CCA profile should support pkix-base64 trust anchors #10
Description
The CCA profile of Corim specifies that attestation key endorsements are PEM-encoded base64 keys
The CCA profile as currently implemented in cover is coded to accept CryptoKeyTypeChoice::Bytes, and interprets the bytes as UTF-8 for a JSON Web Key (JWK). This does not match the spec.
We should accept CryptoKeyTypeChoice::PkixBase64Key and treat the data as PEM-encoded SubjectPublicKeyInfo data.
If JWK is needed downstream for the verification process, then we need to convert the PEM to JWK. Unfortunately, there doesn't seem to be a push-button solution for this conversion among the Rust crate ecosystem, so a bit of manual work will be required.