func (es *EccSigner) Verify(buf, sig []byte) ([]byte, error) {
	var err error

	// decode
	dec, err := b64.DecodeString(string(sig))
	if err != nil {
		return nil, err
	}

	// verify
	err = es.VerifyBytes(buf, dec)
	if err != nil {
		return nil, err
	}

	return dec, nil
}
func (es *EccSigner) Verify(buf, sig []byte) ([]byte, error) {
	var err error

	// decode
	dec, err := b64.DecodeString(string(sig))
	if err != nil {
		return nil, err
	}

	// verify
	err = es.VerifyBytes(buf, dec)
	if err != nil {
		return nil, err
	}

	return dec, nil
}
// Verify creates a signature for buf, comparing it against the URL-safe base64
// encoded sig and returning the decoded signature. If the sig is invalid, then
// ErrInvalidSignature will be returned.