[therobot24]

>The only way to avoid this requires an active activity, at which case you've just duplicated the password [e.g. the act of typing is identical to the act of sufficient action to make it virtually impossible to duplicate] which has better known security characteristics.

Only way is active activity? Or just the only way you can think of?

>A single breach and you cannot rely on biometric data for life is the reason this is only safe to use as a "username" and not a password. You won't be able to significantly change your biometrics w/o breaking other identification issues.

You're assuming all recognition algorithms of the same biometric produce the same raw template. That if I get one I can gain access on another.

>Biometrics are only valid as a username or secondary authentication factor

It's often frustrating to discuss things with those who clearly know little about the topic and yet declare their opinion as fact.

[mejari]

>You're assuming all recognition algorithms of the same biometric produce the same raw template. That if I get one I can gain access on another.

Well, is that an unreasonable assumption? With passwords knowing what one person's password used to be or even knowing one hash of their current password tells you nothing about a different hash of their current password. With biometric data points presumably if they get accurate and detailed enough (which you already admit they would have to do to be a valid authentication mechanism) you can extrapolate. Faces are known quantities. Knowing how 999 points of your face are arranged does give you data about how other points on your face are likely to be arranged. We already have modelling software capable of this, so it doesn't seem unreasonable that such methods may be improved if facial recognition gains traction. At the very least it brings down the solution space to a much smaller size the more data points are used, which is the opposite of what happens when more data points (characters) are used in alpha-numeric passwords.

>It's often frustrating to discuss things with those who clearly know little about the topic and yet declare their opinion as fact.

I would agree. Especially opinions like how others "clearly know little about the topic".

But is it as frustrating as someone explaining their reasoning for their statement and then you ignoring that reasoning to discuss their closing statement as the entire argument?

[therobot24]

> Well, is that an unreasonable assumption? With passwords knowing what one person's password used to be or even knowing one hash of their current password tells you nothing about a different hash of their current password.

Yea it is, this is very different from a password, even though it's being used in a similar way. Lets take fingerprints as an example - algorithm A uses minutiae points, and algorithm B does a simple normalized cross correlation between the two images. While this is a toy example, you can see there is a clear difference in what is being stored or even hashed.

> At the very least it brings down the solution space to a much smaller size the more data points are used, which is the opposite of what happens when more data points (characters) are used in alpha-numeric passwords.

No, it doesn't. You'd have better luck using a facebook profile picture printed on an old inkjet than you would trying to use a specific template as the 'solution space' of what other templates may be.

> But is it as frustrating as someone explaining their reasoning for their statement and then you ignoring that reasoning to discuss their closing statement as the entire argument?

I admit that it wasn't the classiest way to respond, and i apologize for it (i'm not going to delete it though, i wrote it and i won't run from it), but the same arguments keep coming up over and over again, and it's very clear that the users making these statements not reading any previous replies so i wasn't going to waste my time going over all the points again and again.

[fweespeech]

> Only way is active activity? Or just the only way you can think of?

https://www.defcon.org/images/defcon-13/dc13-presentations/D...

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10....

> For eliminating type 2 attacks, where a previously intercepted biometric is replayed, Ratha et al. [9] proposed a challenge/response based system. A pseudo-random challenge is presented to the sensor by a secure transaction server. At that time, the sensor acquires the current biometric signal and computes the response corresponding to the challenge (for example, pixel values at locations indicated in the challenge). The acquired signal and the corresponding response are sent to the transaction server where the response is checked against the received signal for consistency. An inconsistency reveals the possibility of the resubmission attack.

Please provide evidence you have a better defense against replay attacks. Then we can go through all the other avenues of attack on biometrics...

> You're assuming all recognition algorithms of the same biometric produce the same raw template. That if I get one I can gain access on another.

The fact replay attacks are taken seriously in regards to biometrics and you arguing you cannot engage in such makes me seriously question your claims of authority on the subject matter.

> It's often frustrating to discuss things with those who clearly know little about the topic and yet declare their opinion as fact.

How many papers basically agreeing some kind of challenge is needed in addition to the biometric will you need before you change your mind?

[therobot24]

> https://www.defcon.org/images/defcon-13/dc13-presentations/D....

Slide 44 has a long list of things other than active movement on the user end. Video liveness tests are effective, but there are more methods available than just activity, contrast to your previous statement.

> http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10..... > Please provide evidence you have a better defense against replay attacks. Then we can go through all the other avenues of attack on biometrics...

When did i discredit replay attacks? It seems like you're setting up a straw man. You said the "only way to avoid this requires an active activity, at which case you've just duplicated the password". I refuted saying there's more than one, and you actually found a source that confirms that.

> The fact replay attacks are taken seriously in regards to biometrics and you arguing you cannot engage in such makes me seriously question your claims of authority on the subject matter.

I didn't claim you can't. The paper you linked (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10....) applies a relay attack to a known system.

  "we propose a system that can attack a minutia-based fingerprint matcher"

In this case, the attack algorithm is building an optimization to determine a viable template - using some prior information of what type of template is acceptable (how it's stored, the features being used to build it, etc.) In real life, this type of information is not readily available, and at best, an attacker is going to be just guessing.

> makes me seriously question your claims of authority on the subject matter.

I honestly don't care what you think, but questioning my credentials is your right.

> How many papers basically agreeing some kind of challenge is needed in addition to the biometric will you need before you change your mind?

When did i ever state that an additional challenge wasn't needed? You're setting up another straw man instead of actually backing up your claims.

Many of my posts mention biometric key-binding as a good alternative to a pure biometric system. In a large scale operation i would never suggest or imply that a pure biometric is good enough - you should really read the rest of the thread. However, what MS implemented here is probably good for the average user.