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Comment by gruez | Hacker News Reader

>but mere rotation strikes me as similar to password rotation ... which is currently discouraged.

Cargo culting strikes again. Forcing password rotation is bad because it causes people to choose passwords with a given pattern (eg. password1, password2, etc.), which defeats any security benefit. Rotating certificates have no such issue, because the key is (presumably) randomly generated.

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Also you can reuse the same key.

Don't you have to go out of your way to do that? You can probably choose a weak RSA key as well (ie. one that's 4096 bits but not a prime), but if you have to go out of your way to do that there's little anyone can do to stop you.

No you don't have to go out of your way to reuse the same key

IIRC the default in most/all ACME clients is to reuse the private key and just get a renewed certificate for it.

Caddy doesn't reuse the private key by default. The user has to explicitly configure it in that broken way.

Does it terminate existing connections and re-handshake when renewing the cert then? Or does it potentially hold many keys in memory for existing sessions? IIRC a TLS session can potentially last for a long time and 0-RTT depends on it being the same key, right? Couldn't find any answers in the docs: https://caddyserver.com/docs/caddyfile/directives/tls#reuse_...

The renewal of the key does not affect existing connections/sessions because they (the sessions) don't use the key directly. The private key is only used in the beginning to agree on the symmetric key, then the symmetric key is used from there onwards.

You can also set your password to "password" but hopefully you don't. Guidelines and technical measures can't keep everybody safe all the time, if they are determined to be unsafe, but that is never an argument against them.

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