My understanding is, it's analogous to writing a note to your manager.
That note is a random number written in ink your manager can't actually read; all they can do with that note is sign it. They ask God (used here to represent math itself) how to sign this note, and God gives them a unique signature that also theoretically cannot be used to calculate the number that's written. This signature also proves what you're authorized to do. And then your manager hands the note back to you.
The note's sole function past that point is so you can point to the signature thereon and say "this signature proves I can do this, that, etc."
I mean, invoking God kind of works for describing the idea that “math” sometimes knows a secret and can tell someone how to act on that secret without telling them the secret.
My understanding is, it's analogous to writing a note to your manager.
That note is a random number written in ink your manager can't actually read; all they can do with that note is sign it. They ask God (used here to represent math itself) how to sign this note, and God gives them a unique signature that also theoretically cannot be used to calculate the number that's written. This signature also proves what you're authorized to do. And then your manager hands the note back to you.
The note's sole function past that point is so you can point to the signature thereon and say "this signature proves I can do this, that, etc."