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Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

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Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#141

Post by mcintyre1994 »

jpindar wrote: post #113
oblib wrote: post #66

Earlier quoted context omitted.

No, not really. There are not many of photos of me on the web and any that are were taken from a distance and too low res to id me. I've been stingy about that for a long time. FB doesn't have my phone number and I disabled the email address I used to sign up. I delete all my cookies often and use different browsers and turn off and reset my modem to get a new IP address. I have no apps on my phone, don't use iCloud,…

>don't use the native "Contacts" app, I made my own for that. That's a good idea. You could then grant other apps permission to see your contacts, but have the app optionally return fake or empty data.

I doubt iOS lets a custom contacts app respond to a request from another app for contacts though. It'll presumably respond empty data (since they have no contacts in the native app), but with no option to give it the actual contacts if you wanted to.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#142

Post by andrewstuart2 »

pbhjpbhj wrote: post #137
eternalban wrote: post #119

Earlier quoted context omitted.

Excuse me. The issue is biometrics. "We'll delete the picture" =/= "we'll delete the control points and features extracted from your pics".

Under the EU GDPR (eg https://www.eugdpr.org/ ) it appears that they'll need explicit consent to retain the data (all of it, anything related and traceable to the person) and users will both have a right to view it and to have it deleted.

That only applies to Europe. The question is whether the data is valuable enough to Facebook to spend the time to add `if (europe)` to their code.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#143

Post by samat »

obmelvin wrote: post #136
eternalban wrote: post #128

Earlier quoted context omitted.

What recovery? You're uploading your pic via your account. It is already associated with you.

As I understood it you are making the argument that they will have information about you from uploading this picture even if they delete the actual picture. I'm genuinely asking if it is possible to recover an individual training example from a model which is shown vast amounts of data. I'm only aware of being able to recover stuff like this - https://ars.els-cdn.com/content/image/1-s2.0-S08936080173020... which is h…

It is not about being able to recover, rather about being able to identify your face on other photos.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#144

Post by dguest »

clamprecht wrote: post #47

Last paragraph of the article: "The new authentication scheme is the second in recent weeks that relies on photos. Earlier this month, Facebook asked users to upload nude photos to Facebook Messenger, as part of an effort to prevent revenge porn. Facebook said it would use the nude photos to create a digital fingerprint against which to compare future posts." Wait what? I had to check whether today was April 1st.

Can someone explain if / how this prevents someone from just changing a single pixel and thus circumventing the hash? Are they using some kind of probabilistic hashing? Or are they just relying on the offenders to not be so clever?

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#145

Post by phjesusthatguy3 »

danso wrote: post #123
Splines wrote: post #120

Earlier quoted context omitted.

I disagree: - It sets a precedent for uploading nude photos to FB and for them asking for it. - You need to trust FB to delete the photos when they receive it. Yes, I understand that they probably will, but really, how many systems are those bits going to touch? How many logs are going to have this information? Can you be really sure? A better implementation would be for the FB client to hash the file and for the has…

> - It sets a precedent for uploading nude photos to FB and for them asking for it. Before we reduce this to a slippery slope, what scenario do you envision in which FB could coax its userbase to upload nude photos? I know the OP is about taking a selfie to prove existence. What would FB use as the basis to mandate the general user to send a self-nude? > You need to trust FB to delete the photos when they receive it.…

> Before we reduce this to a slippery slope, what scenario do you envision in which FB could coax its userbase to upload nude photos?

The one where FB asks its userbase to upload nude photos[0].

[0]https://news.ycombinator.com/item?id=15651710

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#146

Post by eternalban »

obmelvin wrote: post #136
eternalban wrote: post #128

Earlier quoted context omitted.

What recovery? You're uploading your pic via your account. It is already associated with you.

As I understood it you are making the argument that they will have information about you from uploading this picture even if they delete the actual picture. I'm genuinely asking if it is possible to recover an individual training example from a model which is shown vast amounts of data. I'm only aware of being able to recover stuff like this - https://ars.els-cdn.com/content/image/1-s2.0-S08936080173020... which is h…

I understood your question. What I am pointing out is that when you submit an artifact to FB, it is a trivial matter for them to store as 'extended-attributes' your facial biometrics. This has nothing to do with the ML pipeline that munches on data in the aggregate.

As to whether it is possible to extract such information, per my understanding the internals of ML pipelines are rather opaque, so it would be non-trivial, if not impossible. I have no idea either way.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#147

Post by dabockster »

contingencies wrote: post #126
cbhl wrote: post #97

Sure, Facebook might delete your photo when they're done, but they probably won't delete any machine learning models that they trained using it.

... and the new iphone also wants to "set up FaceID", and Samsung's S8+ literally says "Face Recognition: Register your face." / "Fingerprint Scanner: Add your fingerprints." / "Iris Scanner: Register your irises".

FaceID is unique in the sense that it's supposed to be on-device only in the form of an ASIC coprocessor.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#148

Post by dwaltrip »

colordrops wrote: post #72
jsonne wrote: post #51

Earlier quoted context omitted.

I couldn't believe it. This is the most absurd thing I have ever heard.

It really does seem like something an elite private club would do to get a laugh out of fooling the proles while smoking a cigar and browsing the pictures.

It's more like oblivious high-paid product managers and devs who can't fathom why people wouldn't trust Facebook or that Facebook might not be a purely beneficial organization.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#149

Post by YeGoblynQueenne »

>> “Please upload a photo of yourself that clearly shows your face. We’ll check it and then permanently delete it from our servers.”

>> To determine if the account is authentic, Facebook looks at whether the photo is unique.

I assume this means that the photo itself is deleted but a one-way hash of it created to test against later.

However, if I change one pixel of a picture of my face, A, to produce a new picture of my face, A', the hash of A' will not be the same as the hash of A, correct? And I can repeat this process n x m times, where n, m the dimension of the image, ja?

Additionally- when they say "unique", do they mean "known as unique" to Facebook, or "unique in the entire world"? If I take a picture of myself and put it on, dunno, my blog on Blogger, what's stopping someone copying it and uploading it to Facebook to pretend it's me? Will Facebook search the entire web for images potentially matching an uploaded image?

For the record, I don't use Facebook. And there are no pictures of myself anywhere on the internets. As if.

Re: Facebook’s New Captcha Test: 'Upload a Clear Photo of Your Face'

#150

Post by contingencies »

dabockster wrote: post #147
contingencies wrote: post #126

Earlier quoted context omitted.

... and the new iphone also wants to "set up FaceID", and Samsung's S8+ literally says "Face Recognition: Register your face." / "Fingerprint Scanner: Add your fingerprints." / "Iris Scanner: Register your irises".

FaceID is unique in the sense that it's supposed to be on-device only in the form of an ASIC coprocessor.

You can't tell with closed source. Anyway, what about "iCloud backup"?
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