generating RSA public key from private key

• https://docs.openssl.org/3.2/man1/openssl-format-options/#format-options
• https://knowledge.digicert.com/general-information/openssl-quick-reference-guide
• https://developers.yubico.com/PIV/Guides/Generating_keys_using_OpenSSL.html

generating private key

openssl genrsa -out private.key 8192

this command will generate private key with length

let's extract public key from newly generated private key

openssl rsa -pubout -in ./private.key -outform PEM -out public.key

# or, whatever

openssl rsa -outform PEM -in ./private.key -pubout -out public.pem