There really isn't
Ask anyone seriously involved in security - whether computer science related, or in general.
A thought experiment: Think about the most important secrets a country can have - now think how they are still discovered by competing countries, enemies, etc.
As long as there are humans in the loop there is a known weakness.
We know about many famous cases of leaks - like the USSR stealing notes from the manhatten project. But I bet there are thousands of secrets which remain secret. We just don't actually know about them, because, y'know, they're kept secret.
This is EXACTLY what I was talking about. The tech that makes the F-22 an unmitigated terror of the skies is of utmost importance, so it’s still kept secret. The barriers around that information are obnoxious, but effective. What blood type a subsection of your military has is of much less importance. That’s why that data was stolen (See: OPM hack) and our best weapons remain secret.