master key is then encrypted with AES-256-CBC with a key derived from the passphrase using SHA-512 and OpenSSL's EVP_BytesToKey and a dynamic number of rounds determined by the speed of the machine which does the initial encryption

Hi my friends .
I want to crack the bitcoin backup wallet.dat file  and access its private key. I went through good steps and I can say that if I can extract the sha-512  from the wallet.dat, you can easily crack all the wallets using the key and the IV that is in the sha-512.
Is it possible to extract sha-512 from a wallet.dat?
As you know, sha-512 is created in each wallet as follows.
sha-512 (nDerivations + salt + passphrase)
Can anyone help me how to extract this  encrypted code sha-512 of bitcoin wallet.dat file
Thank you all