https://bitcoin.stackexchange.com/a/32546 (it's on first page of search result) should answer your question, it has explanation on youtube with example code on C# and Python language.
P.S. I assume you're talking about ECDSA since you're asking the question in Bitcoin forum
Topic: Calculate Z value from r and s (Read 164 times)
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.
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.
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
thank you in advance
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