Is the Z value generated before the (r, s) values?

Question

I just want to confirm my understanding of signatures for P2PKH transactions.

The signature hash, z, is generated before generating the r and s values of a DER signature, correct?

Answer 1

If by z you mean the hash of the message, then yes, z is required to compute s. Therefore, strictly speaking, you need to compute it before s, but not necessarily before r.

https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm