Comment by po1nter | Hacker News Reader

Comment by po1nter | Hacker News Reader

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> - Is it better to use a different passphrase on each key, or does using the same one not matter much?

It is better to use a different passphrase for each key but it is also less convenient unless you're using a password manager (personally, I'm using KeePass)

> - How much less secure is it to not use a passphrase on a key?

That depends on the security of the computer where the keys are. I remember a Firefox vulnerability where one site exploiting it was looking for ssh keys on the local file system. So I'd say that a passphrase is very important.

> - Should you use a different key per user account, per server, or per use-case (i.e. personal or work)?

Personally I'm using a key per account per host.

> - Does increasing the amount of bits in a key really have an effect on the security of the key, or does it not make much difference in a real-world use?

Yes up until 2048 where the returns of increasing the amount of bits will start diminishing.[1]

  [1]: https://www.gnupg.org/faq/gnupg-faq.html#no_default_of_rsa4096

> It is better to use a different passphrase for each key but it is also less convenient unless you're using a password manager (personally, I'm using KeePass)

If you are going to use a password manager to store them there's no point in using different passphrases.

Why not? Granted the passphrase are in one place but as long as your password store doesn't get compromised managing to brute force a key's password then only gives you access to the machine(s) that one key is accepted on.

Also, the keys don't have to reside on the same device the password store is on. If you have one key per client device for example.

Because if your password manager is compromised, so are all of the passphrases stored in it. So what would the point, then, be of using different ones?

So because a password manager is one-stop shopping (something that I'm subconsciously uneasy about, to be sure), it's pointless to use different passphrases, one of the major selling points of password managers.

So to protect against that, don't use a password manager. Which means that you're more likely to re-use passphrases, because lots of them are hard to remember and keep straight. So breaking one gets access to many others.

My head spins.

I was originally going to post something along these lines, but then I realized that this argument doesn't work the same in this particular context, and the parent isn't necessarily arguing against password stores in general. Sure, it might be better (in the sense of not concentrating your risk to a single file) to have a strong (importantly, private) scheme for creating passwords (say, based on the site and account name). But if you're restricted to some inane restrictions ("6-10 alphanumeric characters"), then there's not really a strong argument against a password manager in this case.

Sure, in general, you want to avoid password reuse to isolate password compromises / security breaches (some companies are still storing passwords in plaintext in 2016, ugh). But in this case, we're talking about private keys that should never leave your local machine. If those are compromised (even passphrase-protected), then it's not inconceivable to think that your password store might also be compromised.

> he parent isn't necessarily arguing against password stores in general.

Yeah, reliazed that, my post was just my "logical" progression.

The compromise I use is to break the cycle: Use a password manager to generate strong passwords (and different ones, because breaches happen), and use a hardware token-based password for the manager itself. At least that's the compromise I'm comfortable with.

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