you can put the SPL logic into a custom splunk command, which can be written in python or C++: https://docs.splunk.com/Documentation/Splunk/8.0.1/Search/Writeasearchcommand
It can work, but frankly, with some effort it should be possible to understand what the custom command does and/or reverse engineer it.
if you speak about the "user", do you mean an internal user in your organisation, who shouldn't see the SPL query, or an external customer, who paid for your reports/dashboards?
