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You don't need short expirations for that. CRLs/OCSP already provided a mechanism for certificates to be revoked before they expire. However, short expirations
by crazygringo 1y ago
You don't need short expirations for that. CRLs/OCSP already provided a mechanism for certificates to be revoked before they expire.
However, short expirations severely limit the damage an attacker can do if they steal your private key.
And they avoid the situations where an organization simply forgets to renew a cert, because automating something so infrequent is genuinely difficult from an organizational standpoint. Employees leave, calendar reminders go missing, and yeah.
- kxxt 1y agoIt's because CRLs/OCSP sucks so now short expiration is rolling out.
- ozim 1y agoCRL doesn’t suck it is just not easy problem on web scale. But seems like there is feasible solution: https://hacks.mozilla.org/2025/08/crlite-fast-private-and-comprehensive-certificate-revocation-checking-in-firefox/ https://hacks.mozilla.org/2025/08/crlite-fast-private-and-co...
- m-p-3 1y agoCRLs are becoming bulky, and OCSP have some privacy implications (telling the CA which websites you visit), plus most browsers are set to soft fail if there's an outage and the request can't be made instead of a hard fail and making the website inaccessible, reducing the security and usefulness of OCSP. Short-lived certificates fixes these issues from an end-user standpoint.
- ozim 1y agoThere are new solutions for CRL just last month: https://hacks.mozilla.org/2025/08/crlite-fast-private-and-comprehensive-certificate-revocation-checking-in-firefox/ https://hacks.mozilla.org/2025/08/crlite-fast-private-and-co...
- aaomidi 1y agoThis has existed for a while. It doesn’t address another major issue with revocation: user agents that aren’t browsers don’t implement it.
- crazygringo 1y agoYup. If your primary goal was fast, efficient certificate revocation, then having certs that still take 90 days to expire rather than 2 years is not the solution you'd come up with. CRLite updates every 12 hours.
- ozim 1y agoIf you have short validity times for certificates it also means you have shorter CRL.
- crote 1y agoNot by definition. The main issue is mass revocation events: the CRL is still going to initially contain up to 100% of certs currently active, and the number of active certs won't meaningfully change. It'll rapidly shrink over time as certs expire, but you still have to deal with that initial massive set.
- tgsovlerkhgsel 1y agoCRL/OCSP had limited effect in practice. A revoked certificate would, if I remember correctly, continue to be accepted by many if not most browsers (by market share).
- tbrownaw 1y ago> You don't need short expirations for that. CRLs/OCSP already provided a mechanism for certificates to be revoked before they expire. But that's an explicit action that's much simpler to ask questions about.