[WebCrypto] WebKit accepts elliptic curve key whose point is not on the curve

[Yoshiaki Jitsukawa]

It might be an implementation-defined behavior but WebKit doesn't throw when importing an elliptic curve key whose point (x, y) is not on the curve.

For example, on Chrome, a DOM exception is thrown with the following code, while not on Safari:

var jwkKey = {
    kty: "EC",
    use: "enc",
    ext: true,
    crv: "P-384",
    x: "1bHwFrsaPRjYq-zFOyLXK8Ugv3EqbVF075ct7ouTl_pwyhjeBu03JHjKTsyVbNWK",
    y: "1bHwFrsaPRjYq-zFOyLXK8Ugv3EqbVF075ct7ouTl_pwyhjeBu03JHjKTsyVbNWK", // (x, y) is not on the P-384 curve
    // y: "OPQLbvRDpocNk4FRQLUVRBbqiauWcnUn7cAC2uSOH6GpSLoTo6B-4LtHq0ydd-iu", // x and this y is on the curve
};
var extractable = true;

crypto.subtle.importKey("jwk", jwkKey, { name: "ECDH", namedCurve: "P-384" }, extractable, [ ]).then(function(result) {
    publicKey = result;
});

[Radar WebKit Bug Importer]

<rdar://problem/80201774>