Install SSL Certificates in Apache HTTPD on CentOS 6.5 Server
By Shay Anderson on February 2014
The following steps will assist in installing SSL certificates in Apache configuration on a CentOS Web server (CentOS 6.5 in this example).

Install Certificate Files
First, install your certificate files. I place them in these directories: /etc/httpd/conf/ssl.crt/example.com.crt
/etc/httpd/conf/ssl.key/example.com.key
/etc/httpd/conf/ssl.chain/example.com.chain.crt (ignore if not needed)
Change permissions of the certificate key file: # chmod 400 /etc/httpd/conf/ssl.key/example.com.key

Apache Configuration
Next, configure Apache for certificate files: # cp /etc/httpd/conf.d/ssl.conf /etc/httpd/conf.d/ssl.conf.BAK
# nano /etc/httpd/conf.d/ssl.confEdit the file to use your certificate, key and chain certificate (if needed): …
SSLCertificateFile /etc/httpd/conf/ssl.crt/example.com.crt
…
SSLCertificateKeyFile /etc/httpd/conf/ssl.key/example.com.key
…
SSLCertificateChainFile /etc/httpd/conf/ssl.chain/example.com.chain.crt
…
Ensure the Apache configuration file syntax is correct: # apachectl -t
Syntax OKRestart Apache gracefully: # service httpd graceful

credit:http://www.shayanderson.com/linux/install-ssl-certificates-in-apache-httpd-on-centos-6-5-server.htm