Calculate Z value from r and s

[elpanxaaa]

Can anyone explain me any clearly answer or code in python with examples how we can calculate Z value from r and s ?? I search in google and youtube and i not saw any correctly answer i just see scam posts or video in youtube.

thank you in advance

[pooya87]

you should first explain what it is you are trying to do and what you have in mind when you say "Z".

if Z is the 256-bit value used in creation of the signature then you can't compute it from r and s, it is computed from the data that was signed. in which case it depends on what was signed, for example in message signing the normalized UTF-8 decode of the message string + a fixed string added to the start of it then hashed twice with SHA256. for a transaction this is a lot more complicated and is not something i can cover in one comment because it includes transaction serialization and working with scripts and changes based on the script type being spent.