Hello everyone,

I'm doing a research project regarding bitcoins for school and everything is going pretty good except for one thing.

While researching the bitcoin protocol i found this image:



There is one problem i've run into however.

I don't fully understand the Initialization vector field (IV).
How is this value generated? Is it generated by the SHA-256 algorithm? Or in a different way?
I assume this value needs to be fixed and public because otherwise people can't redo the calculation to check their hash.

Thanks in advance.