SSL Certificate Using Let's Encrypt for Ubuntu

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

Server Certification


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

Getting the RSA public and private key from conf file.