
kFor calculating
Then, TP calculation
And
TP will
Is sent to P
mAnd P
k. If it is not
P
mAnd P
kTo obtain X
m=X
k(ii) a Otherwise, they know X
m≠X
k。
3. Analysis and discussion
1) Accuracy of measurement
With respect to X
mAnd X
kAn equality comparison of (m 1, 2.,. K-1 and K2, 3, 4.,. K), K users requiring a calculation
Moreover, TP needs to be calculated
And
according to the entanglement exchange process of the MQPC method, the invention can obtain
Thus, in the MQPC method of the present invention, XmAnd XkThe result of the equality comparison of (c) is correct.
2) Safety feature
As the one-way hash function is adopted to encrypt the secret, the method can be easily found out that the MQPC method disclosed by the invention is immune to the problems of external attack, participant attack and information leakage.
3) Comparison with previous QPC method
A comparison of the MQPC method of the present invention with Yang et al method [4], Chen et al method [6], Liu et al method [8] and Chang et al method [35] is described in Table 1.
It must further be noted that in the current MQPC method [35-37] and the MQPC method of the present invention, different quantum methods are used to achieve the equality comparison. Specifically, Chang et al [35] utilized the entanglement correlation between two different particles of one n-particle GHZ class; both Liu et al [36] and Wang et al [37] use quantum Fourier transforms. However, the method of the present invention uses quantum entanglement swapping.
TABLE 1 comparison of the MQPC method of the present invention with the previous QPC method
Example (b):
1. example of application of Quantum privacy comparison method
Here, K is 3 as an example. Alice, Bob, and Charlie have three secret integers X, Y and Z, respectively, where
And
here, x
j,y
j,z
jE {0, 1 }. With the help of a semi-loyal TP, they want to know if X, Y and Z are equal for each two. Alice, Bob, Charlie, and TP agree on the following rules: phi
+>、|Ф
->、|Ψ
+>And | Ψ
->Representing two classical bits 00, 01, 10 and 11, respectively. They achieve an equality comparison of every two secret integers by performing the following steps.
S1) preparation phase: (1) and documents [4-5 ]]Similar to the QPC method of (1), Alice, Bob and Charlie share a secret one-way hash function H in advance. X, Y and Z have hash values of
And
Alice/Bob/Charlie will have her/his/her X
#/Y
#/Z
#Is divided into
Group of
Where each group contains two binary bits. If N mod 2 ═ 1, a 0 should be added by Alice/Bob/Charlie to
Alice/Bob/Charlie/TP preparation
Is in a quantum state
Then, Alice/Bob/Charlie/TP picks out the first particle from each quantum state to form an ordered sequence
The remaining second particles of each quantum state automatically form another ordered sequence
(3) For security detection, Alice/TP prepares a second pass all at φ
+>The sequence of L' quantum states of (A) is denoted as D
A′/D
T′. Then Alice/TP respectively converts D
A′/D
T′Each of the first and second particles of the Bell state in (b) is inserted in
And
at the same position. Accordingly, Alice/TP gets
And
alice and TP then exchange between themselves
And
in order to ensure the transmission security of the Alice-TP/TP-Alice quantum channel, D
A′/D
T′The entanglement correlation between two different particles in each Bell state is used to detect the presence of an eavesdropper. If no eavesdropper is present, Alice and TP discard the sample particles and proceed to the next step. (4) For the
Alice pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>/|Ф
->/|Ψ
+>/|Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. TP in hand this
The collapsed Bell state was noted
S2) first round comparison: (1) Bob/TP preparation was prepared by all at phi
+>Is arranged in a sequence of L' quantum states to ensure
And
security of the phase exchange. If no eavesdropper is present, Bob and TP discard the sample particles and proceed to the next step. (2) For the
Bob pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>/|Ф
->/|Ψ
+>/|Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. TP also pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>/|Ф
->/|Ψ
+>/|Ψ
->Then, then
In TP hands this
The collapsed Bell state is noted
(3) For the
Alice and Bob collaborate together to compute
And will be
And sent to the TP. Alice will send
The result of (2) is sent to Bob for calculation
Then, TP calculation
And
then, TP converts R
ABTo Alice and Bob. If R is
AB0, Alice and Bob yield X-Y; otherwise, they know that X ≠ Y.
S3) second round comparison: (1) Charlie/TP preparation is prepared by all being at phi
+>Is arranged in a sequence of L' quantum states to ensure
And
security of the phase exchange. If no eavesdropper is present, Charlie and TP discard the sample particles and proceed to the next step. (2) For the
Charlie pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>/|Ф
->/|Ψ
+>/|Ψ
->Then, then
Thus, in TP hands
The corresponding pair of particles is collapsed into one of four Bell states. TP also pair
Each pair of particles in (a) is subjected to a Bell-based measurement to obtain a corresponding measurement result
If it is not
Is phi
+>/|Ф
->/|Ψ
+>/|Ψ
->Then, then
(3) For the
Alice, Bob, and Charlie collaboratively compute together
And will be
And sent to the TP. Alice and Bob will respectively
And
the result of (2) is sent to Charlie for calculation
Then, TP calculation
And
at the same time, for
Alice, Bob, and Charlie collaboratively compute together
And will be
And sent to the TP. Alice and Bob will respectively
Results of (1) and
sent to Charlie for computation
Then, TP calculation
And
finally, TP will R
BCSent to Bob and Charlie. If R is
BCBob and Charlie yield Y ═ Z; otherwise, they know that Y ≠ Z. On the other hand, TP will R
ACAnd sending the information to Alice and Charlie. If R is
ACAlice and Charlie yield X ═ Z; otherwise, they know that X ≠ Z.
For clarity, the Bell-state entanglement swapping process between the four participants of the three-way QPC method described above is depicted in FIG. 1.
2. Analysis and discussion
The three-way QPC method described above is still discussed here as an example.
1) Accuracy of measurement
For the three-way QPC approach described above, there are a total of three cases where correctness needs to be discussed.
(1) Equality comparison of Alice and Bob secrets
For an equality comparison of X and Y, Alice and Bob need to compute
Moreover, TP needs to be calculated
And
from fig. 1, the following evolution can be derived:
therefore, in the three-way QPC method described above, the results of the equivalence comparison of X and Y are correct.
(2) Equality comparison of secrets for Bob and Charlie
For the equality comparison of Y and Z, Alice, Bob, and Charlie require computation
Moreover, TP needs to be calculated
And
from fig. 1, the following evolution can be derived:
therefore, in the three-way QPC method described above, the result of the equality comparison of Y and Z is correct.
(3) Equality comparison of Alice and Charlie secrets
For equal comparisons of X and Z, Alice, Bob, and Charlie require computation
Moreover, TP needs to be calculated
And
from fig. 1, the following evolution can be derived:
therefore, in the three-way QPC method described above, the results of the equivalence comparison of X and Z are correct.
3. Summary of the invention
The invention provides a multi-party quantum privacy comparison method based on Bell-state entanglement swapping, which realizes the equivalence comparison of K different user secrets by utilizing Bell-state entanglement swapping. The method can realize the equality comparison of the secrets of any two parties in K users only once. The third party can know the result of the comparison of the secrets of each two users but cannot know their true value. Each user cannot know the true value of the secrets of the other K-1 users.