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Comment by xedarius | Hacker News Reader

I think this has been mentioned before on HN. Finger prints, retina scans, brain scans are not passwords, they're userid's.

If the scanner could read a password out of my head then it would be a password. But merely knowing it's my brain isn't good enough (for secure transactions at least).

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Yup, you just nailed it. Here is the best writing on just that I've found (and have shared before on HN):

http://blog.dustinkirkland.com/2013/10/fingerprints-are-user...

Biometric data makes for great usernames, but not so much for a password. How do you "reset" your brainwaves? The wishy-washy part of TFA on that made me question the entire premise.

That's not a complete complaint. If the password were your brainwaves, why would you still need to reset it? Did someone else steal your brain and you need to make sure they no longer have access?

> Did someone else steal your brain and you need to make sure they no longer have access?

Password databases get compromised all the time; so would a "brainprint" database. You can change a password.

That's what one-way hash functions are for. You never store the raw fingerprint data, just its unique salted hash so the data cannot be reused elsewhere.

It only takes one case of blatant disregard by a trusted source to spoil the entire process. What do you do when the scandal leaks that X Co didn't do due diligence and now 100 million of their customer's brainprints are leaked and able to be compromised?

That's the same reasoning for text passwords, yet there are huge password dumps every year.

It only takes one place where security standards aren't implemented properly to have your print leaked forever.

Never mind a malicious user managing to alter the code to leak the print before it's hashed.

Or even someone physically accosting you and retrieving a brain scan. They could do the same thing and force you to give up a password, but at least the password you can change later on.

> Or even someone physically accosting you and retrieving a brain scan. They could do the same thing and force you to give up a password, but at least the password you can change later on.

For that matter, a password is always your choice to reveal or not, taking the cost and alternative into account. Biometric information isn't.

Or messing with the RNG so that the salt isn't actually random. That would never happen :)

Security measures are going to have to deal with situations where people are potentially acting under compulsion and need plausible deniability.

No they don't. American credit cards handle it the right way already with minimal technology around security. Make a good-faith attempt to validate, but generally treat the transaction as legitimate. If it was not, help law enforcement investigate, and make the compromised party whole as a cost of doing business. Bonus points if you can extort that last part from your vendor in the contract you have with them.

I don't remember where I heard it but someone said something along the lings of "You shouldn't use something that you leave everywhere and can never change as a secure token"

Given they are measuring a response to a photo, change the photo? This seems much more like challenge-response than other forms of biometric data.

The trinity: Something you know, something you have, something you are.

Reading the article, the 'brainprint' seems to be more similar to a challenge/response password than an identity. The brainprint is the brain response to 500 images. It can therefore be changed and replaced by another response to another set of images. It can be seen as a high security biometric challenge/response password mechanism which can not easily be eavesdropped or faked. The brainprint is something you HAVE (the response) which is different from something you ARE (a fingerprint, a retina, a brain)

> different from something you ARE (a fingerprint, a retina, a brain)

How is "something you ARE" a useful classification? A fingerprint can be easily changed. And retina patterns could (probably already can) be faked too.

what happens when instead of my association of apples to keeping doctors away changes to Isaac Newton and Gravity.

does my identity change?

(assuming one image is an apple)

Right, and password should be voluntarily entered. This system would be able to steal my password, e.g. unlocking my laptop, forcing me to look at some photo

Brainprints are not like retina scans and finger prints. They can't be read without you knowing and can be cancelled, as they are tied to a specific stimulus. If you want to change your brainprint password, just change the image it's coded to.

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