Self signed certificates using OpenSSL


The openssl toolkit is used to generate an RSA Private Key and a CSR (Certificate Signing Request). It can also be used to generate self-signed certificates which can be used for testing purposes or internal usage.

Step 1: Generate a Private Key
The first step is to create your RSA Private Key. This key is a 1024 bit RSA key which is encrypted using Triple-DES and stored in a PEM format so that it is readable as ASCII text.

openssl genrsa -des3 -out josephamrithraj.key 1024

Step 2: Generate a CSR (Certificate Signing Request)

Once the private key is generated a Certificate Signing Request can be generated. The CSR is then used in one of two ways. 1. The CSR will be sent to a Certificate Authority, such as Thawte or Verisign who will verify the identity of the requestor and issue a signed certificate. 2. To self-sign the CSR.
During the generation of the CSR, you will be prompted for several pieces of information. These are the X.509 attributes of the certificate. One of the prompts will be for “Common Name (e.g., http://www.josephamrithraj.info)”. It is important that this field be filled in with the fully qualified domain name of the server to be protected by SSL. If the website to be protected will be https://www.josephamrithraj.info, then enter http://www.josephamrithraj.info at this prompt. If you want to create a so called “wildcard” certificate, which means the same certificate can be used on an unlimited number of subdomains, just enter an asterisk as the hostname, in our example that would be *.info. The command to generate the CSR is as follows:

openssl req -new -key josephamrithraj.key -out josephamrithraj.csr

Step 3: Remove Passphrase from Key

One unfortunate side-effect of the pass-phrased private key is that Apache will ask for the pass-phrase each time the web server is started. Obviously this is not necessarily convenient as someone will not always be around to type in the pass-phrase, such as after a reboot or crash. mod_ssl includes the ability to use an external program in place of the built-in pass-phrase dialog, however, this is not necessarily the most secure option either. It is possible to remove the Triple-DES encryption from the key, thereby no longer needing to type in a pass-phrase. If the private key is no longer encrypted, it is critical that this file only be readable by the root user! If your system is ever compromised and a third party obtains your unencrypted private key, the corresponding certificate will need to be revoked. With that being said, use the following command to remove the pass-phrase from the key:
cp josephamrithraj.key josephamrithraj.key.temp
openssl rsa -in josephamrithraj.key.temp -out josephamrithraj.key
The newly created josephamrithraj.key file has no passphrase in it anymore.

-rw-r–r– 1 root root 745 Nov 17 22:19 josephamrithraj.csr
-rw-r–r– 1 root root 891 Nov 17 23:22 josephamrithraj.key
-rw-r–r– 1 root root 963 Nov 17 23:22 josephamrithraj.key.temp

Step 4: Generating a Self-Signed Certificate

At this point you will need to generate a self-signed certificate because you either don’t plan on having your certificate signed by a CA, or you wish to test your new SSL implementation while the CA is signing your certificate. This temporary certificate will generate an error in the client browser to the effect that the signing certificate authority is unknown and not trusted.
To generate a temporary certificate which is good for 365 days, issue the following command:

openssl x509 -req -days 365 -in josephamrithraj.csr -signkey josephamrithraj.key -out josephamrithraj.crt

Step 5: Installing the Private Key and Certificate

I generally create a SSL directory under apache and move these certs there.

cp josephamrithraj.crt /usr/local/apache/SSL/
cp josephamrithraj.key /usr/local/apache/SSL/

Step 6: Configuring SSL Enabled Virtual Hosts

<VirtualHost www.josephamrithraj.info:443> 
SSLEngine on
SSLCertificateFile /usr/local/apache/conf/SSL/josephamrithraj.crt
SSLCertificateKeyFile /usr/local/apache/conf/SSL/josephamrithraj.key
SetEnvIf User-Agent “.*MSIE.*” nokeepalive ssl-unclean-shutdown
</VirtualHost>

If you want to redirect connections to the standard, unencrypted port 80, simply use the following lines:

<VirtualHost www.josephamrithraj.info:80>
RedirectPermanent / https://www.josephamrithraj.info
</VirtualHost>

Step 7: Restart Apache and Test 

/etc/init.d/apache2 restart
or 
usr/local/apache/bin/apachectl stop
usr/local/apache/bin/apachectl start
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