CRL Certificate: In the field of cryptography, a CRL certificate (abbreviation for certificate revocation list) is a list of digital certificates that have been revoked by issuing a CA before the scheduled date of expiry and hence, it should not be trusted.
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What is a CRL Certificate?
CRL is the abbreviation for Certificate Revocation List. Its definition, as per the National Institute of Standards and Technology (NIST) is as follows: “CRL is a list of revoked public-key certificates created and digitally signed by a Certification Authority (CA)”.
However, the Internet Engineering Task Force’ RFC 5280 profile defines CRL as: “A time-stamped and signed data structure that a certificate authority (CA) or CRL issuer periodically issues to communicate the revocation status of affected digital certificates.”
Why do you need a CRL?
As the name implies, a CRL distinguishes untrusted certificates from trusted ones. Moreover, the certification revocation lists are offered on an hourly, daily or weekly basis as per the needs of the provider.
CRL Implications
When the CA revokes a certificate in a particular website, the visitors of the website are shown a warning before they can access the content. The warning is as follows:
“Your connection is not private” attackers might be trying to steal your information from (website url)…”
If you are a business, then the above message is disconcerting as it can drive away visitors and potential customers from your website.
CRL – Why Does CA Revoke a Certificate on Your Website?
There are many reasons why this can happen:
- The Certificate Authority is compromised
- Either someone has compromised your certificate’s private key
- The Certificate Authority is-issued a certificate and issued a new one to replace it
- A certificate was fraudulently signed with a stolen key
Why is a Certificate Revocation List Important?
Digital certificates are valid for a period of 2 years, but some will have 398 days or less if issued on or after 1st September 2020. However, not all certificates will survive their entire validity – some may be revoked early – and this is when they become a part of the Certificate Revocation List. For a client, this can be a problem if they are not aware of which particular certificate is revoked. Hence to make certificate revocations much easier to track, Certificate Authorities will add them to the Certificate Revocation List.
Information Included on a CRL
A certificate revocation list can include the following information:
- Serial number of the certificate
- Signature algorithm of the certificate
- CN – common name
- Extensions of the certificate
- Date and time of revocation
- CRL issuer’s name
- Date by which the next CRL will generate.
FAQ’s on CRL Certificate
Question 1.
What is a CRL Certificate?
Answer:
In the field of cryptography, a CRL certificate (abbreviation for certificate revocation list) is a list of digital certificates that have been revoked by issuing a CA before the scheduled date of expiry.
Question 2.
Why do you need a CRL?
Answer:
Certificate revocations become much easier to track when Certificate Authorities add them to the Certificate Revocation List.
Question 3.
What are the various kinds of information included on a CRL?
Answer:
A certificate revocation list can include the following information: serial number of the certificate, signature algorithm of the certificate, cn – common name, extensions of the certificate, date and time of revocation, crl issuer’s name, the date by which the next crl will generate.