Hacking Why I need keys while extracting data from nsp

[Ryoii]

I'm learning about the things about ns for developing homebrew application. These are some questions confuse me.

1. Where are the nsp files from. Is it has been encrypted?
2. And why I need a prod key while extracting data from nsp with hactool.

As I know, nsp can download from eshop or dump from the gamecard (maybe?). No matter where it comes from, it should be decrypted by every single device.
Does this mean that the encrypted nsp can be decrypted by different devices using different keys? Or do different devices use the same key?

 

[thesjaakspoiler]

Does this mean that the encrypted nsp can be decrypted by different devices using different keys? Or do different devices use the same key?

The key used for decrypting the nsp is not console specific, it's the same for everyone.
The NSP is just like a zip file with a password.
The idea was that even if you would intercept the installation file (nsp), you could not open it because you didn't have the password.
If you take keys from the keys.dat and search them with Google you get several hits with the exact same keys.

When you install the nsp on your Switch, it will get encoded again but this time with your console specific key.
Since the Switch can install games on the SD card, files are easily accessible but without the console specific key you cannot simply put them on another Switch's SD card.

 

[Ryoii]

The key used for decrypting the nsp is not console specific, it's the same for everyone.
The NSP is just like a zip file with a password.
The idea was that even if you would intercept the installation file (nsp), you could not open it because you didn't have the password.
If you take keys from the keys.dat and search them with Google you get several hits with the exact same keys.

When you install the nsp on your Switch, it will get encoded again but this time with your console specific key.
Since the Switch can install games on the SD card, files are easily accessible but without the console specific key you cannot simply put them on another Switch's SD card.

Thank you for your detailed answer, I think I understand it.