EPID name based (NB) Quotes only leave the platform encrypted with an Intel public key.
Malicious use of NB signatures (as unique IDs) can only occur if Service Providers (SP) collude somehow, for example by lying about their identify or sharing private keys.
License agreement between the SP and the Attestation Service will prohibit collusion, under penalty of the Attestation Service revoking an offending SP by no longer verifying attestations.
NB quotes are treated as unique identifiers; NB Quotes only being meaningful to a single Service Provider is not enough to waive this. Therefore, user opt-in is still required before transmitting them.
License agreement between the SP and the Attestation Service will require the SGX application that communicates with the SP to be responsible for getting the user opt-int under penalty of the Attestation Service revoking an offending SP/application by no longer verifying attestations.
Opt-in needs to be “above and beyond” EULA acceptance.