Fixes: issues/320.
Adds support for generating an activation challenge using
CertificationParameters.
Achieves symmetry with challenge-generation in
AttestationParameters, in order to provide a challenge to a
TPM to activate a TPM-certified key.
`attest.Activation` currently supports verifying and
generating a challenge given attestationData, an EK, an AK,
and a signature. In the attestationData, the CreationInfo
field is used to further validate and create the resulting
challenge.
In this change, `attest.Certification` will now support
generating a challenge given attestationData, an EK, a
TPM-certified public key, and a signature, in addition to
an AK used to verify the certification of the provided
public key we are generating an activation challenge for.
258084d04e