Ask HN: How did the internet discover my subdomain?

Hi, our company does this basically "as-a-service".

The options how to find it are basically limitless. Best source is probably Certificate Transparency project as others suggested. But it does not end there, some other things that we do are things like internet crawl, domain bruteforcing on wildcard dns, dangling vhosts identification, default certs on servers (connect to IP on 443 and get default cert) and many others.

Security by obscurity does not work. You can not rely on "people won't find it". Once it's online, everyone can find it. No matter how you hide it.

That's not what that phrase means. That's not even what the word "obscure" means. Obscurity is trying to not draw attention to something, or keep it hidden (as in "nobody knows that it's there", not "you know that it's there but can't access it"). Encryption doesn't obscure data unless you're stretching the definition of the word beyond its useful purpose.

verb: keep from being seen; conceal.

In what way is what he’s describing not obscurity?

Two points:

1. Encrypted data is not hidden. You still know that there is data, it's just in a form that you can't understand. Just as difficult higher-level math isn't "obscured" from a non-mathematician (who knows that it is math, but can't decode it), encrypted data is not obscured.

2. You could make the argument that the data is actually hidden, but the fact that data is there is not hidden. This is pointless pedantry, though. It is both contrary to the way that everybody uses the word and stretches the meaning of the word to the point that it's not useful. There is a common understanding of what "Security through obscurity" means ( https://en.wikipedia.org/wiki/Security_through_obscurity ) and interpreting it far beyond that is not useful. It simply breaks down communication into annoying semantic arguments. I enjoy semantic arguments, but not tedious, pedantic ones where one person just argues that a word isn't what everybody understands it to mean.

More specifically, it's about WHAT is being obscured. "Security through obscurity" is about trying to be secure by keeping the details or mechanisms of a system secret, not the data itself.