Simple definition
Request containing a public key and identity information to apply for a certificate.
Technical definition
Request containing a public key and identity information to apply for a certificate. In a professional environment, This mechanism usually integrates with other services to have a public key signed by a certification authority without transmitting the private key.
What is it used for?
have a public key signed by a certification authority without transmitting the private key.
Practical example
IIS generates a CSR which is sent to a certification authority.
Common issues
- expired certificate or name not covered
- incomplete confidence chain
- wrong key, revocation or automation of renewal
Key takeaway: Always adapt the diagnosis to the product version and the architecture actually deployed.