You seem to be making up a bunch of scenarios that aren't really relevant (what if someone did this and that with sudo, what if the bytes were stored here). You don't want to understand the actual security model, which is fine, but only on Hacker News can someone say with confidence "actually unphishable public keys that can't be leaked, are not good for security." Again, you might as well be arguing against SSH keys. That won't get topped for a while.
I understood the parent poster to be saying that since his passwords are unique and are not stored anywhere, then if his device were to be compromised, the attacker could only steal a password once it is manually entered, in which case it wouldn't automatically compromise his other passwords.
Conversely, if he were to use a password manager on his device to store passkeys, the attacker could compromise all his passkeys once one of them is used.
Admittedly, it is an unusual use case (I mean, how do you generate and remember unique, sufficiently long and random passwords without storing them anywhere?) but I can see how passkeys could be worse for him if this is really what he does.
I don't think a compromised device, and thus access to local data and potentially your password manager, is such an unusual situation, but at that point it is true you do have bigger things to worry about. A device like a computer is also far more likely to get compromised then a phone.
that all said its fairly easy to remember a 20-30 length unique password if you use a passphrase and only have a couple places that are "that important" such as banking, broker, icloud, email, etc. everything else can go in keychain
> I don't think a compromised device, and thus access to local data and potentially your password manager, is such an unusual situation
Right, but what I meant is that it's unusual to have unique passwords for each service *and* have them memorized/not stored anywhere (well, sufficiently long and unique that if an attacker knows a few of them, it doesn't help him guess the others).
That's not what the vast majority of people do.
> that all said its fairly easy to remember a 20-30 length unique password if you use a passphrase and only have a couple places that are "that important" such as banking, broker, icloud, email, etc. everything else can go in keychain
Many of these services don't allow such long passwords where you can use passphrases. For example, both of the banks I use (in two different countries) only allow a fixed size 6 digit numeric password. Somewhat strict password length requirements are not very unusual.
While funny, the problem with this xkcd, besides the password length problem, is that 1000 guesses per second is way, way, way underestimating how fast you can crack passwords nowadays if the service uses password hashing algorithms that are still commonly used. Billions to hundreds of billions of guesses per second is more in line with the right magnitude, given a couple dozen GPUs which can affordably be rented in some cloud service.
When you need to memorize passwords or passphrases for two to four services, you're already in the same entropy requirement ballpark as having to memorize one bitcoin seed (i.e. 128 to 256 bits, depending on how paranoid you are) and therefore you run into the same dilemma: if you can memorize it long-term, it means you don't have enough entropy, and if you have enough entropy, it means you can't memorize it long-term (easily/reliably).
Which is why all but the most clueless or the most paranoid (or those who can afford to lose it) store their bitcoin seed somewhere more permanent than their brain [1] -- unless, say, you only do it very carefully and only temporarily, e.g. if you need to cross a border with a large amount of BTC and you really don't want to attract attention, no matter how scrutinized you'll be (and even then it's probably much better to store the seed somewhere in some creative and imperceptible way).
[1] Bitcoin brainwallets were a lot more popular many years ago, but nobody recommends them anymore due to their severe problems: https://en.bitcoin.it/wiki/Brainwallet
and thats fine, but some of us do for the sites that are important, and that is better then storing something in a password manager weather it be passkey or password.
> For example, both of the banks I use (in two different countries) only allow a fixed size 6 digit numeric password. Somewhat strict password length requirements are not very unusual.
that is a problem with the banks, mine is happy with my 30+ one and has MFA. Banks that can't even support a decent password are unlikely to support passkey anytime soon
> way underestimating how fast you can crack passwords nowadays if the service uses password hashing algorithms that are still commonly used
if the provider (bank) is compromised and salted passwords leaked it doesn't matter, they have already compromised the bank and your account. And i still do not think you can quickly crack a password such as "This15aVERY!!securepasswordEH?!!?"? i could be wrong here
> if you can memorize it long-term, it means you don't have enough entropy, and if you have enough entropy, it means you can't memorize it long-term
not talking about bitcoin seeds here, just accounts.
like i'm not arguing against passkeys just that they have the inherent flaw of existing on a device/somewhere vs something that doesn't.
I agree with your post. I'd just like to add a couple of comments:
> if the provider (bank) is compromised and salted passwords leaked it doesn't matter, they have already compromised the bank and your account.
It matters if the only thing that was leaked/compromised was the hashed password database, but not much else.
In fact, the ones who leak the hashed passwords may not be the same as those who hack your accounts, just look at all the leaks tracked by https://haveibeenpwned.com and consider that anyone could download those hashed passwords and crack them.
> And i still do not think you can quickly crack a password such as "This15aVERY!!securepasswordEH?!!?"? i could be wrong here
You could be right, but I wouldn't be surprised if you were wrong here...
Decades ago, the "John The Ripper" cracker was already very good at cracking these kinds of passwords (when CPUs were single core and much, much slower, and it wasn't even possible to run software on a GPU).
John the Ripper was already capable of using many extremely extensive word lists (in different languages) to quickly run through many such passwords, and simply mutating the password by using l33t speak and adding a few numbers, symbols or using mixed case are extremely popular password strengthening techniques which the software was still capable of cracking very quickly, since that doesn't add much entropy.
Although at the time it probably couldn't crack such a "long" password, I'm sure this type of software has become better and the hardware has definitely become many orders of magnitude faster and more parallel, so I wouldn't be surprised if the example you mentioned is well within "can crack quickly and relatively cheaply" territory, even when using salt, as long as the service is using a traditional password hashing algorithm (and not one of the newer compute-hard or memory-hard KDFs).
I mean, to have an idea of the magnitude of the problem, the brainwallet cracking stories of a decade ago were already pretty mindblowing (even considering that it's a "no salt" scenario).
I don't remember the exact details, but I think there were cases of people using an airgapped computer to compute the SHA-256 hash of some obscure passage of some obscure book or poem in some obscure language and the bitcoins were stolen within seconds of being transferred to these wallets (although, yes, due to the "no salt" problem, it stands to reason that all of these wallets were pre-computed by the attacker).
But still, personally I'd feel a lot more comfortable just using and storing a completely random password with a perfectly known amount of entropy, just to be safe, and deal with the compromised device problem in some other way (such as having a dedicated password management device, like a hardware wallet, if you're really that paranoid).
you were the one that compared it to ssh keys and again: you do not secure root accounts with an ssh keys. Or are you arguing that you should just drop public ssh keys into /root and enable root login?
so how are passkeys are different then ssh keys? there is a private and public key, and if someone gets your private key they get access to everything it unlocks.
they can be sync'd between devices (ie from a secure to compromised), exported, etc exactly like a private ssh key
also i'm not here arguing against passkeys - just pointing out that a long, unique password used in 1 place, that is also not saved anywhere digitally and only exists in my head is going to be more secure then passkeys due to the nature of how they work.
