[Rats] Some new comments for CHARRA YANG module

["Panwei (William)" <[e-mail]>]

Hi Eric,

In modifying the YANG module, I have some new comments about the module.
1. Do we still need the basic-trust-establishment now? It provides the function of retrieving the certificates of TPM2.0. But I think now the certificates can be get from the rats-support-structure and ietf-keystore.
2. The styles of challenge input for TPM1.2 and TPM2.0 are different.
      +---x tpm20-challenge-response-attestation {TPM20}?
      |  +---w input
      |  |  +---w tpm20-attestation-challenge
      |  |     +---w nonce-value          binary
      |  |     +---w challenge-objects* []
      |  |        +---w pcr-list* [TPM2_Algo]
      |  |        |  +---w TPM2_Algo        identityref
      |  |        |  +---w pcr-index*       tpm:pcr
      |  |        +---w TPM2_Algo?          identityref
      |  |        +---w (key-identifier)?
      |  |        |  +--:(public-key)
      |  |        |  |  +---w pub-key-id?   binary
      |  |        |  +--:(uuid)
      |  |        |     +---w uuid-value?   binary
      |  |        +---w tpm-name*           string
In the TPM2.0 challenge input, the nonce is put aside and the challenge-objects is a list. So you can challenge for different pcr-lists of different TPMs in one challenge input.
      +---x tpm12-challenge-response-attestation {TPM12}?
      |  +---w input
      |  |  +---w tpm1-attestation-challenge
      |  |     +---w pcr-index*              pcr
      |  |     +---w nonce-value             binary
      |  |     +---w TPM12_Algo?             identityref
      |  |     +---w (key-identifier)?
      |  |     |  +--:(public-key)
      |  |     |  |  +---w pub-key-id?       binary
      |  |     |  +--:(TSS_UUID)
      |  |     |     +---w TSS_UUID-value
      |  |     |        +---w ulTimeLow?       uint32
      |  |     |        +---w usTimeMid?       uint16
      |  |     |        +---w usTimeHigh?      uint16
      |  |     |        +---w bClockSeqHigh?   uint8
      |  |     |        +---w bClockSeqLow?    uint8
      |  |     |        +---w rgbNode*         uint8
      |  |     +---w add-version?            boolean
      |  |     +---w tpm-name*               string
In the TPM1.2 challenge input, if you want to challenge for different pcr-indexs of different TPMs, you need to construct multiple challenge inputs with different nonce values.
I think it's better to change the style of TPM1.2 to the same one of TPM2.0.
3. In the log-retrieval part, the input uses tpm-name as the identifier, but the output uses certificate-name. The certificate-name isn't used in the log-result, should we also use tpm-name as the identifier of output?

Regards & Thanks!
Wei Pan