[38leinad]

Sorry for maybe asking a stupid question, but if i understand correctly, the nounce is just a secret as the private key. But the nounce is not needed for the signature check? So, it can be choosen random and then simply forgotten after signature generation? After first quick google search, it looks like there is also the term nounce use here but it is deterministic and just counted up which does not seem to fit with the article: https://developpaper.com/the-nonce-of-ethereum/ Am I missing something?

[saurik]

The nonce used for ECDSA signatures is not the same as the nonce used for Ethereum signature. The term "nonce" is a general term that is used in any number of systems to mean a value which should only be used once, and might apply to any number of layers or protocols in a given system.

There are various techniques people use for them: a careful counter, a precise timestamp, a hash of the rest of the data, or a random number. Often you can choose as the user... as long as you don't use the same value twice; alternatively, your choice of nonce might be verified by your counter-party (as with Ethereum's account nonces).

The consequences of using the same value twice will also differ: your request might be rejected/ignored, you might be penalized or cause an error, it might expose your identity to a system where you were otherwise anonymous, or it might allow someone to calculate your private key. The high-level idea is what matters, not the specifics.