RFC 5480 §2.1.1 uses this one OID for ECDSA and ECDH keys on every named curve. The algorithm parameters hold the curve OID — for example prime256v1 — which is why a P-256 key's SPKI begins with two OIDs (RFC 7093 §3 shows the bytes).
1.2.840.10045.2.1
id-ecPublicKey
id-ecPublicKey marks an elliptic-curve public key in SubjectPublicKeyInfo; the curve is a separate OID.
1.2.840.10045.2.1 identifies id-ecPublicKey, a public key type. DER: 06072a8648ce3d0201.
- Dotted notation
1.2.840.10045.2.1- DER encoding
06072a8648ce3d0201- Category
- a public key type
- Also known as
ecPublicKey, EC public key- OpenSSL short name
id-ecPublicKey- Parent
- 1.2.840.10045 ansi-X9-62
- Listed by
- the ecdsa.com catalog