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Comment by Dylan16807 | Hacker News Reader

It specifically says the dates apply to the end entity. They're not trying to get people off SHA1 in a couple months, they're trying to get them off in a year or two.

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Just to clarify: the other replies are correct. The logic is that if the leaf certificate has an expiry after Dec 31st, 2015 then the whole chain must be SHA-256. If the leaf expires before that, then other certificates in the chain don't matter.

If you have a one year certificate (and I always recommend getting one year certificates so that these issues don't affect you and so that renewal becomes an annual chore, not an irregular panic) then you don't have to worry.

StartSSL simply need to cut new intermediates, signed with SHA-256, and provide them to customers once the leaf certificates that they issue start to stretch into 2016.

Why can't you just verify that the whole chain is SHA-1 instead of using the expiration date as a heuristic?

Because then everything will seem fine until 2017 at which point all the sites break at once. Using the expiration date makes it gradual and shows problems when certificate updates are tested.

Turns out there is already a class 1 SHA-2 intermediate! It's just buried on their site, but you can add it to your chain and it passes SSLLabs validation and otherwise looks totally fine. So this isn't as huge a problem as I had thought.

https://www.startssl.com/certs/class1/sha2/pem/sub.class1.se...

It also says "[...] which include a SHA-1-based signature as part of the certificate chain". In other words, SHA1 is deprecated in the entire chain (minus the root, where the signature is irrelevant).

The root could be SHA1 valid until 2050 and it wouldn't matter. Your bog-standard certificate is valid for one year, and you don't have to care until you're renewing.

> and which include a SHA-1-based signature as part of the certificate chain

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