Generate a private key and a certificate

certificate.txt

[1] Generate a private key and a certificate
Ref: https://web.archive.org/web/20120203022122/http://www.silassewell.com/blog/2010/06/03/node-js-https-ssl-server-example/

openssl genrsa -out privatekey.pem 1024 
openssl req -new -key privatekey.pem -out certrequest.csr 
openssl x509 -req -in certrequest.csr -signkey privatekey.pem -out certificate.pem

[2] Convert PEM to DER
Ref: https://www.sslshopper.com/ssl-converter.html

openssl x509 -outform der -in certificate.pem -out certificate.der

[3] View PEM encoded certificate
Ref: https://support.ssl.com/Knowledgebase/Article/View/19/0/der-vs-crt-vs-cer-vs-pem-certificates-and-how-to-convert-them
openssl x509 -in certificate.pem -text -noout

[4] View DER encoded Certificate
openssl x509 -in certificate.der -inform der -text -noout