Certificates

Automated creation, renewing of certificates is provided by software called certbot. To view a list of the certificates Certbot knows about, run the certificates subcommand: $> certbot certificates
Deleting certificates $> certbot delete --cert-name example.com
Install Certificates Using Apache $> sudo certbot --apache -d example.in -d www.example.in

Checking Passphrase for private key:
openssl rsa -check -in keyfilename
Changing Passphrase:
openssl rsa -des3 -in keyfilename -out newkeyfilename
Installing or trusting certificates: Extensions .crt, .pem and .cer are interchangeable, just change the file name extension, they have the same form. Try this: sudo cp mycert.cer /usr/share/ca-certificates/mycert.pem
sudo dpkg-reconfigure ca-certificates
sudo update-ca-certificates