Certificate Signing Request

Definition of Certificate Signing Request

A Certificate Signing Request (CSR) is a digital file that contains encoded information about an entity’s public key and its identity. It is created by an applicant and sent to a Certificate Authority (CA) as part of the process for obtaining an SSL/TLS digital certificate. The CA verifies the information, signs the request digitally, and issues the certificate for use in securing online communications.


The phonetic pronunciation of “Certificate Signing Request” is:sər-TIF-i-kit SY-ning ri-KWEST

Key Takeaways

  1. A Certificate Signing Request (CSR) is a text file containing encoded data about your organization and the domain name you wish to secure.
  2. CSRs are used by Certificate Authorities (CAs) to validate your identity and generate a digital certificate for your domain, which ensures secure communication between your website and its visitors.
  3. Generating a CSR requires the use of cryptographic tools and includes details such as the Common Name, organization name, country, and public key. The private key, which should remain secret, is stored securely on the server it was created on.

Importance of Certificate Signing Request

A Certificate Signing Request (CSR) is essential in the world of technology for its critical role in establishing a secure communication channel between users and online services.

It serves as a formal request submitted by organizations or individuals to a Certificate Authority (CA) to obtain a Secure Socket Layer (SSL) or Transport Layer Security (TLS) certificate, necessary for secure digital interactions.

The CSR contains identifiable data, including the public key, domain name, and other information to verify the requester’s identity.

The CA then validates the request and issues a digital certificate, promoting trustworthiness while enhancing the overall security, privacy, and data integrity for online transactions and communications.


A Certificate Signing Request (CSR) plays a significant role in the process of acquiring a Secure Sockets Layer (SSL) certificate, a digital certificate that establishes a secure and encrypted connection between a web server and a web browser. The primary purpose of a CSR is to provide a detailed set of information about an organization’s server, including its public key, which is required by a Certificate Authority (CA) – an entity that issues SSL certificates.

By generating a CSR, an organization is essentially initiating the process of obtaining an SSL certificate, which is crucial for ensuring online data security, building user trust, and adhering to regulatory requirements. The CSR acts as a formal request, demonstrating an organization’s intent to enable a trusted and secure connection for their website or application.

This document plays a vital role in a CA’s verification process, where the information provided within the CSR is thoroughly vetted and validated. Upon successful verification, the CA will issue an SSL certificate, which can then be installed on the requesting server.

By utilizing an SSL certificate, the organization guarantees encrypted communication and secure transactions for users engaging with their online platforms, bolstering their reputation in the digital space while safeguarding sensitive information.

Examples of Certificate Signing Request

A Certificate Signing Request (CSR) is a block of encoded text containing information about a company or individual that requests a Certificate Authority (CA) to issue an SSL/TLS certificate. This technology is essential for securely transmitting data over the internet. Here are three real-world examples of CSR use:

E-commerce Website: An owner of an e-commerce website needs an SSL certificate to protect sensitive information, such as customer login credentials and payment details. The website owner generates a CSR containing details like the domain name, the company’s legal name, and its physical location. They submit this CSR to a Certificate Authority (CA) like Let’s Encrypt, DigiCert, or GlobalSign. After verifying the provided information, the CA issues an SSL certificate, enabling secure communication between the website and its users.

Company Email Server: A company has set up an email server for its employees and wants to secure the email communication between the server and clients. To do that, the system administrator generates a CSR with the server’s information and sends it to a CA for signing. Once they have obtained the signed SSL certificate, email communication can be encrypted, ensuring the privacy and security of the company’s internal communications.

IoT Devices: Businesses and individuals using Internet of Things (IoT) devices need to secure communications between these devices and their servers. To achieve this, a company generates a CSR and obtains an SSL certificate for each IoT device from a CA. Once the SSL certificates are installed, data transmitted between IoT devices and their servers will be encrypted, preventing potential interception or unauthorized access.

Certificate Signing Request FAQ

What is a Certificate Signing Request (CSR)?

A Certificate Signing Request (CSR) is a file containing your public key and other pertinent information used by a Certificate Authority (CA) to generate an SSL/TLS certificate for your organization. The data in the CSR includes your domain, location, and organization details, and enables the CA to verify your site’s authenticity.

How do I create a Certificate Signing Request?

To create a CSR, you would usually use a tool that comes with your server software or a dedicated utility. Common tools include openssl, IIS, and Keytool for Java-based servers. The process varies depending on the tool; be sure to refer to the documentation for your specific server or software for step-by-step instructions.

What information is required for a CSR?

A CSR typically requires the following information:

  • Common Name (CN): The fully-qualified domain name (FQDN) of your website (e.g.,
  • Organization (O): Your organization’s legally registered name.
  • Organizational Unit (OU): The department or unit within your organization responsible for handling SSL/TLS certificates.
  • City or Locality (L): The city or town where your organization is located.
  • State or Province (ST): The state or province where your organization is located.
  • Country (C): The ISO code for the country where your organization is located. (e.g., US, UK, AU)

How do I submit a CSR to receive an SSL/TLS Certificate?

Once you have generated a CSR, you need to submit it to a Certificate Authority (CA) to receive an SSL/TLS certificate. This process might vary depending on the CA you choose, but generally, you’ll be asked to provide the information found in the CSR, such as the domain name, organization details, etc. Once the CA verifies the information, it will issue the certificate, allowing you to install it on your server.

How can I check if my Certificate Signing Request is valid?

Several online tools and utilities can help you validate your CSR. These tools typically require you to paste your CSR file’s contents into a form, and they will then validate the content and display the information contained within. You can also use the tool you used to create the CSR to verify its details.

Related Technology Terms

  • Public Key Infrastructure (PKI)
  • Secure Sockets Layer (SSL)
  • Transport Layer Security (TLS)
  • Digital Signature Algorithm (DSA)
  • X.509 Certificate Standard

Sources for More Information


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