Generating a Certificate Signing Request (CSR) using OpenSSL (Apache & mod_ssl, NGINX)
A CSR is a file containing your certificate application information, including your Public Key. Generate your CSR and then copy and paste the CSR file into the web form in the enrollment process:
Generate keys and certificate:
To generate a pair of private key and public Certificate Signing Request (CSR) for a webserver, "server", use the following command :
openssl req -sha256 -nodes -newkey rsa:2048 -keyout myserver.key -out server.csr
This creates a two files. The file myserver.key contains a private key; do not disclose this file to anyone. Carefully protect the private key.
In particular, be sure to backup the private key, as there is no means to recover it should it be lost. The private key is used as input in the command to generate a Certificate Signing Request (CSR).
You will now be asked to enter details to be entered into your CSR. What you are about to enter is what is called a Distinguished Name or a DN. For some fields there will be a default value, If you enter ‘.’, the field will be left blank.
Country Name (2 letter code) [AU]: GB State or Province Name (full name) [Some-State]: Yorks Locality Name (eg, city) []: York Organization Name (eg, company) [Internet Widgits Pty Ltd]: MyCompany Ltd\ Organizational Unit Name (eg, section) []: IT Common Name (eg, YOUR name) []: mysubdomain.mydomain.com Email Address []:
Please enter the following ‘extra’ attributes to be sent with your certificate request
A challenge password []: An optional company name []:
Use the name of the web-server as Common Name (CN). If the domain name (Common Name) is mydomain.com append the domain to the hostname (use the fully qualified domain name).
The fields email address, optional company name and challenge password can be left blank for a webserver certificate.
Your CSR will now have been created. Open the server.csr in a text editor and copy and paste the contents into the online enrollment form when requested.
Alternatively one may issue the following command to generate a CSR:
openssl req -sha256 -nodes -newkey rsa:2048 -nodes -keyout myserver.key -out server.csr -subj "/C=GB/ST=Yorks/L=York/O=MyCompany Ltd./OU=IT/CN=mysubdomain.mydomain.com"
Note: If the “-nodes” is entered the key will not be encrypted with a DES pass phrase.