86 lines
4.8 KiB
Markdown
86 lines
4.8 KiB
Markdown
|
# Certificate Lifetimes
|
|||
|
|
|
|||
|
|
As part of our ongoing commitment to ensuring users’ security, Google is
|
|||
|
|
reducing the maximum allowed lifetimes of TLS certificates.
|
|||
|
|
|
|||
|
|
## Upcoming Changes
|
|||
|
|
|
|||
|
|
Beginning with Chrome 85, TLS server certificates issued on or after
|
|||
|
|
2020-09-01 00:00:00 UTC will be required to have a validity period of 398 days
|
|||
|
|
or less. This will only apply to TLS server certificates from CAs that are
|
|||
|
|
trusted in a default installation of Google Chrome, commonly known as
|
|||
|
|
"publicly trusted CAs", and will not apply to locally-operated CAs that have
|
|||
|
|
been manually configured.
|
|||
|
|
|
|||
|
|
Certificates that do not comply with this requirement will not work, and may
|
|||
|
|
cause webpages to fail to load or to render incorrectly.
|
|||
|
|
|
|||
|
|
If a certificate that does not comply with this requirement is issued by a CA
|
|||
|
|
trusted in a default installation of Google Chrome, this will be treated as a
|
|||
|
|
failure to comply with the security policies necessary to being a trusted CA,
|
|||
|
|
and may result in the removal of trust of that CA’s certificates.
|
|||
|
|
|
|||
|
|
## Technical Details
|
|||
|
|
|
|||
|
|
* A certificate will be impacted by this restriction if either the notBefore
|
|||
|
|
of the certificate is on or after 2020-09-01 00:00:00 UTC, or if the first
|
|||
|
|
precertificate logged by the CA to a Certificate Transparency Log that is
|
|||
|
|
qualified at time of issuance is on or after this date.
|
|||
|
|
* The validity period of a certificate is defined within RFC 5280, Section
|
|||
|
|
4.1.2.5, as "the period of time from notBefore through notAfter, inclusive."
|
|||
|
|
* 398 days is measured with a day being equal to 86,400 seconds. Any time
|
|||
|
|
greater than this indicates an additional day of validity.
|
|||
|
|
* To avoid the risk of misissuance, such as due to leap seconds or
|
|||
|
|
CA-configured randomization, CAs SHOULD issue such server certificates with
|
|||
|
|
validity periods of 397 days or less.
|
|||
|
|
|
|||
|
|
## Frequently Asked Questions
|
|||
|
|
|
|||
|
|
* Why is Chrome making this change?
|
|||
|
|
* Shortening certificate lifetimes protects users by reducing the impact
|
|||
|
|
of compromised keys, and by speeding up the replacement of insecure
|
|||
|
|
technologies and practices across the web. Key compromises and the
|
|||
|
|
discovery of internet security weaknesses are common events that can lead
|
|||
|
|
to real-world harm, and the web’s users should be better protected against
|
|||
|
|
them.
|
|||
|
|
* Does this apply to locally-operated CAs, such as those used within
|
|||
|
|
enterprises that use enterprise-configured configured CAs?
|
|||
|
|
* No. This only applies to the set of CAs that are trusted by default by
|
|||
|
|
Google Chrome, and not CAs that are operated by an enterprise and that
|
|||
|
|
have no certification paths to CAs that are trusted by default.
|
|||
|
|
* Is there an enterprise policy to disable this enforcement?
|
|||
|
|
* No. These changes are transparent and do not offer an enterprise control
|
|||
|
|
to override, as they only apply to so-called "publicly trusted" CAs.
|
|||
|
|
Enterprises that wish to have certificates with validity periods longer
|
|||
|
|
than 398 days may do so by using a locally-operated CA that does not have
|
|||
|
|
any certification paths up to a publicly trusted CA.
|
|||
|
|
* Does this mean I have to replace my existing certificates?
|
|||
|
|
* No. This requirement only applies to new certificate issuance on or after
|
|||
|
|
2020-09-01 00:00:00 UTC. Existing certificates whose validity period
|
|||
|
|
exceeds 398 days will continue to work, while new certificates must comply
|
|||
|
|
with these new requirements, such as when they are renewed or replaced.
|
|||
|
|
* Will this make certificates more expensive?
|
|||
|
|
* As with past changes to the maximum certificate lifetimes, many CAs have
|
|||
|
|
committed to providing additional certificates, as needed by the shortened
|
|||
|
|
maximum lifetime, at no additional cost.
|
|||
|
|
* What will happen if a certificate is issued that does not meet these
|
|||
|
|
requirements?
|
|||
|
|
* Google Chrome will reject such certificates as having too long a validity
|
|||
|
|
period, consistent with existing validity-period based enforcement.
|
|||
|
|
Additionally, such certificates will be treated as a critical security
|
|||
|
|
failure by the CA, and may result in further action taken on the CA that
|
|||
|
|
may affect how current or future certificates from that CA function.
|
|||
|
|
Chromium-based browsers will have this enforcement enabled by default, and
|
|||
|
|
will need to modify the source to disable this.
|
|||
|
|
* What are other browsers doing?
|
|||
|
|
* Apple previously announced this change for versions of iOS, iPadOS, macOS,
|
|||
|
|
tvOS, and watchOS, as documented at
|
|||
|
|
https://support.apple.com/en-us/HT211025, which will apply to all
|
|||
|
|
applications, and not just those of Safari. This certificate lifetime
|
|||
|
|
requirement is fully interoperable with Apple’s requirements.
|
|||
|
|
|
|||
|
|
Microsoft, Mozilla, Opera, and 360 have previously indicated their support
|
|||
|
|
for these requirements, although have not yet made announcements at the
|
|||
|
|
time of this post (2020-06-22). Other browsers, including those browsers
|
|||
|
|
based on Chromium, may provide additional guidance or clarification.
|