[jwestbury]

I'll go further: Three months is too long. Secrets which are used to authenticate and identify should be rotated far more regularly, using infrastructure which treats them as effectively ephemeral. The industry has learned to do this -- and built the infrastructure to support it! -- for things like user credentials (see: extensive use of AWS IAM roles, rather than user creds). We should be making a push to treat certificates the same way.

(That said, three months is better than any longer period. The shorter the rotation, the lower the risk -- but, more importantly, the stronger the impetus to build strong automation around the process.)

[wongarsu]

A three month expiration time with automatic renewal after two months (as letsencrypt recommends) is a sweet spot for me. When something breaks this gives you 30 days to figure out that something went wrong and to fix it with zero customer impact. The 30 day grace window is also long enough that let's encrypt will send you two emails (at the 19 day and 9 day thresholds) to make you aware that something might be going wrong.

If we lowered the expiration time to say 3 days, with automatic renewal after 2 days, then any breakage on your side or downtime on let's encrypt's side would quickly escalate into https errors. That in turn would train users that those just happen, and make them ignore the big red scary page even when it's an actual attack. That sounds much worse than the small risk from a 30 day certificate.

[vbezhenar]

> If we lowered the expiration time to say 3 days, with automatic renewal after 2 days, then any breakage on your side or downtime on let's encrypt's side would quickly escalate into https errors. That in turn would train users that those just happen, and make them ignore the big red scary page even when it's an actual attack. That sounds much worse than the small risk from a 30 day certificate.

That's already happened. I'm encountering LE errors on random websites so much that I don't care and automatically click through warnings. This is especially troublesome because my government keeps MITM me and I don't like it.

[JohnFen]

This is my experience as well. I encounter cert errors more now than ever, and I tend to ignore them.

[red-iron-pine]

> The shorter the rotation, the lower the risk

the lower the risk of compromised certs / keys. certainly not a lower risk of issues, or surprises.

hopefully -- emphasis on hope -- this regular action becomes routine and easy enough to that it is a low risk behavior.