openssl ecparam -genkey -name prime256v1 -noout -out ec256-key-pair.pem
https://notes.salrahman.com/generate-es256-es384-es512-private-keys/
bashopenssl ecparam -genkey -name prime256v1 -noout -out ec_private.pem openssl ec -in ec_private.pem -pubout -out ec_public.pem