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CSR (Certificate Signing Request) is an encrypted file which contains the information required by the CA to issue a certificate. It is sent to the Certificate Authority (CA) when an SSL certificate is ordered.

The CSR is generated on the server on which the certificate is to be installed later. All data required by the CA for issuing the certificate must be specified. The CSR is encrypted and signed with the private key that is generated together with the CSR on the server.

The CSR is usually created in a Base-64-based PEM format and can be opened with a simple text editor.

The CSR contains the following information

The public key
Information about key type and length. The most common key size is RSA 2048, but some CAs also support larger key sizes (e.g. RSA 4096+) or ECC keys.
Information about the company and website that you want to secure with SSL, if it was specified when the CSR was generated.

CSR example

Generating private key and CSR with OpenSSL

Enter the following commands to generate the CSR code and private key.

$ openssl req -out server.example.com.csr -new -newkey rsa:2048 -nodes -keyout server.example.com.key

Meaning of the commands

openssl: using the OpenSSL software
req: CSR request command
-new: Create new key
-out server.example.com.csr: Name of the CSR file that is to be output.
-newkey rsa:2048: Encryption with RSA 2048
-nodes -keyout: Output file for the created key
-newkey server.example.com.key: name of the file containing the private key

For further information see https://www.openssl.org/docs/manmaster/man1/req.html

You will then be asked to enter more information.

Country Name (2 letter code) [XX]:DE
State or Province Name (full name) []:Bavaria
Locality Name (eg, city) [Default City]:Examplecity 
Organization Name (eg, company) [Default Company Ltd]:Example GmbH
Common Name (eg, your name or your server's hostname) []:server.example.com
Email Address []:hostmaster@example.com

The input is required for:

Country Name: 2-digit country code, for Germany e.g. DE. Some CAs require capital letters here!
Common Name: Server hostname

These fields can be left blank:

State or Province Name
Locality Name
Organization Name
Email address

You are asked to enter values for additional attributes. This information is not required and the fields can be left blank.

A challenge password []:
An optional company name []:

With this information the files with CSR and Private Key will be created when you press Enter.
To open the files, enter the cat command and the file name. You can then copy the CSR code for certificate ordering.

$ cat server.example.com.csr
$ cat server.example.com.key

Generating the command to create the CSR in SSLManager

Log in to the SSL Manager.

In the Customer Center menu group, click Tools.

The OpenSSL CSR Generator form opens.

Enter the values in the Certificate Details area. Only the Name and Country values are required.

Click Generate.

The OpenSSL command is displayed in the Information pane.

You can copy the command and use it to create a CSR code

CSR - certificate signing request

The CSR contains the following information

CSR example

Generating private key and CSR with OpenSSL

Generating the command to create the CSR in SSLManager