Make sure the OpenSSL package is available, it can be installed using the package manager as demonstrated in Example 9.1, “Installing openssl on Debian/Ubuntu” and Example 9.2, “Installing openssl on Fedora/RHEL/CentOS”.
openssl
Example 9.1. Installing openssl on Debian/Ubuntu
$ sudo apt-get install ssl-cert openssl
Example 9.2. Installing openssl on Fedora/RHEL/CentOS
$ sudo yum install openssl