Impenetrable security.

Today I made a comment to someone saying that there is no such thing as impenetrable security. Which, while it may or may not be true, is probably the best thing to assume.

I'm just starting on the path to being knowledgeable about information security, and I have no idea how far I'll walk down that path, but immediately after saying this it occurred to me that an alien species with significantly more advanced technology could have effectively impenetrable security simply because we have no understanding of their technology.

Which, by the way, throws the whole plot of Independence Day into question. Anyway, moving on...

But I think an interesting thought experiment can lend some insight into this. Here's how it goes:

Imagine that you have to crack a well-secured modern computer system and find a specific file on it. The twist? You are not from the modern era. Would it be possible, using the knowledge and technology available at the time, to get at that file if you were from the Renaissance? From the height of the Roman Empire? From ancient Egypt?

Pick an place and time more than 100 years in the past.

The further back in time, and the less advanced the culture, the more awesome your success is.

The better the file is protected, the more awesome your success is.

Success must be plausible given the knowledge of the time. Your job is to explain how it's plausible.

Irreversible encryption algorithms are cheating. Even a modern person wouldn't be able to get at the file. Rot 13 is still easy, though.

And no, persons from the modern era are available for you to ask or force into doing it for you.

On the other hand, no actual time limit is imposed. Spending a decade or two reverse engineering the computer until you understand it better is fine.

Waiting around until technology catches up is cheating, and does not constitute a success.

Now, if anyone reads and responds to this, some interesting stuff might happen. Past experience places the chances low, however.