I’m not a cryptographer byt does it use the same encryption (wich i guess it does) than it’s same.

In bitcoin the nsec is a random number and npub is derived from it.(using elyptic curve cryptography )The said number is then hashed multiple times, to add more layers of security.

It’s called asymmetric cryptography meaning easy to verify and veeeeeeeery hard to calculate backwards

“Bitcoiners for developers” on saylor academy explains this in pretty human terms.

Nostr uses same or very similar processes, i guess you can find that info in Nostr git repository in some of first NIPs

In any case i think it’s the same amount of digits so it should be equally hard to brute force 🤷🏼‍♀️