Copyright (C) 2006 International Business Machines Corporation
Written by Anthony Bussani based on the Trusted Computing Group Software Stack Specification Version 1.2

\\$1

.. ..

..

1 TCG Software Stack Developer's Reference

Tspi_TPM_DAA_JoinCreateDaaPubKey - computes the credential request for the DAA Issuer

 #include <tss/tss_typedef.h>  #include <tss/tss_structs.h>  #include <tss/tspi.h>  "TSS_RESULT Tspi_TPM_DAA_JoinCreateDaaPubKey("  " TSS_HDAA " hDAA ","  " TSS_HTPM " hTPM ","  " UINT32 " authenticationChallengeLength ","  " BYTE* " authenticationChallenge ","  " UINT32 " nonceIssuerLength ","  " BYTE* " nonceIssuer ","  " UINT32 " attributesPlatformLength ","  " BYTE** " attributesPlatform ","  " TSS_DAA_JOIN_SESSION* " joinSession ","  " TSS_DAA_CREDENTIAL_REQUEST* " credentialRequest  ");" 

\Tspi_TPM_DAA_JoinCreateDaaPubKey is the second (between Tspi_TPM_DAA_JoinInit() and Tspi_TPM_DAA_JoinStoreCredential()) out of 3 functions to execute in order to receive a DAA Credential. It computes the credential request for the DAA Issuer, which also includes the Platforms's DAA public key and the attributes that were chosen by the Platform, and which are not visible to the DAA Issuer. The Platform can commit to the attribute values it has chosen.

The hDAA parameter is used to specify the handle of the DAA object. The hTPM parameter is the handle to the TPM object. The authenticationChallengeLength parameter is length of authenticationChallenge (256 bytes - DAA_SIZE_NE1). The authenticationChallenge parameter is the second nonce of the DAA Issuer that is encrypted by the endorsement public key. It is used as a challenge to authenticate the underlying TPM. The nonceIssuerLength parameter is the length of nonceIssuer (20 bytes). The nonceIssuer parameter is the nonce of the DAA Issuer. The attributesPlatformLength parameter is length of attributesPlatform array, which is determined by the DAA Issuer public key (). The length of a single attribute is ln/8. ln is defined as the size of the RSA modulus (2048). The attributesPlatform parameter is an array of attributes to be encoded into the DAA Credential not visible to the DAA Issuer. The joinSession parameter is a structure containing the DAA Join session information. The credentialRequest parameter is the credential request of the Platform, it contains the blinded DAA public key of the platform on which the DAA Issuer will issue the credential the blinded attributes chosen by the Platform.

Tspi_TPM_DAA_JoinCreateDaaPubKey returns TSS_SUCCESS on success, otherwise one of the following values is returned:

TSS_E_INVALID_HANDLE Either the DAA is not valid.

TSS_E_BAD_PARAMETER

TSS_E_INTERNAL_ERROR An internal SW error has been detected.

Tspi_TPM_DAA_JoinCreateDaaPubKey conforms to the Trusted Computing Group Software Specification version 1.2

Tspi_TPM_DAA_JoinInit(3) Tspi_TPM_DAA_JoinStoreCredential(3)