Abstract:
The invention discloses a platform authentication method suitable for trusted network connect (TNC) architecture based on tri-element peer authentication (TePA). The method relates to a platform authentication protocol of tri-element peer authentication, and the protocol improves network security as compared with prior platform authentication protocols; in the platform authentication protocol of the TNC architecture based on TePA, a policy manager plays a role as a trusted third party, which is convenient for concentrated management, thus enhancing manageability; the invention relates to the platform authentication protocol of the TNC architecture based on TePA, has different implementation methods and is beneficial for different dispositions and realizations.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Phase application of PCT/CN2009/075942, filed Dec. 24, 2009, and published in the Chinese language as WO/2010/124504 A1 on Nov. 4, 2010. This application claims priority to Chinese patent application No. 200910022232.6, entitled “PLATFORM AUTHENTICATION METHOD SUITABLE FOR TRUSTED NETWORK CONNECT ARCHITECTURE BASED ON TRI-ELEMENT PEER AUTHENTICATION” and filed with the State Intellectual Property Office on Apr. 28, 2009, which is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to the field of network security technologies, and in particular to a platform authentication method suitable for a trusted network connect architecture based on tri-element peer authentication. 
     BACKGROUND OF THE INVENTION 
     With the development of informatization, problems of malicious software such as viruses and worms are growing. Currently, more than 35,000 forms of malicious software have been found, and more than 40,000,000 computers are infected each year. To prevent these attacks, it is required not only secured transmission and inspection of data while they are being inputted, but also protection starting from the source, i.e., every endpoint connected to the network. However, conventional security protection techniques can no longer protect against the various malicious attacks. 
     To this end, the Trusted Computing Group (TCG) have developed a network access specification based on Trusted Computing (TC), i.e., Trusted Network Connect (TNC), hereinafter referred to as TCG-TNC, which includes an open architecture for endpoint integrity and a set of standards that ensure secure interoperability. The set of standards can protect a network as needed by the user, to a user-defined level. Basically, the TCG-TNC is to establish a connection starting from endpoint integrity. Firstly, a set of policies for the operation of the systems within a trusted network are established. Only those endpoints that comply with the network-specified policies are allowed to access the network, and those devices that do not comply with the policies will be isolated and located by the network. Due to the use of a Trusted Platform Module (TPM), attacks from rootkits can also be blocked. A rootkit is an attack script, a modified system program, or a set of attack scripts or tools, for illegally obtaining the highest privileges in a targeted system. The architecture of TCG-TNC is shown in  FIG. 1 . 
     In  FIG. 1 , the Vendor-Specific IMC-IMV Messages Interface (IF-M) is an interface between an Integrity Measurement Collector (IMC) and an Integrity Measurement Verifier (IMV); the TNC Client-TNC Server Interface (IF-TNCCS) is an interface between a TNC client and a TNC server; the Network Authorization Transport Protocol Interface (IF-T) is an interface between a network access requestor and a network access authorizer; the Policy Enforcement Point Interface (IF-PEP) is an interface between a policy enforcement point and a network access authorizer; the Integrity Measurement Collector Interface (IF-IMC) is an interface between an integrity measurement collector and a TNC client; and the Integrity Measurement Verifier Interface (IF-IMV) is an interface between an integrity measurement verifier and a TNC server. 
     In the TCG-TNC architecture shown in  FIG. 1 , the access requestor does not evaluate the integrity of the policy enforcement point, hence, the policy enforcement point can not be relied upon. To solve this problem, a TNC architecture based on Tri-element Peer Authentication (TePA) has been proposed. The TePA-based TNC architecture is shown in  FIG. 2 . 
     In  FIG. 2 , the Integrity Measurement Interface (IF-IM) is an interface between an integrity measurement collector and an integrity measurement verifier; the TNC Client-TNC Access Point Interface (IF-TNCCAP) is an interface between a TNC client and a TNC access point; the Evaluation Policy Service Interface (IF-EPS) is an interface between a TNC access point and an evaluation policy server; the Trusted Network Transport Interface (IF-TNT) is an interface between a network access requestor and a network access controller; the Authentication Policy Service Interface (IF-APS) is an interface between a network access controller and an authentication policy server; the Integrity Measurement Collector Interface (IF-IMC) is between an integrity measurement collector and a TNC client, and between an integrity measurement collector and a TNC access point; and the Integrity Measurement Verifier Interface (IF-IMV) is an interface between an integrity measurement verifier and an evaluation policy server. 
     The TCG-TNC architecture shown in  FIG. 1  and the TePA-based TNC architecture shown in  FIG. 2  both require a platform authentication protocol to realize platform authentication (including platform credential authentication and integrity check handshake). However, due to the significant differences between the TePA-based TNC architecture shown in  FIG. 2  and the TCG-TNC architecture shown in  FIG. 1 , the platform authentication protocol for the TCG-TNC architecture is not suitable for the TePA-based TNC architecture shown in  FIG. 2 . Therefore, it is desired to design a platform authentication protocol suitable for the TePA-based TNC architecture shown in  FIG. 2 . 
     SUMMARY OF THE INVENTION 
     To solve the technical problems discussed in the BACKGROUND OF THE INVENTION, the present invention provides a platform authentication method suitable for a trusted network connect architecture based on tri-element peer authentication, which can improve network safety, facilitate centralized management and be beneficial for different deployments and implementations. 
     According to the present invention, it is provided a platform authentication method suitable for a trusted network connect architecture based on tri-element peer authentication, in which a TNC client, a TNC access point and an evaluation policy server perform a tri-element peer authentication protocol, including: 
     interacting with messages, between the TNC access point and the TNC client, to request for an integrity measurement value of each other&#39;s platform, and verify a platform signature on the integrity measurement value of each other&#39;s platform; and 
     interacting with messages, between the TNC access point and the evaluation policy server, so that the evaluation policy server verifies the validity of a platform identity certificate and evaluates the integrity measurement value. 
     The present invention may provide the following advantages. 
     1. Network safety can be improved. The platform authentication protocol for a TePA-based TNC architecture according to the present invention is a tri-element peer authentication protocol, which therefore can improve network safety in comparison with existing platform authentication protocols. 
     2. Centralized management can be facilitated. In the platform authentication protocol for a TePA-based TNC architecture according to the present invention, the policy manager acts as a trusted third party, which facilitates centralized management, and thus can improve manageability. 
     3. Different deployments and implementations can benefit. The platform authentication protocol for a TePA-based TNC architecture according to the present invention can be implemented in different ways, allowing different deployments and implementations. For example, the AIK certificate validity verification function may be implemented with a platform CA, and the evaluation of the integrity measurement value may be implemented with an evaluation server, both of which may be a trusted third party. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a structural diagram of an existing TCG-TNC architecture; 
         FIG. 2  is a structural diagram of an existing TePA-based TNC architecture; and 
         FIG. 3  illustrates a platform authentication protocol for a TePA-based TNC architecture according to the present invention with a structural diagram. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 3 , the present invention provides a platform authentication method suitable for a trusted network connect architecture based on tri-element peer authentication, which may be a tri-element peer authentication protocol performed by a TNC client, a TNC access point and an evaluation policy server. Specifically, the TNC client and the TNC access point request an integrity measurement value of each other&#39;s platform, the TNC client and the TNC access point verify only a platform signature of the integrity measurement value of each other&#39;s platform, and the validity of the platform identity certificates and the evaluation of the integrity measurement values are performed by the evaluation policy server. The platform identity certificate may be a platform Attestation Identity Key (AIK) certificate in the TCG-TNC architecture. The method may include the steps below. 
     1) The TNC access point generates an integrity measurement parameter for the access requester Parms C-AR  according to an evaluation policy, and then sends a message 1 to the TNC client. The message 1 may include a platform authentication activation challenge from the access controller N AC , an integrity measurement parameter for the access requester Parms C-AR , and another parameter Text1. 
     2) Upon receipt of the message 1, the TNC client sends firstly the integrity measurement parameter for the access requester Parms C-AR  to an IMC in the corresponding access requester, then the TNC client obtains an integrity measurement value of the access requester IntegrityInfo IMC-AR  (including PCR index data of the access requester PCRsIndex IMC-AR ) returned by the IMC in the access requester; if the integrity measurement value of the access requester IntegrityInfo IMC-AR  is unknowable to a trusted platform evaluation layer component (the encoding methods are different, or integrity measurement layer protection is enabled, e.g., a protection applied between an IMC in the access requester and an IMV in the policy manager), then the IMC in the access requester also needs to return PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR ; and finally, the TNC client sends a message 2 to the access controller, and the message 2 may include the integrity measurement value of the access requester IntegrityInfo IMC-AR , the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , a platform authentication request challenge from the access requester N AR , an integrity measurement parameter for the access controller Parms C-AC , an evaluation policy for the integrity measurement value of the access controller Evals C-AC , and another parameter Text2. The integrity measurement value of the access requester IntegrityInfo IMC-AR  may be an integrity measurement layer message, and may be in the integrity report format or the IF-M message format as in the TCG-TNC architecture (it may be provided with a protection between the access requester and the policy manager, or may also be provided with a protection between the IMC in the access requester and the IMV in the policy manager). The PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR  may be in the QuoteData format in an integrity report as in the TCG-TNC architecture. 
     3) Upon receipt of the message 2, the TNC access point verifies firstly a platform signature in the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , e.g., AIK signature, and if the verification fails, then the message is discarded, otherwise, the TNC access point sends the integrity measurement parameter for the access controller Parms C-AC  to the IMC in the corresponding access controller, and obtains the integrity measurement value of the access controller IntegrityInfo IMC-AC  (including the PCR index data of the access controller PCRsIndex IMC-AC ) returned by the IMC in the access controller; if the integrity measurement value of the access controller IntegrityInfo IMC-AC  is unknowable to a trusted platform evaluation layer component, e.g., the encoding methods may be different or integrity measurement layer protection may be enabled, which may be a protection applied between the IMC in the access controller and the IMV in the policy manager, then the IMC in the access controller also needs to return the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC ; and finally, the TNC access point sends a message 3 to the evaluation policy server, and the message 3 may include a platform authentication verification challenge from the access controller N AC-PM , a platform authentication request challenge from the access requester N AR , an AIK certificate of the access requester Cert AIK-AR , an AIK certificate of the access controller Cert AIK-AC , an integrity measurement value of the access requester IntegrityInfo IMC-AR , an integrity measurement value of the access controller IntegrityInfo IMC-AC , an integrity measurement parameter for the access requester that is actually measured Parms PC-AR , an evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , integrity measurement parameter for the access controller that is actually measured Parms PC-AC , an evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , and another parameter Text3. The integrity measurement value of the access controller IntegrityInfo IMC-AC  may be an integrity measurement layer message, and may be in the integrity report format or the IF-M message format as in the TCG-TNC architecture (it may be provided with a protection between the access controller and the policy manager, or may also be provided with a protection between the IMC in the access controller and the IMV in the policy manager). The integrity measurement parameter for the access requester that is actually measured Parms PC-AR , is the part of the integrity measurement parameter for the access requester Parms C-AR  that has been measured and is determined according to a message type in the encapsulation of the integrity measurement value of the access requester IntegrityInfo IMC-AR . The evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , is generated according to a message type in the encapsulation of the integrity measurement value of the access requester IntegrityInfo IMC-AR  as well as a local evaluation policy, and the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR  may be provided with a protection between the access controller and the policy manager. The integrity measurement parameter for the access controller that is actually measured Parms PC-AC , is the part of the integrity measurement parameter for the access controller Parms C-AC  that has been measured and is determined according to a message type in the encapsulation of the integrity measurement value of the access controller IntegrityInfo IMC-AC . The evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , is the part of the evaluation policy for the integrity measurement value of the access controller Evals C-AC  that has been measured and is determined according to a message type in the encapsulation of the integrity measurement value of the access controller IntegrityInfo IMC-AC . 
     4) Upon receipt of the message 3, the evaluation policy server may process the message 3 in one of the following two manners and sends a message 4 to the TNC access point. 
     a) First manner, where the verification of the validity of the AIK certificate and the evaluation of the integrity measurement value both are performed in a centralized manner. 
     a.1) The evaluation policy server verifies the validity of the AIK certificate of the access requester Cert AIK-AR  and generates an AIK certificate verification result for the access requester Re AIK-AR , and the evaluation policy server verifies the validity of the AIK certificate of the access controller Cert AIK-AC  and generates an AIK certificate verification result for the access controller Re AIK-AC . 
     a.2) If the AIK certificate of the access requester Cert AIK-AR  is valid, then the evaluation policy server firstly sets, according to the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , an IMV in a corresponding policy manager; secondly, the evaluation policy server sends the integrity measurement value of the access requester IntegrityInfo IMC-AR  to the IMV in the policy manager in which the evaluation policy is set; next the IMV in the policy manager in which the evaluation policy is set evaluates the integrity measurement value of the access requester IntegrityInfo IMC-AR  and returns a component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and component-level fault information for the integrity measurement value of the access requester Faults IMV-AR . They are integrity measurement layer information, and may be provided with protections between the access requester and the policy manager, as well as protections between the IMC in the access requester and the IMV in the policy manager. If the integrity measurement value of the access requester IntegrityInfo IMC-AR  is unknowable to a trusted platform evaluation layer component (the encoding methods are different or integrity measurement layer protection is enabled, e.g., a protection applied between an IMC in the access requester and an IMV in the policy manager), then the IMV in the policy manager in which the evaluation policy is set also needs to return PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR ; and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR  is unknowable to a trusted platform evaluation layer component, then the IMV in the policy manager in which the evaluation policy is set also needs to return a component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR . 
     a.3) If the AIK certificate of the access controller Cert AIK-AC  is valid, then the evaluation policy server firstly sets, according to the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , an IMV in a corresponding policy manager; secondly, the evaluation policy server sends the integrity measurement value of the access controller IntegrityInfo IMC-AC  to the IMV in the policy manager in which the evaluation policy is set; next the IMV in the policy manager in which the evaluation policy is set evaluates the integrity measurement value of the access controller IntegrityInfo IMC-AC  and returns a component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and component-level fault information for the integrity measurement value of the access controller Faults IMV-AC . They are integrity measurement layer information, and may be provided with protections between the access controller and the policy manager, as well as protections between the IMC in the access controller and the IMV in the policy manager. If the integrity measurement value of the access controller IntegrityInfo IMC-AC  is unknowable to a trusted platform evaluation layer component (the encoding methods are different or integrity measurement layer protection is enabled, for example, a protection between the IMC in the access controller and the IMV in the policy manager), then the IMV in the policy manager in which the evaluation policy is set also needs to return PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC ; and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC  is unknowable to a trusted platform evaluation layer component, then the IMV in the policy manager in which the evaluation policy is set also needs to return a component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC . 
     a.4) The signatures on the verification result of the validity of the AIK certificate and on the evaluation result of the integrity measurement value may be signed in a centralized manner, or may be signed in a separate manner. 
     a.4.1) In the separated case, the evaluation policy server sends a message 4 to the TNC access point, and the message 4 may include the AIK certificate verification result for the access requester Re AIK-AR , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the AIK certificate verification result for the access controller Re AIK-AC , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , a separate signature 1 Sig1 PM , a separate signature 2 Sig2 PM , and a parameter Text4. The separate signature 1 Sig1 PM  is a signature signed by the policy manager by using a private key corresponding to its user certificate on the platform authentication verification challenge from the access controller N AC-PM , the platform identity certificate of the access requester Cert AIK-AR , the platform identity certificate verification result for the access requester Re AIK-AR , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , and a parameter Text7. The separate signature 2 Sig2 PM  is a signature signed by the policy manager by using the private key corresponding to its user certificate on the platform authentication request challenge from the access requester N AR , the platform identity certificate of the access controller Cert AIK-AC , platform identity certificate verification result for the access controller Re AIK-AC , integrity measurement parameter for the access controller that is actually measured Parms PC-AC , evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , and a parameter Text8. If the platform identity certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if the platform identity certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     a.4.2) In the centralized case, the evaluation policy server sends a message 4 to the TNC access point, and the message 4 may include the AIK certificate verification result for the access requester Re AIK-AR , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the AIK certificate verification result for the access controller Re AIK-AC , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , a separate signature Sig PM , and another parameter Text4. The separate signature Sig PM  is a signature signed by a policy manager by using the private key corresponding to its user certificate on the platform authentication verification challenge from the access controller N AC-PM , the AIK certificate of the access requester Cert AIK-AR , the AIK certificate verification result for the access requester Re AIK-AR , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the platform authentication request challenge from the access requester N AR , the AIK certificate of the access controller Cert AIK-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , and another parameter Text7. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if the AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist; 
     b) Second manner, where the validity of the verification of the platform identity certificate and the evaluation of the integrity measurement value are performed in a separate manner. 
     b.1) The evaluation policy server verifies the validity of the AIK certificate of the access requester Cert AIK-AR  and generates an AIK certificate verification result for the access requester Re AIK-AR , and the evaluation policy server verifies the validity of the AIK certificate of the access controller Cert AIK-AC  and generates an AIK certificate verification result for the access controller Re AIK-AC . 
     b.2) The signatures on the verification result of the validity of the AIK certificate may be signed in a centralized manner, or may be signed in a separate manner. 
     b.2.1) In the separated case, the AIK certificate validity verification part of the message 4 may include the AIK certificate verification result for the access requester Re AIK-AR , the AIK certificate verification result for the access controller Re AIK-AC , a certificate validity verification separate signature 1 Sig1 PM-AIK , and a certificate validity verification separate signature 2 Sig2 PM-AIK . The certificate validity verification separate signature 1 Sig1 PM-AIK  is a signature signed by using the private key corresponding to the user certificate on the platform authentication verification challenge from the access controller N AC-PM , the AIK certificate of the access requester Cert AIK-AR , the AIK certificate verification result for the access requester Re AIK-AR , and a Text7. The certificate validity verification separate signature 2 Sig2 PM-AIK  is a signature signed by using the private key corresponding to the user certificate on the platform authentication request challenge from the access requester N AR , the AIK certificate of the access controller Cert AIK-AC , the AIK certificate verification result for the access controller Re AIK-AC , and a Text8. 
     b.2.2) In the centralized case, the AIK certificate validity verification of the message 4 may include the AIK certificate verification result for the access requester Re AIK-AR , the AIK certificate verification result for the access controller Re AIK-AC , and a certificate validity verification separate signature Sig PM-AIK . The certificate validity verification separate signature Sig PM-AIK  is a signature signed by using the private key corresponding to the user certificate on the platform authentication verification challenge from the access controller N AC-PM , the AIK certificate of the access requester Cert AIK-AR , the AIK certificate verification result for the access requester Re AIK-AR , the platform authentication request challenge from the access requester N AR , the AIK certificate of the access controller Cert AIK-AC , the AIK certificate verification result for the access controller Re AIK-AC , and a Text7. 
     b.3) If the AIK certificate of the access requester Cert AIK-AR  is valid, then the evaluation policy server firstly sets, according to the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , an IMV in a corresponding policy manager; secondly, the evaluation policy server sends the integrity measurement value of the access requester IntegrityInfo IMC-AR  to the IMV in the policy manager in which the evaluation policy is set; next the IMV in the policy manager in which the evaluation policy is set evaluates the integrity measurement value of the access requester IntegrityInfo IMC-AR  and returns a component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and component-level fault information for the integrity measurement value of the access requester Faults IMV-AR . They are integrity measurement layer information, and may be provided with protections between the access requester and the policy manager, as well as protections between the IMC in the access requester and the IMV in the policy manager. If the integrity measurement value of the access requester IntegrityInfo IMC-AR  is unknowable to a trusted platform evaluation layer component (the encoding methods are different or integrity measurement layer protection is enabled, e.g., a protection applied between an IMC in the access requester and an IMV in the policy manager), then the IMV in the policy manager in which the evaluation policy is set also needs to return PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR ; if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR  is unknowable to a trusted platform evaluation layer component, then the IMV in the policy manager in which the evaluation policy is set also needs to return a component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR . 
     b.4) If the AIK certificate of the access controller Cert AIK-AC  is valid, then the evaluation policy server firstly sets, according to the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , an IMV in a corresponding policy manager; secondly, the evaluation policy server sends the integrity measurement value of the access controller IntegrityInfo IMC-AC  to the IMV in the policy manager in which the evaluation policy is set; next the IMV in the policy manager in which the evaluation policy is set evaluates the integrity measurement value of the access controller IntegrityInfo IMC-AC  and returns a component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , They are integrity measurement layer information, and may be provided with protections between the access controller and the policy manager, as well as protections between the IMC in the access controller and the IMV in the policy manager. If the integrity measurement value of the access controller IntegrityInfo IMC-AC  is unknowable to a trusted platform evaluation layer component (the encoding methods are different or integrity measurement layer protection is enabled, for example, a protection applied between the IMC in the access controller and the IMV in the policy manager), then the IMV in the policy manager in which the evaluation policy is set also needs to return PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC ; if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC  is unknowable to a trusted platform evaluation layer component, then the IMV in the policy manager in which the evaluation policy is set also needs to return a component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC . 
     b.5) The signatures on the evaluation result of the integrity measurement value may be signed in a centralized manner or in a separate manner. 
     b.5.1) In the separated case, the integrity measurement value evaluation part of the message 4 may include the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , an integrity measurement value evaluation separate signature 1 Sig1 PM-IM , and an integrity measurement value evaluation separate signature 2 Sig2 PM-IM . The integrity measurement value evaluation separate signature 1 Sig1 PM-IM  is a signature signed by the policy manager by using the private key corresponding to its user certificate on the platform authentication verification challenge from the access controller N AC-PM , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res&#39; IMV-AR , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , and another parameter Text9. The integrity measurement value evaluation separate signature 2 Sig2 PM-IM  is a signature signed by the policy manager by using the private key corresponding to its user certificate on the platform authentication request challenge from the access requester N AR , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , and another parameter Text10. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if the platform identity certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     b.5.2) In the centralized case, the integrity measurement value evaluation part of the message 4 may include the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , and an integrity measurement value evaluation separate signature Sig PM-IM . The integrity measurement value evaluation separate signature Sig PM-IM  is a signature signed by the policy manager by using the private key corresponding to its user certificate on the platform authentication verification challenge from the access controller N AC-PM , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res&#39; IMV-AR , the platform authentication request challenge from the access requester N AR , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC , and another parameter Text9. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if the platform identity certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     b.6) The evaluation policy server sends message 4 to the TNC access point, and the message 4 may include the AIK certificate validity verification part of the message 4, the integrity measurement value evaluation part of the message 4, and another parameter Text4. 
     5) Upon receipt of the message 4, the TNC access point may perform the following processes. 
     c) If the message 4 received by the TNC access point is the message 4 sent in the step a.4.1), then the following processes will be performed. 
     c.1) The TNC access point verifies the validity of the separate signature 1 Sig1 PM , and the message is discarded if the separate signature 1 Sig1 PM  is invalid. 
     c.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates, according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR  in each round of the platform authentication protocol during the platform authentication, an access decision for the access controller Action AC  (which indicates allowed/blocked/isolated, and may include the reason for this access decision), and sends the Action AC  to the network access controller. If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the platform identity certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     c.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     c.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the separate signature 2 Sig2 PM  and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     d) If the message 4 received by the TNC access point is the message 4 sent in the step a.4.2), then the following processes will be performed. 
     d.1) The TNC access point verifies the validity of the separate signature Sig PM , and the message is discarded if the separate signature Sig PM  is invalid. 
     d.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates an access decision for the access controller Action AC  according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access controller Action AC  to the network access controller (which indicates allowed/blocked/isolated, and may include the reason for this access decision). If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     d.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     d.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the platform identity certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the platform authentication verification challenge from the access controller N AC-PM , the platform identity certificate verification result for the access requester Re AIK-AR , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the separate signature Sig PM  and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     e) If the message 4 received by the TNC access point is the message 4 sent in the step b.6), and if the signatures in both the AIK certificate validity verification part and the integrity measurement value evaluation part are signed in a separate manner, then the following processes are performed. 
     e.1) The TNC access point verifies the validity of the certificate validity verification separate signature 1 Sig1 PM-AIK  and the integrity measurement value evaluation separate signature 1 Sig1 PM-IM , and the message is discarded if invalid. 
     e.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates the access decision for the access controller Action AC  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access controller Action AC  to the network access controller. If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     e.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     e.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the certificate validity verification separate signature 2 Sig2 PM-AIK , the integrity measurement value evaluation separate signature 2 Sig2 PM-IM , and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     f) If the message 4 received by the TNC access point is the message 4 sent in the step b.6), and if the signatures in both the AIK certificate validity verification part and the integrity measurement value evaluation part are signed in a centralized manner, the following processes are performed. 
     f.1) The TNC access point verifies the validity of the certificate validity verification separate signature Sig PM-AIK  and the integrity measurement value evaluation separate signature Sig PM-IM , and the message is discarded if invalid. 
     f.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates the access decision for the access controller Action AC  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res&#39; IMV-AR  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access controller Action AC  to the network access controller. If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     f.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     f.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the platform authentication verification challenge from the access controller N AC-PM , the AIK certificate verification result for the access requester Re AIK-AR , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the certificate validity verification separate signature Sig PM-AIK , the integrity measurement value evaluation separate signature Sig PM-IM , and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     g) If the message 4 received by the TNC access point is the message 4 sent in the step b.6), and if the signatures in the AIK certificate validity verification part are signed in a separate manner and the signatures in the integrity measurement value evaluation part are signed in a centralized manner, then the following processes are performed. 
     g.1) The TNC access point verifies the validity of the certificate validity verification separate signature 1 Sig1 PM-AIK  and the integrity measurement value evaluation separate signature Sig PM-IM , and the message is discarded if invalid. 
     g.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates the access decision for the access controller Action AC  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res&#39; IMV-AR  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access controller Action AC  to the network access controller. If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     g.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     g.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the platform authentication verification challenge from the access controller N AC-PM , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , the certificate validity verification separate signature 2 Sig2 PM-AIK , the integrity measurement value evaluation separate signature Sig PM-IM , and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     h) If the message 4 received by the TNC access point is the message 4 sent in the step b.6), and if the signatures in the AIK certificate validity verification part are signed in a centralized manner and the signatures in the integrity measurement value evaluation part are signed in a separate manner, then the following processes are performed. 
     h.1) The TNC access point verifies the validity of the certificate validity verification separate signature Sig PM-AIK  and the integrity measurement value evaluation separate signature 1 Sig1 PM-IM , and the message is discarded if invalid. 
     h.2) If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is valid, then firstly it is verified whether the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access requester that is actually measured Parms PC-AR  and the integrity measurement parameter for the access requester Parms C-AR , otherwise, the TNC access point generates the access decision for the access controller Action AC  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access controller Action AC  to the network access controller. If the AIK certificate verification result for the access requester Re AIK-AR  indicates that the AIK certificate of the access requester Cert AIK-AR  is invalid, then the TNC access point generates the access decision for the access controller Action AC  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access controller Action AC  to the network access controller. 
     h.3) If the access decision for the access controller Action AC  is not BLOCK or the access decision for the access controller Action AC  has not been generated, and if the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  exist and are not NULL, then the TNC access point sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access controller Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  to the corresponding IMC in the access controller. 
     h.4) The TNC access point sends a message 5 to the TNC client, and the message 5 may include the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the AIK certificate verification result for the access controller Re AIK-AC , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC , the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the access decision for the access controller Action AC , the platform authentication verification challenge from the access controller N AC-PM , the AIK certificate verification result for the access requester Re AIK-AR , the certificate validity verification separate signature Sig PM-AIK , the integrity measurement value evaluation separate signature 2 Sig2 PM-IM , and another parameter Text5. If the AIK certificate of the access requester Cert AIK-AR  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access requester are set to be NULL or not exist; and if AIK certificate of the access controller Cert AIK-AC  is invalid, then the parameters related to the evaluation of the integrity measurement value of the access controller are set to be NULL or not exist. 
     6) Upon receipt of the message 5, the TNC client performs the following processes. 
     i) If the message 5 received by the TNC client is the message 5 sent in the step c.4), the following processes are performed. 
     i.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed, and generates an access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, the step i.2) is performed. 
     i.2) The TNC client verifies the validity of the separate signature 2 Sig2 PM , if invalid, then the message is discarded. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise, the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     i.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     i.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     j) If the message 5 received by the TNC client is the message 5 sent in the step d.4), the following processes are performed. 
     j.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed and generates an access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, then step j.2) is performed. 
     j.2) The TNC client verifies the validity of the separate signature Sig PM , and the message is discarded if invalid. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise, the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     j.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     j.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     k) If the message 5 received by the TNC client is the message 5 sent in the step e.4), the following processes are performed. 
     k.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed and generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, the step k.2) is performed. 
     k.2) The TNC client verifies the validity of the certificate validity verification separate signature 2 Sig2 PM-AIK  and the integrity measurement value evaluation separate signature 2 Sig2 PM-IM , if invalid, then the message is discarded. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     k.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     k.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     l) If the message 5 received by the TNC client is the message 5 sent in the step f.4), the following processes are performed. 
     l.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed, and generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, the step l.2) is performed. 
     l.2) The TNC client verifies the validity of the certificate validity verification separate signature Sig PM-AIK  and the integrity measurement value evaluation separate signature Sig PM-IM , and the message is discarded if invalid. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise, the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     l.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then by the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     l.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     m) If the message 5 received by the TNC client is the message 5 sent in the step g.4), the following processes are performed. 
     m.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed, and generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, the step m.2) is performed. 
     m.2) The TNC client verifies the validity of the certificate validity verification separate signature 2 Sig2 PM-AIK  and the integrity measurement value evaluation separate signature Sig PM-IM , and the message is discarded if invalid. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise, the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     m.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     m.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     n) If the message 5 received by the TNC client is the message 5 sent in the step h.4), the following processes are performed. 
     n.1) If the access decision for the access controller Action AC  is BLOCK, then the TNC client notifies the IMC in the access requester that platform remediation is not needed, and generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the access controller blocks the access) and sends the access decision for the access requester Action AR  to the network access requester; otherwise, the step n.2) is performed. 
     n.2) The TNC client verifies the validity of the certificate validity verification separate signature Sig PM-AIK  and the integrity measurement value evaluation separate signature 2 Sig2 PM-IM , and the message is discarded if invalid. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is valid, then firstly it is verified whether the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC  are the same, and if not the same, then another around of the platform authentication protocol may be executed by using the difference between the integrity measurement parameter for the access controller that is actually measured Parms PC-AC  and the integrity measurement parameter for the access controller Parms C-AC , otherwise, the TNC access point generates the access decision for the access requester Action AR  (which indicates allowed/blocked/isolated, and may include the reason for this access decision) according to the component-level evaluation result for the integrity measurement value of the access controller knowable to a trusted platform evaluation layer component Res′ IMV-AC  in each round of the platform authentication protocol during the platform authentication, and sends the access decision for the access requester Action AR  to the network access requester. If the AIK certificate verification result for the access controller Re AIK-AC  indicates that the AIK certificate of the access controller Cert AIK-AC  is invalid, then the TNC client generates the access decision for the access requester Action AR  (the result is BLOCK, and the reason for this access decision is that the AIK certificate is invalid) and sends the access decision for the access requester Action AR  to the network access requester. 
     n.3) If the access decision for the access requester Action AR  is not BLOCK or the access decision for the access requester Action AR  has not been generated by the TNC client, and if the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  exist and are not NULL, then the TNC client sends, according to the message type, the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  to the corresponding IMC in the access request; and if the access decision for the access controller Action AC  is not NULL, then the TNC client notifies the IMC in the access requester of the access decision for the access controller Action AC . 
     n.4) When the TNC client has generated the access decision for the access requester Action AR , it sends a message 6 to the TNC access point. The message 6 may include the platform authentication activation challenge from the access controller N AC , the access decision of the access requester Action AR , and another parameter Text6. 
     7) Upon receipt of the message 6, if the access decision for the access requester Action AR  is BLOCK, then the TNC access point notifies the IMC in the access controller that platform remediation is not needed; if the access decision for the access requester Action AR  is ISOLATE, then the TNC access point notifies the IMC in the access controller that platform remediation is needed. 
     In the platform authentication protocol according to the present invention, the messages between the TNC client and the TNC access point are transmitted in a secure channel between the access requester and the access controller. As a matter of course, the platform authentication protocol according to the present invention may be a two-way authentication protocol, or, may also be applied in one-way authentication. When it is applied in one-way authentication, the parameters related to the authentication in the other direction may be set to be NULL or not exist. The platform authentication method suitable for a trusted network connect architecture based on tri-element peer authentication may be implemented without the verification of the validity of the AIK certificate, for example, in a platform authentication process, after the first round of the platform authentication protocol, other rounds of the platform authentication protocol can be performed without the verification of the validity of the AIK certificate, with the parameters related to the verification of the validity of the AIK certificate set to be NULL or not exist. 
     The integrity measurement layer message can provide a protection between the integrity measurement collector and the integrity measurement verifier. If the IMV in the policy manager is implemented remotely, then a protection needs to be provided between the evaluation policy server and the IMV in the policy manager; the integrity measurement value of the access requester IntegrityInfo IMC-AR , the evaluation policy for the integrity measurement value of the access controller Evals C-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , and the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR  may be provided with a protection between the access requester and the policy manager; and the integrity measurement value of integrity measurement value of the access controller IntegrityInfo IMC-AC , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  may be provided with a protection between the access controller and the policy manager. 
     The integrity measurement parameter for the access requester Parms C-AR , the integrity measurement parameter for the access controller Parms PC-AC , the evaluation policy for the integrity measurement value of the access controller Evals C-AC , the integrity measurement parameter for the access requester that is actually measured Parms PC-AR , the evaluation policy for the integrity measurement value of the access requester that is actually measured Evals PC-AR , the integrity measurement parameter for the access controller that is actually measured Parms PC-AC , and the evaluation policy for the integrity measurement value of the access controller that is actually measured Evals PC-AC  may be encapsulated in the format below: 
     
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 Message type 
                 Integrity measurement parameter list 
                 Evaluation 
               
               
                   
                   
                 policy list 
               
               
                 Message type 
                 Integrity measurement parameter list 
                 Evaluation 
               
               
                   
                   
                 policy list 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                   
               
             
          
         
       
     
     The integrity measurement value of the access requester IntegrityInfo IMC-AR , the integrity measurement value of the access controller IntegrityInfo IMC-AC , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AR , the component-level remediation information for the integrity measurement value of the access requester Rems IMV-AR , the component-level fault information for the integrity measurement value of the access requester Faults IMV-AR , the component-level evaluation result for the integrity measurement value of the access requester Res IMV-AC , the component-level remediation information for the integrity measurement value of the access controller Rems IMV-AC , and the component-level fault information for the integrity measurement value of the access controller Faults IMV-AC  all are integrity measurement layer messages, and their encapsulation format in the trusted platform evaluation layer may be as shown below: 
     
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 Message 
                 Integrity measurement collector 
                 Integrity measurement layer 
               
               
                 type 
                 identify 
                 message 
               
               
                 Message 
                 Integrity measurement collector 
                 Integrity measurement layer 
               
               
                 type 
                 identify 
                 message 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                   
               
             
          
         
       
     
     The PCR index data of the access requester knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AR , the PCR index data of the access controller knowable to a trusted platform evaluation layer component PCRsIndex′ IMC-AC , the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AR , and the component-level evaluation result for the integrity measurement value of the access requester knowable to a trusted platform evaluation layer component Res′ IMV-AC  may be encapsulated in the format below: 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Message 
                 PCR index data or component-level evaluation 
               
               
                   
                 type 
                 result knowable to a trusted platform evaluation 
               
               
                   
                   
                 layer component 
               
               
                   
                 Message 
                 PCR index data or component-level evaluation 
               
               
                   
                 type 
                 result knowable to a trusted platform evaluation 
               
               
                   
                   
                 layer component 
               
               
                   
                 . . . 
                 . . . 
               
               
                   
                   
               
             
          
         
       
     
     The embodiments of the present application disclosed herein shall not be interpreted as limiting the scope of protection of the present application. Any modifications, equivalents, improvements and the like within the scope of the present invention shall fall within the scope of protection of the present invention.