return nil, errMalformedJWKECKey
		}

		var curve elliptic.Curve
		switch key.Crv {
		case "P-224":
			curve = elliptic.P224()
		case "P-256":
			curve = elliptic.P256()
		case "P-384":
			curve = elliptic.P384()
		case "P-521":
			curve = elliptic.P521()
		default:
			return nil, fmt.Errorf("Unknown curve type: %s", key.Crv)
		}

		xbuf, err := base64.RawURLEncoding.DecodeString(key.X)
		if err != nil {

		return SigningMethodES3256
	})

	// ES384
	SigningMethodES3384 = &jwt.SigningMethodECDSA{Name: "ES3384", Hash: crypto.SHA3_384, KeySize: 48, CurveBits: 384}
	jwt.RegisterSigningMethod(SigningMethodES3384.Alg(), func() jwt.SigningMethod {
		return SigningMethodES3384
	})

	// ES512

func jsonFloat(f float64) string {
	var tmp [32]byte
	dst := tmp[:0]

	// Convert as if by ES6 number to string conversion.
	// This matches most other JSON generators.
	// See golang.org/issue/6384 and golang.org/issue/14135.
	// Like fmt %g, but the exponent cutoffs are different
	// and exponents themselves are not padded to two digits.
	abs := math.Abs(f)
	fmt := byte('f')
	if abs != 0 {