SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/secplus-csr-purpose

What do you send to a certificate authority to request a certificate?

CSR, which carries your public key and identity details.

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  1. Your private key
  2. A certificate signing request (CSR) ✔
  3. A certificate revocation list

Why: A CSR holds the public key and the name to be certified, and is signed with the matching private key. The private key itself never leaves your system.

Huh, didn't know that: RFC 2986 defines the CSR format as PKCS #10 and says the request is signed by the entity requesting certification.

The dad joke
Why did the server sign its own request? It wanted to prove it had the key.
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References

Answer: A certificate signing request (CSR). A CSR holds the public key and the name to be certified, and is signed with the matching private key. The private key itself never leaves your system.

  1. NIST CSRC Glossary: Certificate Signing Request csrc.nist.gov/glossary/term/certificate_signing_request
    The certificate signing request contains the public key as well as other information to be included in the certificate
    Checked 2026-10-10.
  2. RFC 2986, PKCS #10 Certification Request Syntax www.rfc-editor.org/rfc/rfc2986
    A certification request consists of a distinguished name, a public key, and optionally a set of attributes
    Checked 2026-10-10.

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Security & PrivacyWhich key does a recipient use to verify a digital signature?Security & PrivacyWhat is a certificate revocation list (CRL)?Security & PrivacyWhich protocol lets software check the revocation status of a certificate online, more timely than CRLs?

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