Encrypted key with empty password does not work

[RanjeetMishra]

Because of password len check here, encrypted key with empty password does not work.

1. Should encrypted key with empty password be supported?
2. If answer to point 1 is yes, would below check suffice?

func isEncryptedKey(der []byte) bool {
	type EncryptedPrivateKeyInfo struct {
		Algorithm     asn1.RawValue // Encryption algorithm and parameters
		EncryptedData []byte        // The encrypted private key bytes
	}
	var encryptedKey EncryptedPrivateKeyInfo

	_, err := asn1.Unmarshal(der, &encryptedKey)
	return err == nil
}