
Fingerprints are Usernames, not Passwords (2013) - vincent_s
http://blog.dustinkirkland.com/2013/10/fingerprints-are-user-names-not.html
======
UncleSam
This article has been discussed in the past (about 2 years ago).
[https://news.ycombinator.com/item?id=6477505](https://news.ycombinator.com/item?id=6477505)

I think that fingerprints are fine for low security things, but I would never
use it as authentication for anything that touches my bank account.

~~~
gpvos
Has become relevant again because of this post:
[https://news.ycombinator.com/item?id=11548414](https://news.ycombinator.com/item?id=11548414)

------
xoa
This article was and remains wrong, and at least in the comments so far most
people appear to be missing the point, which in turn _weakens security_.
Biometrics are neither user names nor passwords, they're a perfectly valid
factor (along with something you know and something you have) with their own
strengths and weaknesses vs various threat models. One of the most absolutely
fundamental mistakes that can be made with security is sacrificing the good at
the alter of the perfect, because overall security is always, 100% of the time
an economic equation, a time/resource expenditure tradeoff between an attacker
and defender for a given value of information. "Security" as a field also
exists almost exclusively for the benefit of and requiring interaction with
_humans_ , which means that the human factor must always be a fundamental
consideration as well. Or more pithily, a "security" system is garbage if its
users can't use it, won't use it, find it too easy to screw up, or even if the
costs it imposes are greater then the benefits provided.

Biometrics, including finger prints, are human friendly, and that instantly
makes them worthy of consideration as part of a system. Touch ID or the like
can enable a person to use an extremely strong password that would otherwise
be completely uneconomic, and the combination of a limited time, extremely
fast biometric shortcut with a very strong core password, particularly if
combined with coercion code use (only possible for now via jailbreak but
something Apple or another manufacturer could and should implement at all
levels), remote lockout (long available everywhere), etc., may be
significantly better then merely a PIN code alone.

Threat models cannot be ignored for a security system, because they _define_
the system. The greatest threat most people face are remote attacks, with the
next greatest being scatter shots of various sorts (in other words, somebody
was looking to steal or attack _a_ device, not _your_ device in particular).
Persistent targeted threats are an entirely different situation and a password
alone is not even necessarily better in a mobile scenario, because in a mobile
scenario you often do not have even a modicum of control over your
environment. A fingerprint might be possible to lift and use as the author
links, but a PIN code or password can be taken, often even more easily, via
shoulder surfing or cameras. In fact in the modern first world environment
bird's eye view (ceiling/pole-mounted etc) surveillance cameras are becoming
ever more ubiquitous and ever higher resolution. Are people going to seriously
suggest nobody use their mobile device anywhere with a surveillance system?
More and more, how will you even know that? Taking advantage of the ever
increasing cost/performance/size/power improvements powered by the smartphone
revolution, retailers are interested in ever more camera use not for thieves
but for metrics, to figure out exactly what shoppers are doing down to
precisely what they're looking at and for how long. The retailers of course
have no interest in your phone info, and in fact an interest in not making
people worried about that sort of thing. But if we're going to consider
someone going to the specific trouble to rapidly spoof biometric identity for
a specific device, then it's necessary to consider that once the cameras exist
at all access for non-intended purposes may be just a hack or national-
security-directive away.

Basically, it's frustrating to still see people pointing to "somebody broke
into this security system!" as if it means anything without thinking about the
time/resource cost and threat model. Biometrics absolutely have a role to play
in general authentication for the general population for the foreseeable
future. There are paths for improvement there just as in other areas, perhaps
culminating in fusion technologies like security authentication implants wired
into our brains someday, but we'll need functional authentication to get us
that far and passwords alone do not cut for most of the population as
currently implemented.

~~~
junker101
I think you may also be misconstruing the point. Saying that fingerprints
aren't passwords is _not_ the same as saying a fingerprint shouldn't be
required to unlock a phone. (as with most web logins, its userid + password.
But shouldn't be one or the other)

The key point though is that security tokens must be changeable/revocable and
and bio-metric data is not-so-much.

~~~
giovannibajo1
Please describe the threat model in which fingerprint is insecure because it
can't be revoked. Without threat model, evaluation of "security" is useless

~~~
tniswong
When you walk around in your daily life, do you write your password down on
everything you touch? Why not?

~~~
dpark
How is this strawman even a little bit relevant to the question posed? You
don't write your password down on everything you touch even though it _is_
revocable.

~~~
jschwartzi
That's the point. You do leave fingerprints on things you touch. Fingerprints
that can be copied.

~~~
dpark
It doesn't answer the question. Passwords can be revoked and you still don't
want to leave them everywhere. Need for revocability has nothing to do with
maintaining the "secret" and everything to do with mitigating the impact of a
compromise.

If a password is leaked, you need to revoke it in order to mitigate the
potential damage. If a fingerprint is leaked, do you need to do the same? No,
because the security of the fingerprint is not tied to its secrecy.
Fingerprints are not secret. They are just hard to reproduce.

Trying to equate fingerprints to passwords or usernames will inevitably result
in absurd comparisons because fingerprints are neither of these things. They
are an entirely different type of entity.

Fun fact: fingerprint access to banking info on your phone constitutes two
factor authentication. Factor one is the fingerprint (something you are).
Factor two is the phone containing the already-authenticated app (something
you have). Arguably this is a more secure way to access your bank than the
typical one factor username+password you would use online.

~~~
vatotemking
What do you mean by "passwords can be revoked"? I only have one fingerprint
and unlike usernames, it cannot be changed. Once an attacker gets hold of my
fingerprint i can no longer use it. (This is an honest question btw).

~~~
dpark
A changed password is revoked. You revoke the old password when you create a
new one. So passwords support revocation whereas fingerprints do not. The
question posed above is whether the inability to revoke (or change) a
fingerprint matters.

------
colinbartlett
Can a mod please add "(2013)" to the title?

------
colinbartlett
Previous discussion:
[https://news.ycombinator.com/item?id=6477505](https://news.ycombinator.com/item?id=6477505)

------
Aloha
fingerprints are UUIDs, not either usernames or password.

~~~
awqrre
if the connection is encrypted, a UUID is much closer to a password then a
fingerprint

------
Amiga64
My problem with all biometric authentication mechanisms are "what do you do
when your fingerprint/eye/face signature is stolen?" Since these are non-
replacable signatures they are vulnerable as they can't be replaced.

------
newman314
Whenever this topic comes up, I always think the following is a useful read.

[https://technet.microsoft.com/en-
us/library/cc512578.aspx](https://technet.microsoft.com/en-
us/library/cc512578.aspx)

------
ShinyCyril
My background is in EE, so forgive me if this is a stupid question. Are there
any cryptographic hash functions which support a closeness metric? Having
written that out, it seems that such a thing would be contradictory, as to be
able to compute their closeness would give information away about their nature
and thus make them possibly reversible.

~~~
JadeNB
I am also no expert, but I am not sure that I agree with MattSteelblade
([https://news.ycombinator.com/item?id=11550845](https://news.ycombinator.com/item?id=11550845)).

There is certainly such a thing as homomorphic encryption
([https://en.wikipedia.org/wiki/Homomorphic_encryption](https://en.wikipedia.org/wiki/Homomorphic_encryption)),
which allows one to perform transformations on encrypted text without being
able to decrypt it. As long as one of the transformations that can be
performed is a measure of closeness (which is certainly the case for fully
homomorphic encryption
([https://en.wikipedia.org/wiki/Homomorphic_encryption#Fully_h...](https://en.wikipedia.org/wiki/Homomorphic_encryption#Fully_homomorphic_encryption)
)), _and as long as you know the ciphertext of the possible numerical
responses_ , then you can read off closeness without being able to decrypt the
hash.

The emphasised bit is a drawback, but it demonstrates the theoretical
possibility; and, although I don't know of an implementation, nor do I see
anything inherently contradictory about a (non-reversible) system designed
intentionally to reveal closeness information.

------
fweespee_ch
I'm glad to see this post getting upvoted because I've had to argue with
people repeatedly on HN who claim its private / a valid authentication factor.

Look folks, maybe as part of some second or third factor it might be
okay...but you still need a password.

~~~
revscat
> I'm glad to see this post getting upvoted because I've had to argue with
> people repeatedly on HN who claim its private / a valid authentication
> factor.

No, you didn't. There is nothing in your history regarding this subject,
except for this post.

~~~
USAnum1
To give them the benefit of the doubt, it's possible they've made a new
account (45 days old isn't too much tenure).

Heck, I've done it, since it's probably not the best to create a digital
repository of all my opinions!

~~~
dave2000
I create a new account on every site I use roughly once a year. I've no
interest in reputation and there's no way to gain from keeping one account
going. I know I'm not alone in doing this.

------
SFJulie
since fingerprints are "measured" they MAY be usernames. Damn errors, and
false positive refusing to let stuff be non ambiguous. And, like everything
that can be measured ... it can be duplicated... without the knowledge of the
owner of the metric. Damn analogic world refusing to enter the modern didgital
world. (pun digit = finger in latin)

------
xyzzy4
Fingerprints are more like your SSN. You shouldn't trust anyone to store them
and not share them.

~~~
maxerickson
That's the wrong way around though. It shouldn't be the case that there are
consequences for me if someone else presents my fingerprint or SSN. They
obviously aren't secrets, knowing them shouldn't be treated as authentication.

(I guess if you have a human watch someone use a tamper resistant fingerprint
reader you have accomplished some degree of authentication)

------
alexnewman
something you have, something you know, something about you. Nothing has
changed in 40 years. The key is making them reputabiable. It's hard to get new
fingers.

~~~
JadeNB
> The key is making them reputabiable.

Repeatable? (Not typo-hunting; I'm honestly not sure.)

~~~
giaour
I think the GP meant revocable. ("Repudiable" \-- able to be repudiated -- is
neither a word nor exactly correct in this context.)

~~~
JadeNB
Oh, that makes more sense. Thanks!

------
cfieber
that makes sense since my voice is my passport. [verify me]

------
ryanlol
Is this not completely obvious?

~~~
phasmantistes
It's not, not to much of the general populate. This has been reinforced by
decades of science fiction in which fingerprints or handprints get characters
access to secure resources. It's also been reinforced by Apple's messaging
about the fingerprint reader on recent iPhones: it replaces a pin or password,
and so people think of it as a password as well.

~~~
acbabis
Not saying I disagree, but a layperson paying attention to a sci-fi movie
_could_ figure this one out on their own. How often does the protagonist
circumvent the fingerprint scanner with a) A _piece of tape_ , or b) the hand
of the armed guard who was standing _right next to_ the scanner?

~~~
794CD01
You say that as if "secure until I'm dead" is not good enough for 99.999% of
people.

~~~
acbabis
What makes you think I care about Henchman #752? His boss is the one who has
to suffer the consequences of his stolen fingerprint.

~~~
masterzora
In the case where you're using a fingerprint unlock for your own phone, you
are both Henchman #752 and the boss.

~~~
acbabis
Hmmmm, you make a valid point.

------
dlandis
flagged. redirected to spam site when visiting this site on mobile.

------
SlySherZ
I think he has a point, but do we really have better alternatives?

Soon enough computers will be able to check every possibility for passwords as
big as we can remember them. With good algorithms predicting what is likely to
be a valid password, maybe they already can.

Even though I agree fingerprints aren't a good solution, passwords aren't
either. Any ideas?

Maybe we could have some kind of card that would have big keys stored on it.

EDIT: Fixed missing word

~~~
_ZeD_
Start using phrases as password. Mix languages.

~~~
egypturnash
Typing out a lengthy phrase on a phone keyboard, without being able to see any
visual feedback because the letters are replaced with dots, is an exercise in
frustration.

I do this on a regular basis because I have an entire sentence as my LastPass
passphrase.

~~~
pmontra
I do the same with keepass. I think it's the best we can do now.

~~~
egypturnash
I usually hit the "make visible" button on LastPass' password entry slot, to
be honest. I usually make sure nobody's got a good view of my phone when I do
this.

Usually.

I should never become a spy, my security technique is laughable.

