CN105391548A - Node trust-based quantum trust assessment method - Google Patents

Abstract

The invention discloses a node trust-based quantum trust assessment method, including modeling of a quantum trust model and a method for quantum trust assessment. Compared with the prior art, the method uses a trust node-based credible quantum relay network as a research object, introduces trust management into a quantum communication network, uses assessment of a trust value of a node as a basis to build a safe and credible quantum communication network, and uses the trust value as a basis for judging whether users in the quantum communication network are credible; by means of unique characteristics of a quantum entanglement effect and quantum teleportation, the node trust-based quantum trust assessment method is researched and proposed, and the idea and the process of quantum trust assessment are explained in detail; and finally feasibility, reasonability and safety of the node trust-based quantum trust assessment method proposed by the invention are analyzed, thereby providing a valuable new idea and new method for building a safe and credible quantum communication network.

Description

Based on the quantum method for evaluating trust that node is trusted

Technical field

The present invention relates to a kind of quantum method for evaluating trust, particularly relate to the quantum method for evaluating trust of trusting based on node.

Background technology

Quantum communications refer to a kind of novel communication modes utilizing quantum coherent superposition, entangled quantum effect and quantum teleportation to carry out information transmission, and existing quantum communications security protocol and technology etc. are all impliedly relevant to trust, or presupposed certain and trusted prerequisite, or object is to create or obtain certain trusting relationship.Therefore, be similar to classic network, in quantum communication network, two kinds of trusting relationships that are mutually related mainly are discussed to the research of trusting: (1) objective trust (trust to object node) is evidential trust, thus can accurately describe, reasoning and checking; (2) subjective trust (trust of master nodes, master nodes refers to the individuality or colony that are made up of the mixture of people or people and object node), as the cognitive phenomenon of one, it is a kind of subjective conviction, be other subjective judgement of a specific order of special characteristic to master nodes or behavior, and this subjective judgement is independent of the monitoring to body feature and behavior.Subjective trust is important prerequisite and the basis of objective trust, and it is in essence based on conviction, has very large uncertainty (showing as randomness, diversity and ambiguity), cannot accurately describing and validating in addition.And the main difficulty that subjective trust carries out formal research is also how to carry out modeling to this uncertainty.

Summary of the invention

Object of the present invention is just the quantum method for evaluating trust proposing to solve the problem to trust based on node.

The present invention is achieved through the following technical solutions above-mentioned purpose:

The present invention includes the modeling of quantum trust model and the method for quantum trust evaluation,

The modeling of quantum trust model:

In quantum communications, a quantum state can be expressed as | ψ >=α | and 0>+ β | 1>, wherein α ²+ β ²=1; Also consider in quantum communication network simultaneously, trust and there is the uncertain factors such as randomness, diversity and ambiguity, therefore describe each node belongs in the degree of membership of certain factor by means of the degree of membership of intuitionistic Fuzzy Sets and non-affiliated topology degree;

Definition 1: set U as nonempty set, u _ifor the element in U, an intuitionistic Fuzzy Sets on U is defined as:

A＝{＜u _i,μ _A(u _i),υ _A(u _i)＞|u _i∈U}

Definition 2: assuming that i-th node u in quantum communication network _i, evaluate a jth factor quantum state of its trust value represent; But due in actual applications, the significance level of each trust factor is different, increases a weight t to each trust factor at this _j; Like this, the trust value evaluating i-th user can be expressed as:

$|{\mathrm{\α}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\Σ}}{t}_j\left({\mathrm{cos\θ}}_j\right|0>+{\mathrm{sin\θ}}_j|1>)---\left(1\right)$

According to the cos in definition 1 and formula (1) ²θ _ju _ito the degree of membership of a jth trust factor, sin ²θ _ju _ito the non-affiliated degree of a jth factor, cos ²θ _j+ sin ²θ _j=1; t _j(j=1,2 ..., m) be the weight coefficient of each trust factor, meet

Evaluating each node u in quantum communication network _ieach factor of the trust value degree of membership of fuzzy intuition collection theory and non-affiliated degree describe, and complete the modeling of each node subjective trust, this model is referred to as quantum trust model;

The method of quantum trust evaluation:

Step 1: initial phase

Assuming that prior u _iby the mode of registration, its information about trust is stored in TTP there, is expressed as with quantum state:

$\begin{array}{c}|{\mathrm{\α}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\Σ}}{t}_j\left({\mathrm{cos\θ}}_j|0>+{\mathrm{sin\θ}}_j|1>\right)\\ ={\mathrm{cos\γ}}_i|0>+{\mathrm{sin\γ}}_i|1>\end{array}---\left(2\right)$

In formula (2), the weight coefficient t of each trust factor _jmeet θ _ja corresponding jth trust factor; γ _ithe description that corresponding i-th node is comprehensively trusted, cos ²γ _iu _ito the degree of membership of j trust factor, sin ²γ _iu _ito the non-affiliated degree of j trust factor, cos ²γ _i+ sin ²γ _i=1, wherein i=1,2 ..., n;

Assuming that TTP and each user u _ibetween share the quantum bit that is in for a pair in Entangled State wherein particle T returns TTP to own, and particle A returns u _iall, in order to illustrate conveniently, setting u ₃think and u ₁communication;

Step 2:u ₃hope and u is sent to TTP by classical channel ₁the request of communication;

Step 3:TTP receives and asks and be confirmed to be u ₃after, and inform u ₁, u ₃want to communicate with him;

Step 4: the transmission realizing trust value by means of quantum teleportation;

TTP is by u ₁be kept at the trust value information of its there in advance, be prepared into u by TTP ₁the quantum state of trust value throughput subchannel sends to u ₃, detailed process is as follows:

1. TTP is to quantum state carry out Bell base combined measurement with particle T, obtain measurement result;

Specific practice is: the quantum state that TTP is prepared into the quantum state be in Entangled State shared with them particle T and particle A carry out computing, obtains three particle systems residing quantum state is:

In formula (3) for tensor product, | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tAbe four Bell state, be respectively:

$|{\mathrm{\φ}}^{+}{>}_{TA}=\left(\right|00>+|11>)/\sqrt{2}$

$|{\mathrm{\φ}}^{-}{>}_{TA}=\left(\right|00>-|11>)/\sqrt{2}$

$|{\mathrm{\ψ}}^{+}{>}_{TA}=\left(\right|01>+|10>)/\sqrt{2}$

$|{\mathrm{\ψ}}^{-}{>}_{TA}=\left(\right|01>-|10>)/\sqrt{2}$

2. TTP sends to u measurement result ₃;

3. u ₃according to the classical information received, the particle A that only need have him does corresponding operation, recovers u ₁the original quantum state of trust value

Setting node in advance and TTP arrange: classical information 00,01,10 and 11 represents the measurement result of TTP respectively | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tA.Work as u ₃when receiving information 00,01,10 and 11 of TTP transmission, just do corresponding unitary operations, can u be obtained ₁the quantum state of trust value

Step 5:u ₃according to what recover calculate u ₁trust value, and pass judgment on whether trust u according to the trust value that calculates ₁.

Beneficial effect of the present invention is:

The present invention is the quantum method for evaluating trust of trusting based on node, compared with prior art, the present invention with the credible Quantum repeater network based on trusted node for research object, trust management is incorporated in quantum communication network, safe and reliable quantum communication network is built based on the trust value of evaluation node, and using trust value as the whether believable foundation of each user in judge quantum communication network; By means of the monopolizing characteristic such as entangled quantum effect and quantum teleportation, study and propose the quantum method for evaluating trust of trusting based on node, the thinking of quantum trust evaluation and process have been described in detail; The feasibility of the quantum method for evaluating trust of trusting based on node that ultimate analysis the present invention proposes, reasonability and fail safe, this provides a kind of valuable new approaches and new method for setting up safe and reliable quantum communication network.

Accompanying drawing explanation

Fig. 1 is the quantum communication network structure chart with trusted third party TTP;

Fig. 2 is the quantum trust evaluation flow chart with trusted third party TTP.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described:

Thinking based on the quantum method for evaluating trust that node is trusted:

Find by analyzing, based in the credible junction network of trusted node, the trust evaluation between each node can be evaluated by means of trusted third party TTP (trustedthirdparty).If there be n node (user) u in quantum communication network ₁, u ₂..., u _nwith a trusted third party TTP, first each node will carry out registering (such as submitting the attributes such as history credit worthiness, identity information to) at TTP when joining quantum communication network; During registration, portray the uncertainty of each nodal community by means of the degree of membership of intuitionistic Fuzzy Sets and non-affiliated topology degree, complete the quantitative description (i.e. the mathematical modeling of subjective trust) of subjective trust; Between each node before securely communicating, obtain the information of certain node about trusting by means of Quantum Entangled States, quantum teleportation etc.; Then according to the trust value information obtaining node, calculate the trust value of certain node, more whether evaluate the other side according to the trust value calculated credible.

Concrete thought (as shown in Figure 1) based on the quantum trust evaluation that node is trusted: assuming that node u ₃think and node u ₁communication, but u ₃and do not know u ₁whether credible, in order to prevent u ₁deception u ₃, u ₃related Evaluation u is obtained from TTP there ₁the relevant information of trusting, u ₃by means of the information that TTP provides, calculate u ₁trust value, and pass judgment on u according to trust value ₁whether credible.Note: consider the clear of network structure in Fig. 1, in figure, TTP has only marked u ₁, u ₃, u ₃;

As shown in Figure 2, the present invention includes the modeling of quantum trust model and the method for quantum trust evaluation,

The modeling of quantum trust model:

In quantum communications, a quantum state can be expressed as | ψ >=α | and 0>+ β | 1>, wherein α ²+ β ²=1; Also consider in quantum communication network simultaneously, trust and there is the uncertain factors such as randomness, diversity and ambiguity, therefore describe each node belongs in the degree of membership of certain factor by means of the degree of membership of intuitionistic Fuzzy Sets and non-affiliated topology degree;

Definition 1: set U as nonempty set, u _i(i=1,2 ..., be n) element in U, an intuitionistic Fuzzy Sets on U is defined as:

A＝{＜u _i,μ _A(u _i),υ _A(u _i)＞|u _i∈U}

Wherein, μ _a: U → [0,1], υ _a: U → [0,1],

For 0≤μ _a(u _i)+υ _a(u _i)≤1.

μ _a(u _i) represent u _ito the degree of membership of set A, υ _a(u _i) represent u _ito the non-affiliated degree of set A.

Definition 2: as shown in Figure 1, assuming that i-th node u in quantum communication network _i(i=1,2 ..., n), evaluate its trust value jth (j=1,2 ..., m) individual factor quantum state represent; But due in actual applications, the significance level of each trust factor is different, increases a weight t to each trust factor at this _j(j=1,2 ..., m); Like this, the trust value evaluating i-th user can be expressed as:

$|{\mathrm{\α}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\Σ}}{t}_j\left({\mathrm{cos\θ}}_j\right|0>+{\mathrm{sin\θ}}_j|1>)---\left(1\right)$

According to the cos in definition 1 and formula (1) ²θ _ju _ito the degree of membership of a jth trust factor, sin ²θ _ju _ito the non-affiliated degree of a jth factor, cos ²θ _j+ sin ²θ _j=1; t _j(j=1,2 ..., m) be the weight coefficient of each trust factor, meet

Evaluating each node u in quantum communication network _i(i=1,2, ..., n) each factor of trust value describes with the degree of membership of fuzzy intuition collection theory and non-affiliated degree, reflect the actual conditions (uncertainty of subjective trust) of subjective trust more objectively, complete the modeling of each node subjective trust, this model is referred to as quantum trust model by the present invention.

The method of quantum trust evaluation:

Step 1: initial phase

Assuming that prior u _i(i=1,2 ..., n) by the mode of registration, its information about trust is stored in TTP there, is expressed as with quantum state (being prepared by TTP before sending):

$\begin{array}{c}|{\mathrm{\α}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\Σ}}{t}_j\left({\mathrm{cos\θ}}_j|0>+{\mathrm{sin\θ}}_j|1>\right)\\ ={\mathrm{cos\γ}}_i|0>+{\mathrm{sin\γ}}_i|1>\end{array}---\left(2\right)$

In (2) formula, the weight coefficient t of each trust factor _jmeet θ _ja corresponding jth trust factor; γ _ithe description that corresponding i-th node is comprehensively trusted, cos ²γ _iu _ito the degree of membership of j trust factor, sin ²γ _iu _ito the non-affiliated degree of j trust factor, cos ²γ _i+ sin ²γ _i=1, wherein i=1,2 ..., n.

Assuming that TTP and each user u _i(i=1,2 ..., share the quantum bit be in for a pair in Entangled State n) wherein particle T (the 1st quantum bit) returns TTP to own, and particle A (the 2nd quantum bit) returns u _i(i=1,2 ..., n) all.In order to illustrate conveniently, we suppose u ₃think and u ₁communication (representing with adding thick lines in Fig. 1).

Step 2:u ₃hope and u is sent to TTP by classical channel ₁the request of communication.

Step 3:TTP receives and asks and be confirmed to be u ₃after, and inform u ₁, u ₃want to communicate with him.

Step 4: the transmission realizing trust value by means of quantum teleportation.

TTP is by u ₁be kept at the trust value information of its there in advance, be prepared into u by TTP ₁the quantum state of trust value (namely wanting the quantum state of Teleportation), throughput subchannel sends to u ₃, detailed process is as follows:

1. TTP is to quantum state carry out Bell base combined measurement with particle T, obtain measurement result (classical information).

Specific practice is: the quantum state that TTP is prepared into the quantum state be in Entangled State shared with them particle T and particle A carry out computing, obtains three particle systems residing quantum state is:

In formula (3) for tensor product, | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tAbe four Bell state, be respectively:

$|{\mathrm{\φ}}^{+}{>}_{TA}=\left(\right|00>+|11>)/\sqrt{2}$

$|{\mathrm{\φ}}^{-}{>}_{TA}=\left(\right|00>-|11>)/\sqrt{2}$

$|{\mathrm{\ψ}}^{+}{>}_{TA}=\left(\right|01>+|10>)/\sqrt{2}$

$|{\mathrm{\ψ}}^{-}{>}_{TA}=\left(\right|01>-|10>)/\sqrt{2}$

2. TTP sends to u measurement result (classical information) ₃.

3. u ₃according to the classical information received, the particle A that only need have him does corresponding operation (as shown in table 1), recovers u ₁the original quantum state of trust value

Assuming that node is prior and TTP arranges: classical information 00,01,10 and 11 represents the measurement result of TTP respectively | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tA.Work as u ₃when receiving classical information 00,01,10 and 11 of TTP transmission, just do corresponding unitary operations, can u be obtained ₁the quantum state of trust value

Table 1 and classical information 00,01,10 and 11 corresponding unitary operations

Such as: as shown in Table 1, if TTP is prior and u ₃appoint, receive 01 and just do $Z=\left[\begin{array}{cc}1& 0\\ 0& -1\end{array}\right]$ Conversion, recovers u ₁original quantum state its its be specifically transformed to:

$\begin{array}{c}Z\⊗\left({\mathrm{cos\γ}}_1|0>-{\mathrm{sin\γ}}_1|1>\right)=\left[\begin{array}{cc}1& 0\\ 0& -0\end{array}\right]\⊗\left(\left[\begin{array}{c}{\mathrm{cos\γ}}_1\\ 0\end{array}\right]-\left[\begin{array}{c}0\\ {\mathrm{sin\γ}}_1\end{array}\right]\right)\\ =\left[\begin{array}{cc}1& 0\\ 0& -1\end{array}\right]\⊗\left[\begin{array}{c}{\mathrm{cos\γ}}_1\\ -{\mathrm{sin\γ}}_1\end{array}\right]\\ =\left[\begin{array}{c}{\mathrm{cos\γ}}_1\\ {\mathrm{sin\γ}}_1\end{array}\right]={\mathrm{cos\γ}}_1|0>+{\mathrm{sin\γ}}_1|1>\\ =|{\mathrm{\α}}_1{>}_{u_1}\end{array}$

Step 5:u ₃according to what recover calculate u ₁trust value, and pass judgment on whether trust u according to the trust value that calculates ₁.

Feasibility analysis:

Dividing to send by quantum teleportation and quantum entanglement and realize remote quantum communications, particularly transmit unknown quantum state, is remote quantum communications and the requisite link of distributed quantum network.At present, quantum teleportation and quantum entanglement distribution obtain realization at the optical fiber of moderate distance.The quantum method for evaluating trust that the present invention proposes has used the characteristic such as quantum teleportation, quantum entanglement, is feasible in the application of the quantum communication network in future.Specifically, following two aspects are shown:

(1) in quantum teleportation, when representing u ₁trust information is converted into TTP will send u to ₃original quantum state time, be prepare u by TTP ₁the quantum state of trust value throughput subchannel sends to u ₃; TTP uses this quantum state and each user u subsequently _i(i=1,2 ..., n) shared, the quantum bit be in Entangled State carry out computing, will transform into a Bell state a part (or | 0> state and | one of 1> state).This illustrates works as when quantum state is transferred on particle A, just u is described ₃receive the unknown quantum state that TTP throughput subchannel sends over so Teleportation and quantum non-clone principle not contradiction, also illustrate that the present invention realizes trust value transmission by means of quantum teleportation is feasible with calculating, be also be rational in following practical application simultaneously.

(2) in quantum entanglement, the both sides no matter sharing Entangled State are how far apart, as long as a side (TTP in the present invention) measures two particles in oneself hand, then and the opposing party (u in the present invention ₃) particle in hand will collapse accordingly.In the present invention, u ₃according to the measurement result that TTP sends at classical channel, to the unknown quantum state that TTP throughput subchannel sends over do corresponding operation (as shown in table 1), will obtain with TTP according to u ₁the original quantum state prepared of trust information therefore, the present invention realizes trust value transmission by means of quantum entanglement is feasible with calculating, and is also be rational in following practical application.

Safety analysis:

Analyze the fail safe of the quantum trust evaluation that the present invention proposes, mainly from the Preventing spoofing (side that communicates (such as u of the present invention ₁) cheat the opposing party (the such as u of the present invention communicated ₁)) and prevent the aspects such as eavesdropping from analyzing.

(1) Preventing spoofing

In Preventing spoofing, due to u ₃think and u ₁communication, u ₃hope and u is sent to TTP by classical channel ₁the request of communication, TTP receives and asks and inform u ₁after wanting to communicate with him, the u that oneself is prepared ₁the quantum state of trust value throughput subchannel sends u to ₃, measurement result (classical information) is sent to u by classical channel simultaneously ₃, u ₃recovered by the measurement result received and calculate u ₁trust value.Because TTP is u ₁and u ₃the third party trusted, TTP tells u before communicating ₁, u ₃want to communicate with him; u ₃be according to TTP by quantum teleportation pass over about u ₁trust information, and calculate u ₁trust value be true and reliable, therefore u ₁and u ₃there is not fraudulent problem in both sides.

(2) anti-eavesdrop

Before analysis, first suppose in communication process, have listener-in Eve (Eve can be the listener-in of internal system (as Fig. 1), also can be the listener-in of its exterior), he wants that obtaining TTP by eavesdropping sends to user u ₃original quantum state

If 1. Eve is peripheral listener-in

In the present invention, TTP and u ₃share the quantum bit be in for a pair in Entangled State tTP has particle T (the 1st quantum bit), u ₃have particle A (the 2nd quantum bit), and any quantum bit information in assailant Eve is not in Entangled State quantum bit.If Eve has intercepted TTP and has issued user u by classical channel ₃information (that is to say, Eve obtains the measurement result of TTP), but the quantum bit information in Quantum Entangled States is not had due to Eve, even if so he obtains classical information, he can not pass through certain operations (and Eve does not know which type of operation this carries out yet) and recover original quantum state obviously, Eve can not obtain any available information about unknown quantum state in this case, and the trust model that therefore the present invention proposes can prevent the eavesdropping of peripheral listener-in Eve.

If 2. Eve is internal system listener-in

In the present invention, although TTP, u ₃the quantum bit be in for a pair in Entangled State is shared with Eve | φ ⁺> _tAif Eve has intercepted and has sent to u ₃classical information, but Eve do not know this carry out which type of operation, he also can not recover original quantum state therefore, the trust model that the present invention proposes can prevent the eavesdropping of internal system listener-in Eve.

In addition, in the method for evaluating trust of the present invention's research, u ₁the quantum state of trust value information according to u by TTP ₁some attributes (such as the identity etc. of history credit worthiness, user) prepare, then throughput subchannel sends to u ₃, there is certain authority.According to quantum uncertainty principle in quantum mechanics and quantum non-clone principle (quantum signal transmitted in quantum channel is all indeterminable to any recipient), if assailant's (wrapping other users in this quantum network system and graphical user) wishes to go to determine by measuring then cause just be not present in after measured.From this angle, in theory u ₃obtain (provided by TTP, represent u ₁the quantum state of trust value information ) can be perfectly safe.

More than show and describe general principle of the present invention and principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and specification just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.Application claims protection range is defined by appending claims and equivalent thereof.

Claims (1)

1., based on the quantum method for evaluating trust that node is trusted, it is characterized in that: comprise the modeling of quantum trust model and the method for quantum trust evaluation,

The modeling of quantum trust model:

In quantum communications, a quantum state can be expressed as | ψ >=α | and 0>+ β | 1>, wherein α ²+ β ²=1; Also consider in quantum communication network simultaneously, trust and there is the uncertain factors such as randomness, diversity and ambiguity, therefore describe each node belongs in the degree of membership of certain factor by means of the degree of membership of intuitionistic Fuzzy Sets and non-affiliated topology degree;

Definition 1: set U as nonempty set, u _ifor the element in U, an intuitionistic Fuzzy Sets on U is defined as:

A＝{<u _i,μ _A(u _i),υ _A(u _i)>|u _i∈U}

Definition 2: assuming that i-th node u in quantum communication network _i, evaluate a jth factor quantum state of its trust value represent; But due in actual applications, the significance level of each trust factor is different, increases a weight t to each trust factor at this _j; Like this, the trust value evaluating i-th user can be expressed as:

$|{\mathrm{\&alpha;}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\&Sigma;}}{t}_j\left({\mathrm{cos\&theta;}}_j\right|0>+{\mathrm{sin\&theta;}}_j|1>)---\left(1\right)$

According to the cos in definition 1 and formula (1) ²θ _ju _ito the degree of membership of a jth trust factor, sin ²θ _ju _ito the non-affiliated degree of a jth factor, cos ²θ _j+ sin ²θ _j=1; t _j(j=1,2 ..., m) be the weight coefficient of each trust factor, meet

Evaluating each node u in quantum communication network _ieach factor of the trust value degree of membership of fuzzy intuition collection theory and non-affiliated degree describe, and complete the modeling of each node subjective trust, this model is referred to as quantum trust model;

The method of quantum trust evaluation:

Step 1: initial phase

Assuming that prior u _iby the mode of registration, its information about trust is stored in TTP there, is expressed as with quantum state:

$\begin{array}{c}|{\mathrm{\&alpha;}}_i{>}_{u_i}=\underset{j=1}{\overset{m}{\&Sigma;}}{t}_j\left({\mathrm{cos\&theta;}}_j|0>+{\mathrm{sin\&theta;}}_j|1>\right)\\ ={\mathrm{cos\&gamma;}}_i|0>+{\mathrm{sin\&gamma;}}_i|1>\end{array}---\left(2\right)$

In formula (2), the weight coefficient t of each trust factor _jmeet θ _ja corresponding jth trust factor; γ _ithe description that corresponding i-th node is comprehensively trusted, cos ²γ _iu _ito the degree of membership of j trust factor, sin ²γ _iu _ito the non-affiliated degree of j trust factor, cos ²γ _i+ sin ²γ _i=1, wherein i=1,2 ..., n;

Assuming that TTP and each user u _ibetween share the quantum bit that is in for a pair in Entangled State wherein particle T returns TTP to own, and particle A returns u _iall, in order to illustrate conveniently, setting u ₃think and u ₁communication;

Step 2:u ₃hope and u is sent to TTP by classical channel ₁the request of communication;

Step 3:TTP receives and asks and be confirmed to be u ₃after, and inform u ₁, u ₃want to communicate with him;

Step 4: the transmission realizing trust value by means of quantum teleportation;

TTP is by u ₁be kept at the trust value information of its there in advance, be prepared into u by TTP ₁the quantum state of trust value throughput subchannel sends to u ₃, detailed process is as follows:

1. TTP is to quantum state carry out Bell base combined measurement with particle T, obtain measurement result;

Specific practice is: the quantum state that TTP is prepared into the quantum state be in Entangled State shared with them particle T and particle A carry out computing, obtains three particle systems residing quantum state is:

In formula (3) for tensor product, | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tAbe four Bell state, be respectively:

$|{\mathrm{\&phi;}}^{+}{>}_{TA}=\left(\right|00>+|11>)/\sqrt{2}$

$|{\mathrm{\&phi;}}^{-}{>}_{TA}=\left(\right|00>-|11>)/\sqrt{2}$

$|{\mathrm{\&psi;}}^{+}{>}_{TA}=\left(\right|01>+|10>)/\sqrt{2}$

$|{\mathrm{\&psi;}}^{-}{>}_{TA}=\left(\right|01>-|10>)/\sqrt{2}$

2. TTP sends to u measurement result ₃;

3. u ₃according to the classical information received, the particle A that only need have him does corresponding operation, recovers u ₁the original quantum state of trust value

Setting node in advance and TTP arrange: classical information 00,01,10 and 11 represents the measurement result of TTP respectively | φ ⁺> _tA, | φ ^-> _tA, | ψ ⁺> _tAwith | ψ ^-> _tA.Work as u ₃when receiving information 00,01,10 and 11 of TTP transmission, just do corresponding unitary operations, can u be obtained ₁the quantum state of trust value

Step 5:u ₃according to what recover calculate u ₁trust value, and pass judgment on whether trust u according to the trust value that calculates ₁.