You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: encrypted.go
    path of file: ./repos/ko/vendor/github.com/secure-systems-lab/go-securesystemslib/encrypted
    
    the code of the file until where you have to start completion: // Package encrypted provides a simple, secure system for encrypting data
// symmetrically with a passphrase.
//
// It uses scrypt derive a key from the passphrase and the NaCl secre
    
func MarshalWithCustomKDFParameters(v interface{}, passphrase []byte, kdfLevel KDFParameterStrength) ([]byte, error) {
	data, err := json.MarshalIndent(v, "", "\t")
	if err != nil {
		return nil, err
	}
	return EncryptWithCustomKDFParameters(data, passphrase, kdfLevel)
}