Therein lies the rub: you index security on knowing you're compromised, whereas most compromise is imperceptible to the user. Rotating credentials reduces risk.
How much does rotating credentials reduce risk? Should I rotate once a year? Once a month?
Rotating every day would be even more secure, right? But how much more? I think not very much.
I must accept some risk to communicate. I accept that I can manage my private key and keep it safe. It’s my identity, so it’s important to prevent leaking that credential. I think it’s better to protect the credential than to frequently rotate with all the potential errors there.
The risk is that I don’t know if I’m compromised. But I think that risk is less than the errors involved in rotating keys according to some arbitrary schedule.
That's not up you, it's up to your adversary.
> How much does rotating credentials reduce risk? Should I rotate once a year? Once a month?
As frequently as possible. Signal for example uses ephemeral keys for each message.
> Rotating every day would be even more secure, right? But how much more? I think not very much.
Stop guessing and use empirical evidence to support your reasoning.
> The risk is that I don’t know if I’m compromised. But I think that risk is less than the errors involved in rotating keys according to some arbitrary schedule.
It's arbitrary because you are making a strawman argument to support a foregone conclusion.
There’s a big difference between identity keys and session keys. It makes total sense to use lots of throw away keys (this is how tls works) but making a new identity key for every message is madness.
There is no empirical evidence for how frequently to rotate your identity keys.
A few years ago NIST started recommending never changing passwords unless they are compromised [0]. Identity keys aren’t exactly the same as passwords but I think they are similar.
I don’t think anyone quantifies how much of a benefit there is to changing your password nor how frequently to change it. “As frequently as possible” is not useful advice as that could be every minute or never. I need more actionable guidance so I can weigh it against other priorities
That's not what happens (new identity for each message) and compromise of a Signal identity key has no impact on message security, unlike GPG. Also it's not how all TLS works; it's how TLS works with perfect secrecy ciphers only.
> There is no empirical evidence for how frequently to rotate your identity keys.
Certainly not if you refuse to look for it.
> A few years ago NIST started recommending never changing passwords unless they are compromised
Passwords derive session keys (cookies) which rotate very frequently. You have a lot to learn about computer security, I'm happy to make some reading recommendations if you're sincerely interested.
It makes more sense for user credentials that might have been phished but I'm not sure that converts directly to machine managed keys.