Certificate Signing Request

What Does Certificate Signing Request Mean?

A certificate signing request (CSR) is basically a message that an applicant, usually a person or organization who owns a website that needs to be secured, sends to a certification authority in order to apply for a specific digital identity certificate.


This is a standard procedure in a public key infrastructure (PKI) which allows website owners to prove to their users that the website they are visiting is authentic.

Techopedia Explains Certificate Signing Request

A CSR is usually generated by the server software which the certificate will be used on. The request contains a block of encrypted text which contains specific information which will be included in the certificate such as the owner or organization name, domain name or common name, country, locality, email address, etc.

The CSR also contains the public key of the website which will be included in the certificate while a private key is produced at the same time the request is created.

Once received, the certification authority will create a SSL certificate from the CSR and it will only work with the private key which was created at the same time with the CSR used.

If the private key is lost, then the SSL certificate will no longer work.


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Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.