https://stackoverflow.com/questions/8290435/convert-pem-traditional-private-key-to-pkcs8-private-key

https://gist.github.com/destan/b708d11bd4f403506d6d5bb5fe6a82c5

https://www.namecheap.com/support/knowledgebase/article.aspx/9834/69/how-can-i-find-the-private-key-for-my-ssl-certificate

https://askubuntu.com/questions/773676/how-to-get-back-lost-root-ca-certificates-gnome-2-key-storage-after-accide

https://support.ssl.com/Knowledgebase/Article/View/19/0/der-vs-crt-vs-cer-vs-pem-certificates-and-how-to-convert-them