How to implement these curve for ecdh?

[LuThaiHoc]

Thanks for the project, I succeed verify with additional curve, I tried to using additional curve for key exchange ecdh, how to do it? I following ecdh interface, implement its function but not work:

type Curve interface {
	// GenerateKey generates a random PrivateKey.
	//
	// Most applications should use [crypto/rand.Reader] as rand. Note that the
	// returned key does not depend deterministically on the bytes read from rand,
	// and may change between calls and/or between versions.
	GenerateKey(rand io.Reader) (*PrivateKey, error)

	// NewPrivateKey checks that key is valid and returns a PrivateKey.
	//
	// For NIST curves, this follows SEC 1, Version 2.0, Section 2.3.6, which
	// amounts to decoding the bytes as a fixed length big endian integer and
	// checking that the result is lower than the order of the curve. The zero
	// private key is also rejected, as the encoding of the corresponding public
	// key would be irregular.
	//
	// For X25519, this only checks the scalar length.
	NewPrivateKey(key []byte) (*PrivateKey, error)

	// NewPublicKey checks that key is valid and returns a PublicKey.
	//
	// For NIST curves, this decodes an uncompressed point according to SEC 1,
	// Version 2.0, Section 2.3.4. Compressed encodings and the point at
	// infinity are rejected.
	//
	// For X25519, this only checks the u-coordinate length. Adversarially
	// selected public keys can cause ECDH to return an error.
	NewPublicKey(key []byte) (*PublicKey, error)

	// ecdh performs an ECDH exchange and returns the shared secret. It's exposed
	// as the PrivateKey.ECDH method.
	//
	// The private method also allow us to expand the ECDH interface with more
	// methods in the future without breaking backwards compatibility.
	ecdh(local *PrivateKey, remote *PublicKey) ([]byte, error)

	// privateKeyToPublicKey converts a PrivateKey to a PublicKey. It's exposed
	// as the PrivateKey.PublicKey method.
	//
	// This method always succeeds: for X25519, the zero key can't be
	// constructed due to clamping; for NIST curves, it is rejected by
	// NewPrivateKey.
	privateKeyToPublicKey(*PrivateKey) *PublicKey
}