How to create a Certificate Signing Request in 2021 (Windows 11/10)?

Saket Upadhyay
3 min readOct 8, 2021

How to create your own CSR for SSL implementation.

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What is a CSR?

A certificate signing request (CSR) is the initial step to implement SSL/TLS on your server. The CSR is generated in the target server itself and contains important information about your server like — domain, country, owner details and general contact details along with the public key of the organization/individual which is signed by their respective private key.

The Certificate Authority (CA) will use the data from the CSR to build your SSL Certificate.

Key information in a CSR

A general purpose CSR will contain the following information -

Common Name (CN): your domain or a domain wildcard.

Organization (O): Name of your organization.

Organization Unit (OU): Sub-unit/division of above organization which will handle this certificate.

Locality (L): The city where your organization is located. (This shouldn’t be abbreviated.)

State/County/Region (S): The State where your organization is located.

Country (C): The ISO_3166-1 two-letter code for the country where your organization is located. (eg. IN/US/GB/AU/RU/CN)

Email (Email): Your/organization's department's email address.

How to create signing request in Windows?

Using certreq.exe

certreq.exe is a tool in Microsoft Windows which can create a CSR.

To create one, you will need to follow 3 simple steps.

Step 1: Setup base information in *.ini file

In this step, you need to fill your information in a specific format (like one given below) which will be used by certreq.exe to create your CSR.

You can use the file below as a template. Be sure to change the contents of Subject according to your use case. Key values in “Subject” field are your CN, OU, O, et cetera. as discussed in previous section.

You can leave the rest as it is. This template will generate RSA (KeySpec = 1) 2048 (KeyLength = 2048) bits keys

Step 2: Generate the CSR.

After you save the above file, you can run the following command in an admin shell to generate your CSR. (I’ve saved the file as CSRinformation.ini)

certreq.exe -new .\CSRinformation.ini CSRrequest.txt

The generated CSR will be stored in CSRrequest.txt

Example of the command in elevated PowerShell

Step 3: Validating the generated CSR.

The generated CSR’s structure should look similar to the one given below, the contents should/will be different.

Now you can submit this in a CSR checker to validate your request before submitting this in your CPanel.

Screenshot of a valid CSR

More resources:

  • You can also generate a CSR with IIS Manager in Windows, this method is well covered in’s article; here is a link for the same —
  • You can read more about certreq.exe and the parameters of the *.ini file in the official documentation —
  • You can check your CSR’s validity at —