CSR
also: Certificate Signing Request
A Certificate Signing Request (CSR) is a file containing cryptographic information submitted to a Certificate Authority to obtain an SSL/TLS certificate for securing communications.
A CSR is generated on a server using tools like openssl and contains the public key along with identifying information such as the domain name, organization, and country. The private key is kept secret on the server, while the CSR is sent to a CA (Certificate Authority) for verification and signing.
The CA validates the CSR data, then returns a signed SSL/TLS certificate that the web server can use to encrypt connections. For example, to create a CSR for example.com, you would run: openssl req -new -key private.key -out request.csr
The resulting certificate proves to clients that your domain is legitimate and enables HTTPS connections. CSRs are essential for obtaining trusted certificates from public CAs like Let's Encrypt, DigiCert, or Comodo.