# Patent

## Title
Method for authenticating a trusted platform based on the tri-element peer authentication(TEPA)

## Abstract

A method for authenticating a trusted platform based on the Tri-element Peer Authentication (TePA). The method includes the following steps: A) a second attesting system sends the first message to a first attesting system; B) the first attesting system sends a second message to the second attesting system after receiving the first message; C) the second attesting system sends a third message to a Trusted Third Party (TTP) after receiving the second message; D) the TTP sends a fourth message to the second attesting system after receiving the third message; E) the second attesting system sends a fifth message to the first attesting system after receiving the fourth message; and F) the first attesting system performs an access control after receiving the fifth message. The method for authenticating a trusted platform based on TePA of the present invention adopts the security architecture of TePA, and improves the safety of an evaluation agreement of the trusted platform, realizes the mutual evaluation of the trusted platform between the attesting systems, and extends the application ranges.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Chinese Patent Application no. 200810232093.5, filed with the Chinese Patent Office on Nov. 4, 2008 and entitled “Trustworthy Platform Verification Method Based On Tri-element Peer Authentication (TePA)”, which is hereby incorporated by reference in its entirety.
This application is a 371 U.S. National Stage of International Application No. PCT/CN2009/074763, filed Nov. 3, 2009. This application claims the benefit of Chinese Patent Application No. 200810232093.5, filed Nov. 4, 2008. The disclosures of the above applications are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a trustworthy platform verification method based on tri-element Peer Authentication (TePA).
BACKGROUND OF THE INVENTION
The issue of network security has been challenged severely along with gradual development of computer network. Existing security solutions in the field tend to be focused on preventing the hazards from the outside firstly and then from the inside, that is, firstly preventing the hazards from a service facility and then from a terminal facility. However, trusted computing runs to the contrary by firstly ensuring security of all terminals, that is, by building a larger security system through ensuring secured components. Higher-level precaution is taken at an underlying layer of a trusted computing platform, and an enhanced protection space and scope of selections can be provided for users by preventing a soft-level attack through trustworthy hardware.
A Challenger (CH) has to evaluate the trusted computing platform by a certain platform attribute to verify trustworthiness of the trusted computing platform. In trusted computing specification established by the Trusted Computing Group (TCG), the Challenger CH evaluates the trusted computing platform by platform integrity, where the evaluated trusted computing platform is referred to an Attesting System (AS), and FIG. 1 illustrates a corresponding trusted platform evaluation protocol as follows:
1) The Challenger CH generates a random number NCH and transmits a message 1=NCH to the Attesting System AS.
2) Upon reception of the message 1, the Attesting System AS firstly transports the random number NCH to a Trusted Platform Module (TPM) thereof and then extracts Platform Configuration Register values PCRsAS of the Attesting System AS by the Trusted Platform Module TPM of the Attesting System AS, extracts the measurement logs LogAS corresponding to the Platform Configuration Register values PCRsAS of the Attesting System AS from the Store Measurement Log (SML) of the Attesting System AS using a signature [PCRsAS, NCH]Sig performed with a private key of an Attesting Identity Key (AIK) of the Attesting System AS on the Platform Configuration Register values PCRsAS of the Attesting System AS and the random number NCH, and finally transmits a message 2=PCRsAS∥LogAS∥[PCRsAS, NCH]Sig to the Challenger CH, where ∥ represents concatenation of character strings.
3) Upon reception of the message 2, the Challenger CH firstly verifies the signature against a public key of the Attesting Identity Key AIK of the Attesting System AS, the random number NCH and the Platform Configuration Register values PCRsAS of the Attesting System AS in the message 2 and discards the message 2 if the signature is invalid, otherwise verifies correctness of the measurement logs LogAS corresponding to the Platform Configuration Register values PCRsAS of the Attesting System AS in the message 2 against the Platform Configuration Register values PCRsAS of the Attesting System AS in the message 2 and terminates the protocol process if it is incorrect, otherwise verifies trustworthiness of the Attesting System AS against the measurement logs LogAS corresponding to the Platform Configuration Register values PCRsAS of the Attesting System AS in the message 2 and reference integrity values of respective components in the measurement logs LogAS.
In the foregoing trusted platform evaluation protocol, messages exchanged between the Attesting System AS and the Challenger CH are transmitted over a secure channel. As can be apparent from the trusted platform evaluation protocol illustrated in FIG. 1, this protocol is applicable only to unidirectional trusted platform evaluation, and the Challenger CH has to be capable of verifying the Attesting Identity Key AIK and platform integrity of the Attesting System AS, where the Challenger CH can verify the Attesting Identity Key AIK of the Attesting System AS based upon Trusted Third Party (TTP) or through Direct Anonymous Attestation (DAA). When Attesting Systems AS have to be mutually verified trustworthiness of opposite platform, however, if one of the Attesting Systems AS is incapable of verifying the Attesting Identity Key AIK and platform integrity of the opposite Attesting System AS, then the Attesting Identity Key AIK and platform integrity of the Attesting System AS can not be verified in the prior art.
SUMMARY OF THE INVENTION
In order to address the foregoing technical problem in the prior art, the invention provides a method for verifying an Attesting Identity Key AIK and platform integrity of an Attesting System AS through a Trusted Third Party TTP, i.e., a trusted platform verification method based on Tri-element Peer Authentication (TePA).
In a technical solution of the invention, the invention is a trusted platform verification method based on Tri-element Peer Authentication, wherein the method includes the steps of:

    
    
        A) transmitting, by a second Attesting System, a first message to a first Attesting System, wherein the first message includes a random number NAS2 generated by the second Attesting System, an Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System and a parameter list ParmPCRs-AS1 of Platform Configuration Register values PCRs requested by the second Attesting System from the first Attesting System;
        B) transporting, by the first Attesting System, the NAS2 to a Trusted Platform Module TPM of the first Attesting System, and then extracting corresponding Platform Configuration Register values PCRsAS1 from the Trusted Platform Module TPM based on the parameter list ParmPCRs-AS1 of PCRs, performing a signature [NAS2, PCRsAS1]Sig on the PCRsAS1 and the NAS2 using a private key of an Attesting Identity Key AIK of the first Attesting System, extracting the measurement logs LogAS1 corresponding to the PCRsAS1 from the Store Measurement Log SML of the first Attesting System, and transmitting a second message to the second Attesting System AS2, wherein the second message includes a random number NAS1 generated by the first Attesting System, an Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System and a parameter list ParmPCRs-AS2 of Platform Configuration Register values PCRs requested by the first Attesting System from the second Attesting System;
        C) verifying, by the second Attesting System, the signature against a public key of the Attesting Identity Key AIK certificate of the first Attesting System, the NAS2 and the PCRsAS1, and if the signature is invalid, then discarding the second message; otherwise, transmitting the NAS1 to a Trusted Platform Module TPM of the second Attesting System, extracting from the Trusted Platform Module TPM of the second Attesting System corresponding Platform Configuration Register values PCRsAS2 against the ParmPCRs-AS2, performing a signature [NAS1, PCRsAS2]Sig on the PCRsAS2 and the NAS1 using a private key of an Attesting Identity Key AIK of the second Attesting System, extracting the measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRsAS2 from the Store Measurement Log SML of the second Attesting System, and transmitting to a Trustworthy Third Party TTP a third message including an authentication random number NAS2-TTP generated by the second Attesting System;
        D) verifying, by the Trusted Third Party TTP, validity of the CertAIK-AS1 and the CertAIK-AS2, generating a verification result ReAIK-AS1 of the CertAIK-AS1 and a verification result ReAIK-AS2 of the CertAIK-AS2, and then verifying correctness of the
    
    


LogAS1 against the PCRsAS1, and if it is incorrect, then discarding the message; otherwise, verifying the correctness of LogAS2 against the PCRsAS2, and if it is incorrect, then discarding the message; otherwise, evaluating trustworthiness of the first Attesting System against the LogAS1 and reference integrity values of respective components in the LogAS1 and trustworthiness of the second Attesting System against the LogAS2 and reference integrity values of respective components in the LogAS2, generating a platform integrity verification result RePCRs-AS1 and platform remediation information RemAS1 of the first Attesting System and a platform integrity verification result RePCRs-AS2 and platform remediation information RemAS2 of the second Attesting System, calculating relevant parameters of the first Attesting System AS1 and the second Attesting System AS2 from the private keys and transmitting a fourth message including the relevant parameters to the AS2;

    
    
        E) verifying, by the second Attesting System, the signature against the fourth message, and if the signature is invalid, then discarding the message; otherwise, generating a result of the AS1 accessing the AS2 and transmitting a fifth message to the first Attesting System AS1; and
        F) verifying, by the AS1, the signature against the fifth message, and if the signature is invalid, then discarding the message; otherwise, verifying the signature in the fourth message, and if the signature is invalid, then terminating the protocol process; otherwise, performing access control against the verification result ReAIK-AS2 of the CertAIK-AS2, the platform integrity verification result RePCRs-As2 of the second Attesting System AS2 and the result Reaccess of the first Attesting System AS1 accessing the second Attesting System AS2.
    
    


The list of Platform Configuration Registers PCR in the step A) is a list of Platform Configuration Registers PCR determined in the first Attesting System or a list of components determined in the first Attesting System.
The list of Platform Configuration Registers PCR in the step B) is a list of Platform Configuration Registers PCR determined in the second Attesting System or a list of components determined in the second Attesting System.
The messages exchanged between the first Attesting System and the second Attesting System are transported over a secure channel therebetween.
The messages exchanged between the second Attesting System and the Trusted Third Party are transported over a secure channel therebetween.
If the second Attesting System can not know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based upon Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message includes the CertAIK-AS1 and the verification result ReAIK-AS1, the CertAIK-AS2 and the verification result ReAIK-AS2.
The invention has the following advantages:
1) The trusted platform verification method based on Tri-element Peer Authentication according to the invention performs bidirectional trusted platform evaluation between the Attesting Systems, verifies the Attesting Identity Keys AIK and platform integrity of the Attesting Systems AS through a Trusted Third Party TTP to thereby extend the application scope.
2) The trusted platform verification method based on Tri-element Peer Authentication according to the invention adopts security architecture of Tri-element Peer Authentication and enhances security of the trusted platform evaluation protocol.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a trusted platform verification method in a TCG architecture in the prior art; and
FIG. 2 illustrates a schematic diagram of the method according to the invention.



DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 2, the invention particularly includes the following steps:
1) A second Attesting System AS2 transmits a first message to a first Attesting System AS1, wherein the first message includes a random number generated by the second Attesting System, an Attesting Identity Key AIK certificate of the second Attesting System and a parameter list of Platform Configuration Register values PCRs requested by the second Attesting System from the first Attesting System.
Particularly, the first message (message 1)=NAS2∥CertAIK-AS2∥ParmPCRs-AS1, where NAS2 is the random number generated by the second Attesting System AS2, CertAIK-AS2 is the Attesting Identity Key AIK certificate of the second Attesting System AS2, and ParmPCRs-AS1 is the parameter list of Platform Configuration Register values PCRs requested by the second Attesting System AS2 from the first Attesting System AS1, which may be a list of Platform Configuration Registers PCR determined in the first Attesting System AS1 or a list of components determined in the first Attesting System AS1.
2) The first Attesting System AS1 transports the random number to its own Trusted Platform Module TPM, extracts corresponding Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 from the TPM based on the parameter list of Platform Configuration Register values PCRs, performed a signature [NAS2, PCRsAS1]Sig on the PCRsAS1 and the NAS2 using a private key of an Attesting Identity Key AIK of the AS1, extracts the measurement logs LogAS1 corresponding to the PCRsAS1 from the Store Measurement Log SML of the first Attesting System AS1, and transmits a second message to the second Attesting System AS2, wherein the second message includes a random number generated by the AS1, the Attesting Identity Key AIK certificate of the AS1 and a parameter list of Platform Configuration Register values PCRs requested by the AS1 from the AS2.
Particularly, upon reception of the message 1, the first Attesting System AS1 firstly transports the random number NAS2 generated by the second Attesting System AS2 to the Trusted Platform Module TPM of the first Attesting System AS1, and then extracts from the Trusted Platform Module TPM of the first Attesting System AS1 the corresponding Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 based on the parameter list ParmPCRs-AS1 of Platform Configuration Register values PCRs requested by the second Attesting System AS2 from the first Attesting System AS1, the signature [NAS2, PCRsAS1]Sig on the extracted Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 and the random number NAS2 generated by the second Attesting System AS2 performed using the private key of the Attesting Identity Key AIK of the first Attesting System AS1, extracts the measurement logs LogAS1 corresponding to the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 from the Store Measurement Log SML of the first Attesting System AS1, and finally transmits the second message (a message 2=PCRsAS1∥LogAS1∥[NAS2, PCRsAS1]Sig∥NAS1∥CertAIK-AS1∥ParmPCRs-AS2) to the second Attesting System AS2, where NAS1 is the random number generated by the first Attesting System AS1, CertAIK-AS1 is an Attesting Identity Key AIK certificate of the first Attesting System AS1, and ParmPCRs-AS2 is the parameter list of Platform Configuration Register values PCRs requested by the first Attesting System AS1 from the second Attesting System AS2, which may be a list of Platform Configuration Registers PCR determined in the second Attesting System AS2 or a list of components determined in the second Attesting System AS2.
3) The second Attesting System verifies the signature against a public key of the Attesting Identity Key AIK certificate, the random number NAS2 generated by the AS2, and the PCRsAS1, discards the second message if the signature is invalid or otherwise transmits the NAS1 to a Trusted Platform Module TPM of the AS2, extracts from the Trusted Platform Module TPM of the second Attesting System AS2 corresponding Platform Configuration Register values PCRsAS2 of the AS2 based on the parameter list ParmPCRs-AS2 of Platform Configuration Register values PCRs requested by the AS1 from the AS2, performs a signature [NAS1, PCRsAS2]Sig on the PCRsAS2 and the NAS1 using a private key of an Attesting Identity Key AIK of the AS2, extracts the measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRsAS2 of the AS2 from the Store Measurement Log SML of the AS2, and transmits to a Trusted Third Party TTP a third message including a authentication random number generated by the second Attesting System AS2.
Particularly, upon reception of the message 2, the second Attesting System AS2 firstly verifies the signature against the public key of the Attesting Identity Key AIK certificate of the first Attesting System AS1, the random number NAS2 generated by the second Attesting System AS2 and the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 in the message 2, discards the message 2 if the signature is invalid or otherwise transports the random number NAS1 generated by the first Attesting System AS1 to the Trusted Platform Module TPM of the second Attesting System AS2, and then extracts from the Trusted Platform Module TPM of the second Attesting System AS2 the corresponding Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 based on the parameter list ParmPCRs-AS2 of Platform Configuration Register values PCRs requested by the first Attesting System AS1 from the second Attesting System AS2, performs the signature [NAS1, PCRsAS2]Sig on the extracted Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 and the random number NAS1 generated by the first Attesting System AS1 using the private key of the Attesting Identity Key AIK of the second Attesting System AS2, extracts the measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 from the Store Measurement Log SML of the second Attesting System AS2, and finally transmits the third message (a message 3) to the Trusted Platform Party TTP, where the message 3=NAS2-TTP∥NAS1∥CertAIK-AS1∥CertAIK-AS2∥PCRsAS1∥LogAS1∥PCRsAS2∥LogAS2 and wherein NAS2-TTP is the authentication random number generated by the second Attesting System AS2.
4) The Trusted Platform Party TTP verifies validity of the CertAIK-AS1 and the CertAIK-AS2, generates a verification result ReAIK-AS1 of the CertAIK-AS1 and a verification result ReAIK-AS2 of the CertAIK-AS2, verifies correctness of the corresponding measurement logs LogAS1 against the PCRsAS1 and discards the message if it is incorrect or otherwise verifies the correctness of the measurement logs LogAS2 corresponding to the PCRsAS2 against the PCRsAS2 and discards the message if it is incorrect or otherwise evaluates trustworthiness of the first Attesting System AS1 against the measurement logs LogAS1 and reference integrity values of respective components in the LogAS1 and trustworthiness of the first Attesting System AS2 against the measurement logs LogAS2 and reference integrity values of respective components in the LogAS2, generates a platform integrity verification result RePCRs-AS1 and platform remediation information RemAS1 of the first Attesting System AS1 and a platform integrity verification result RePCRs-AS2 and platform remediation information RemAS2 of the second Attesting System AS2, calculates relevant parameters of the first Attesting System AS1 and the second Attesting System AS2 from the private keys and transmits a fourth message including the relevant parameters to the AS2.
Particularly, upon reception of the message 3, the Trusted Platform Party TTP firstly verifies validity of the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System AS1 and the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2, generates the verification result ReAIK-AS1 of the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System AS1 and the verification result ReAIK-AS2 of the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2, verifies correctness of the measurement logs LogAS1 corresponding to the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 in the message 3 against the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 in the message 3 and discards the message if it is incorrect or otherwise verifies correctness of the measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 in the message 3 against the Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 in the message 3 and discards the message if it is incorrect or otherwise evaluates trustworthiness of the first Attesting System AS1 against the measurement logs LogAS1 corresponding to the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 in the message 3 and the reference integrity values of the respective components in the measurement logs LogAS1 and the reference integrity values of the respective components in the measurement logs LogAS1 and evaluates trustworthiness of the second Attesting System AS2 against the measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRsAS2 of the second Attesting System AS2 in the message 3 and the reference integrity values of the respective components in the measurement logs LogAS2, and generates the platform integrity verification result RePCRs-AS1 and the platform remediation information RemAS1 of the first Attesting System AS1 and the platform integrity verification result RePCRs-AS2 and the platform remediation information RemAS2 of the second Attesting System AS2, and next the Trusted Platform Party TTP calculates against the private keys a signature [NAS2-TTP∥CertAIK-AS1∥
ReAIK-AS1∥PCRsAS1∥RePCRs-AS1∥RemAS1∥NAS1∥CertAIK-AS2∥ReAIK-AS2∥PCRsAS2∥RePCRs-AS2∥ RemAS2]Sig on the authentication random number NAS2-TTP generated by the second Attesting System AS2, the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System AS1, the verification result ReAIK-AS1 of the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System AS1, the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1, the platform integrity verification result RePCRs-AS1 of the first Attesting System AS1, the platform remediation information RemAS1 of the first Attesting System AS1, the random number NAS1 generated by the first Attesting System AS1, the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2, the verification result ReAIK-AS2 of the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2, the Platform Configuration Register values PCRsAS2 of the second Attesting System AS2, the platform integrity verification result RePCRs-AS2 of the second Attesting System AS2, and the platform remediation information RemAS2 of the second Attesting System AS2, and finally transmits to the second Attesting System AS2 the message 4=ReAIK-AS1∥RePCRs-AS1∥RemAS1∥ReAIK-AS2∥RePCRs-AS2∥RemAS2∥[NAS2-TTP∥CertAIK-AS1∥ReAIK-AS1∥PCRsAS1∥RePCRs-AS1∥RemAS1∥NAS1∥CertAIK-AS2∥ReAIK-AS2∥PCRsAS2∥RePCRs-AS2∥RemAS2]Sig.
5) The AS2 verifies the signature against the fourth message and discards the message if the signature is invalid or otherwise generates a result of the AS1 accessing the AS2 and transmits a fifth message to the first Attesting System AS1.
Particularly, upon reception of the message 4, the second Attesting System AS2 firstly verifies the signature [NAS2-TTP∥CertAIK-AS1∥ReAIK-AS1∥PCRsAS1∥RePCRs-AS1∥ RemAS1∥NAS1∥CertAIK-AS2∥ReAIK-AS2∥PCRsAS2∥RePCRs-AS2∥RemAS2]Sig against a public key of the Trustworthy Platform Party TTP and discards the message if the signature is invalid or otherwise generates the result Reaccess of the first Attesting System AS1 accessing the second Attesting System AS2, based on the verification result ReAIK-AS1 of the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System AS1 and the platform integrity verification result RePCRs-AS1 of the first Attesting System AS1 in the message 4, wherein a value of the result Reaccess is Allowed/Disallowed/Isolated, and then transmits a message 5=NAS2-TTP∥PCRsAS2∥[NAS1∥PCRsAS2]Sig∥Reaccess∥ to the first Attesting System AS1.
6) The AS1 verifies the signature against the fifth message and discards the message if the signature is invalid or otherwise verifies the signature in the fourth message and terminates the protocol process if the signature is invalid or otherwise performs access control against the verification result ReAIK-AS2 of the CertAIK-AS2, the platform integrity verification result RePCRs-AS2 of the second Attesting System AS2 and the result Reaccess of the first Attesting System AS1 accessing the second Attesting System AS2.
Particularly, upon reception of the fifth message (the message 5), the first Attesting System AS1 firstly verifies the signature [NAS1∥PCRsAS2]Sig against the public key of the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2 and discards the message if the signature is invalid or otherwise verifies the signature [NAS2-TTP∥CertAIK-AS1∥ReAIK-AS1∥PCRsAS1∥RePCRs-AS1∥RemAS1∥NAS1∥CertAIK-AS2 ∥ReAIK-AS2∥PCRsAS2∥RePCRs-AS2∥RemAS2]Sig in the message 4 and terminates the protocol process if the signature is invalid or otherwise performs access control against the verification result ReAIK-AS2 of the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System AS2 and the platform integrity verification result RePCRs-AS2 of the second Attesting System AS2 in the message 4 and the result Reaccess of the first Attesting System AS1 accessing the second Attesting System AS2.
In the foregoing trusted platform evaluation protocol based on Tri-element Peer Authentication, the messages exchanged between the first Attesting System AS1 and the second Attesting System AS2 are transported over a secure channel therebetween; the messages exchanged between the second Attesting System AS2 and the Trusted Third Party TTP are transported over a secure channel therebetween; if the first Attesting System AS1 does not wish any knowledge of the second Attesting System AS2 about platform configuration information of the first Attesting System AS1, then the measurement logs LogAS1 corresponding to the Platform Configuration Register values PCRsAS1 of the first Attesting System AS1 and the platform remediation information RemAS1 of the first Attesting System AS1 are transported over a secure channel between the first Attesting System AS1 and the Trusted Third Party TTP; and if the Attesting Identity Keys AIK of the Attesting Systems AS are verified between the first Attesting System AS1 and the second Attesting System AS2 based upon Direct Anonymous Attestation DAA, then neither the message 4 nor the message 5 includes the Attesting Identity Key AIK certificate CertAIK-AS1 and the verification result ReAIK-AS1 of the first Attesting System AS1 and the Attesting Identity Key AIK certificate CertAIK-AS2 and the verification result ReAIK-AS2 of the second Attesting System AS2.

## Claims

1. A trusted platform verification method based on Tri- element Peer Authentication, comprising the steps of:
A) transmitting, by a second Attesting System, a first message to a first Attesting System, wherein the first message comprises a random number NAS2 generated by the second Attesting System, an Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System and a parameter list ParmPCRs-AS1 of Platform Configuration Register values PCRs requested by the second Attesting System from the first Attesting System;
B) transporting, by the first Attesting System, the NAS2 to a Trusted Platform Module TPM of the first Attesting System, and then extracting a corresponding Platform Configuration Register values PCRSAS1 from the Trusted Platform Module TPM based on the parameters list ParmPCRs-AS1 of PCRs performing a signature [NAS2,PCRSAS1]sig on the PCRSAS1 and the NAS2 using a private key of an Attesting Identity Key AIK of the first Attesting System, extracting a measurement logs LogAS1 corresponding to the PCRSAS1 from the a Store Measurement Log SML of the first Attesting System; and transmitting a second message to the second Attesting System AS2, wherein the second message comprises a random number NAS1, generated by the first Attesting System, an Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System and a parameter list ParmPCRs-AS2 of Platform Configuration Register values PCRs requested by the first Attesting System from the second Attesting System;
C) verifying, by the second Attesting System, the signature against a public key of the Attesting Identity Key AIK certificate of the first Attesting System, the NAS2 and the PCRSAS1, and if the signature is invalid, then discarding the second message; otherwise, transmitting the NAS1 to a Trusted Platform Module TPM of the second Attesting System, extracting from the Trusted Platform Module TPM of the second Attesting System corresponding Platform Configuration Register values PCRSAS2 against the ParmPCRs-AS2, performing a signature [NAS1, PCRSAS2]sig on the PCRSAS2 and the NAS1 using a private key of an Attesting Identity Key AIK of the second Attesting System, extracting the a measurement logs LogAS2 corresponding to the Platform Configuration Register values PCRSAS2 from the Store Measurement Log SML of the second Attesting System; and transmitting to a Trusted Third Party TTP a third message comprising an authentication random number NAS2-TTP generated by the second Attesting System;
D) verifying, by the Trusted Third Party TTP, validity of the CertAIK-AS1 and the CertAIK-AS2, generating a verification result ReAIK-AS1 of the CertAIK-AS1 and a verification result ReAIK-AS2 of the CertAIK-AS2, and then verifying correctness of the LogAS1 against the PCRSAS1, and if it is incorrect, then discarding the message; otherwise, verifying correctness of the LogAs2 against the PCRSAS2, and if it is incorrect, then discarding the message; otherwise, evaluating trustworthiness of the first Attesting System against the LogAS2 and reference integrity values of respective components in the LogAS1 and trustworthiness of the second Attesting System against the LogAs2 and reference integrity values of respective components in the LogAs2, generating a platform integrity verification result RePCRs-As1 and platform remediation information RemAS1 of the first Attesting System and a platform integrity verification result RePCRs-AS2 and platform remediation information RemAS2 of the second Attesting System, calculating relevant parameters of the first Attesting System AS1 and the second Attesting System AS2 from the private keys and transmitting a fourth message comprising the relevant parameters to the AS2;
E) verifying, by the second Attesting System, the signature against the fourth message, and if the signature is invalid, then discarding the message; otherwise, generating a result of the AS1 accessing the AS2 and transmitting a fifth message to the first Attesting System AS1; and
F) verifying, by the AS1, the signature against the fifth message, and if the signature is invalid, then discarding the message; otherwise, verifying the signature in the fourth message, and if the signature is invalid, then terminating protocol process; otherwise, performing access control against the verification result ReAIK-As2 of the CertAIK-As2, the platform integrity verification result RePCRs-As2 of the second Attesting System AS2 and a result Reaccess of the first Attesting System AS1, accessing the second Attesting System AS2.

2. The trusted platform verification method based on Tri-element Peer Authentication according to claim 1, wherein the list of Platform Configuration Registers PCR in the step A) is a list of Platform Configuration Registers PCR determined in the first Attesting System or a list of components determined in the first Attesting System.

3. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 1, wherein the list of Platform Configuration Registers PCR in the step B) is a list of Platform Configuration Registers PCR determined in the second Attesting System or a list of components determined in the second Attesting System.

4. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 1, wherein the messages exchanged between the first Attesting System and the second Attesting System are transported over a secure channel therebetween.

5. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 1, wherein the messages exchanged between the second Attesting System and the Trusted Third Party are transported over a secure channel there between.

6. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 1, wherein if the second Attesting System cannot know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based on Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message comprises the CertAIK-AS2 and the verification result ReAIK-AS2 of the CertAIK-AS2 and the CertAIK-As2 and the verification result ReAIK-AS2 of the CertAIK - AS2.

7. The trusted platform verification method based on Tri-element Peer Authentication according to claim 1, wherein relevant parameters of the first Attesting System AS1 and the second Attesting System AS2 comprise
a signature on the authentication random number NAS2-TTP generated by the second Attesting System, the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System, the verification result ReAIK-AS1 of the Attesting Identity Key AIK certificate CertAIK-AS1 of the first Attesting System, the Platform Configuration Register values PCRsAS1 of the first Attesting System, the platform integrity verification result RePCRs-AS1 of the first Attesting System, the platform remediation information RemAS1 of the first Attesting System, the random number NAS1 generated by the first Attesting System, the Attesting Identity Key AIK certificate CertAIK-AS2 of the second Attesting System, the verification result ReAIK-AS2 of the Attesting Identity Key AIK certificate CertAIK- AS2 of the second Attesting System, the Platform Configuration Register values PCRsAS2 of the second Attesting System, the platform integrity verification result RePCRs -Ast2 of the second Attesting System and the platform remediation information RemAS2 of the second Attesting System.

8. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 2, wherein if the second Attesting System cannot know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based on Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message comprises the CertAIK-AS1 and the verification result ReAIK-AS2 of the CertAIK-AS1 and the CertAIK-AS2 and the verification result ReAIK-AS2 of the CertAIK-AS2.

9. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 3, wherein if the second Attesting System cannot know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based on Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message comprises the CertAIK-AS1 and the verification result ReAIK-AS1 of the CertAIK-AS2 and the CertAIK-AS2 and the verification result ReAIK-AS2 of the CertAIK-AS2.

10. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 4, wherein if the second Attesting System cannot know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based on Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message comprises the CertAIK-AS1 and the verification result ReAIK-AS1 of the CertAIK-AS1 and the CertAIK-AS2 and the verification result ReAIK-AS2 of the CertAIK-AS2.

11. The trusted platform verification method based upon Tri-element Peer Authentication according to claim 5, wherein if the second Attesting System cannot know platform configuration information of the first Attesting System, then the LogAS1 and the platform remediation information RemAS1 of the first Attesting System are transported over a secure channel between the first Attesting System and the Trusted Third Party; and if the Attesting Identity Keys of the Attesting Systems are verified between the first Attesting System and the second Attesting System based on Direct Anonymous Attestation DAA, then neither the fourth message nor the fifth message comprises the CertAIK-AS1 and the verification result ReAIK-AS1 of the CertAIK-AS1 and the CertAIK-AS2 and the verification result ReAIK-AS2 of the CertAIK-AS2.