The X9.63 specifications require purchasing, which may make it difficult for implementors looking to implement ECDSA and ECDH.

To make the WebCrypto spec freely accessible and implementable, and potentially meet W3C requirements on normative references, the references should be updated to refer to the SECG specifications. In particular, SEC 1 ( http://www.secg.org/sec1-v2.pdf ) provides normative definitions for ECDSA and ECDH that can be freely implemented.

SEC 2 provides explicit definitions for the secp256r1, secp384r1, and secp521r1 curves referenced in the document, but which lack a normative reference for implementors as to what these mean.