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How likely are perceptual hashes to give a false positive? If I take a picture of a tree, how likely is it that a few pixels are going to line up just right in
by vegetablepotpie 5y ago
How likely are perceptual hashes to give a false positive? If I take a picture of a tree, how likely is it that a few pixels are going to line up just right in a hashing algorithm and say it might be child porn? How likely is it that law enforcement is going to understand the limitations of this technology? How likely is it that the judicial system will understand the limitations of this technology before issuing a search warrant?
I can see law enforcement showing up at my door one day demanding to have a look around, and I would have no idea why they’re there, but they’ll want to look through all my personal belongings.
Worse yet, I might come home from work one day, see my windows broken, see my place has been ransacked and my computers are missing. I would call the police to report a burglary only to hear that I’m under investigation and they need me to give them the key to decrypt my hard drives.
I feel like I need to do some risk analysis on my digital life. I need my phone for 2FA apps for investment accounts. If I use a dumb phone, I’m stuck with SMS, which is easy to hack. But if we use iPhones, there is a small but costly risk of a completely erroneous investigation. How do you balance these without knowing the probability and impact of the later?
- markus_zhang 5y agoEDIT: OK I didn't read the article, that's my fault and thanks for the clarification. But the original point stands: I don't want Apple run more scans on my phone. They can scan on Cloud, but not on my phone before it's loaded into Cloud. -------- At least it's a lot more possible to mis classify a photo than a sms message. Plus as I mentioned in another post, what if you have a young kid and you happen to shoot a photo when he or she is not fully dressed?
- hermannj314 5y agoWhy would that photo match a list of hashes of known CSAM though? This technology at Apple is very much about matching hashes.
- markus_zhang 5y agoThanks, original post edited.
- jll29 5y ago> If I take a picture of a tree, how likely is it that a few pixels are going to line up just right in a hashing algorithm and say it might be child porn? p = 1.0. (This is a sports in the machine learning community: https://openai.com/blog/adversarial-example-research/ https://openai.com/blog/adversarial-example-research/ .)
- oxfordmale 5y agoIt is more likely someone malicious will send you a picture of a tree that has been doctored to match the hash of a known offending image. Of course you will be off the hook after a long embarrassing investigation.
- smegger001 5y agoand after your children have been taken away preemptively by CPS possibly for months and given to a foster home that may actually be abusive.