Before you can generate your SSL Certificate, the certificate requester must create a Certificate Signing Request (CSR) for a domain name or hostname on your web server. The CSR is a standardized way to send the issuing Certificate Authority (CA) your public key, which is paired with a secret private key on the server, and provides relevant information about the requester.
For CSR generation instructions for a specific server, please refer to our index of CSR Generation guides in our SSL Support knowledgebase.
Standard CSR Fields
Common Name (CN)
This is the Fully Qualified Domain Name (FQDN) of your server (i.e. www.google.com). This must match exactly what you type in your web browser or you may receive a security error.
Organization Name (O)
The legal name of your company/organization (i.e. Google, Inc.). Do not abbreviate your company name and it should include the corporate identifier such as Inc., Corp, or LLC (if applicable). If there is no company associated with the request, you can set this field as "None" or "N/A"
The city that you are located in (i.e. Mountain View)
State or Province Name (ST)
The state or province in which you are located in (i.e. California). This field may not be abbreviated.
The country in which you are located in (i.e. United States or US)
The bit-length of the key pair determines the strength of the key and how easily it can be cracked using brute force methods. 2048-bit key size is the new industry standard and is used to ensure security well into the foreseeable future.
Hashing algorithm are used by issuing Certificate Authorities to actually sign certificates and CRLs (Certificate Revocation List) to generate unique hash values from files. It is highly recommended that your certificate be signed with SHA-2 as this is the strongest signature algorithm adopted by the industry.
As mentioned above, in addition to creating a CSR, the web server will also export another file called a private key. The private key is a unique cryptographic key related to the corresponding CSR and should never be shared with anyone outside your secured server environment.
The private key is mathematically used to decrypt whatever sensitive data that’s transmitted and encrypted with its corresponding public key and vice versa. If the private key is lost or compromised, malicious users could potentially read your encrypted communications and put your organization's reputation at risk, which defeats the entire methodology behind the Public Key Infrastructure (PKI).
If the private key is lost or compromised, we highly recommend creating a new key pair and replacing or reissuing your SSL Certificate.
Most CSRs are created in the Base-64 encoded PEM format and include the "-----BEGIN CERTIFICATE REQUEST-----" and "-----END CERTIFICATE REQUEST-----" lines as the header and footer tags of the CSR. A standard PEM format CSR will look like the following example: