Comment by prepend | Hacker News Reader

Comment by prepend | Hacker News Reader

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I don’t want to let an external entity know about my internal servers. So free isn’t an option.

I disagree about expiring knowledge on long internal certs. I want to avoid any network snooping so I use TLS. I don’t worry much about server impersonation since it’s an internal server. There’s no special knowledge required to generate a cert and put it on a server. So if it expires 10 years from now, and everyone involved is gone, then Id just generate a new cert and let it run for 10 more years.

If my GPG key was compromised, I would generate a new key, and notify everyone who uses my key of my new key. It’s not a huge group and the only way they know my public key is me telling them. Fingers crossed, I’ll never need to regenerate and will die with this key.

Rotating my private key would reduce my risk from an unknown compromise. But not sure by how much. And the changeover to a new key would likely introduce a known risk of having partners change stuff and get confused every n months, rather than run the risk of someone getting my key.

Non-expiring keys is good enough for billion dollar Bitcoin wallets, it’s good enough for my GPG. And I wish my Wiki Server that I have to rotate keys every 11 months.

> Rotating my private key would reduce my risk from an unknown compromise. But not sure by how much.

Therein lies the rub: you index security on knowing you're compromised, whereas most compromise is imperceptible to the user. Rotating credentials reduces risk.

I think this is not a fruitful reasoning. Never sharing keys reduces the risk too.

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.

> Never sharing keys reduces the risk too.

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.

> Signal for example uses ephemeral keys for each message.

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

[0] https://pages.nist.gov/sp800-63-3.html

> 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.

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.

I'm not a part of this conversation, but I'd love to see those recommendations if you're willing to share.

What are the odds an attacker can get keys once but isn't able to steal them again after they're rotated?

It makes more sense for user credentials that might have been phished but I'm not sure that converts directly to machine managed keys.

How is free not an option?

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