How do we prevent issuance of credentials to other people

[tlodderstedt]

Assumption: Users can be attackers
Use case: someone requests issuance of a COVID certificate and proves her identity with an identity credential. this user can than pass the token to someone else, who requests the actual issuance to her key material

Options:

1. Issuance requires verifiable identity credential as well
2. Device/hardware binding between the different process steps
3. Credential itself is bound to a certain identity/identity credential (i.e. the verifier would ensure the holder binding)

[bellebaum]

2. would probably not be enough, as such a user would likely also be willing to request issuance to someone else's key material himself. By cooperating with the other person, proofs of posession of key material should also not prevent this