After some discussions 2-3 months ago, the consensus was that
EcdsaSecp256k1VerificationKey2019 is the correct JSON-LD term to be used as a public key type in a BTCR DID Document. The correct JSON-LD term for a corresponding signature type is
See here for some more background:
Orie Steele has a PR with a spec for these terms:
I think it would be good if anyone working on BTCR could review that PR and comment on it.
These specs are referenced from the Linked Data Cryptographic Suite Registry:
The JSON-LD terms have been added to the DID context (did-v0.11.jsonld):
Note the DID context also reserves the terms
SchnorrSecp256k1VerificationKey2019, but those don’t have specs yet.