Neural-hash-collider
Security and privacy
adversarial hash collision tool
SHOW HN2021
How HN took it
8 positive, 47 neutral or asking, 1 mixed, 61 critical, out of 117 comments about the project. Thread score -0.38.
Idea: 3 for, 29 againstPrivacy: 1 for, 22 againstExecution: 3 for, 9 againstDesign: 0 for, 1 against
The thread, comment by comment
Each row is a top-level comment and its replies, in HN's order. Select a cell to open that comment on HN.
positive neutral or mixed critical about another commenter or something else the maker
What HN said
What people liked
Commenters praise the work as a demonstration that pressures Apple to change the system.
From 2 comments
Well done! Hopefully all of this progress toward demonstrating how easy it is to manipulate neural hash will get Apple to rollback the update...
SCUSKU on HNGreat work, I hope people keep hacking the system to lower the system's credibility. This idea is just beyond insane, and the plan to have manual check on user's photos on their…
ipiz0618 on HN
Objections
Perceptual hashes are not collision resistant, so a second hash layer will not fix the design.
From 2 comments
I don't see how this is fixable on their end. Several people have suggested simply layering several different perceptual hash systems, with the assumption that it's difficult to…
blintz on HNI've seen a lot of comments "muddying the waters" (intentionally or not) about whether hash colliders like the one demonstrated above can be used to carry out an attack. So I…
saithound on HN
Hash collisions could be used to frame people or flood reviewers with false positives.
From 3 comments
The integrity of this entire system now relies on the security of the CSAM hash database, which has just dramatically increased in value to potential attackers. All it would take…
vermilingua on HNIn addition to the attacks, such as converting legit image to be detected as CSAM (false positive) or circumventing detection of the real CSAM image (false negative), which have…
xucheng on HNSome people seem to be confused why a hash collision of a cat and a dog matters. Here's a potential attack: share (legal) NSFW pictures that are engineered to have a hash…
throwaway384950 on HN
Requests
Apple should roll back or change the NeuralHash scanning update.
From 1 comment
Well done! Hopefully all of this progress toward demonstrating how easy it is to manipulate neural hash will get Apple to rollback the update...
SCUSKU on HN
Questions
Whether a secret second hash function would stop collision attacks.
From 2 comments
I am strongly against Apple’s decision to do on-device CSAM detection, but: wasn’t there a secondary hash whose database is not shared? In theory you need to collide with both to…
jchw on HNI've seen a lot of comments "muddying the waters" (intentionally or not) about whether hash colliders like the one demonstrated above can be used to carry out an attack. So I…
saithound on HN
Alternatives named
Apple's NeuralHash CSAM detection system
From 1 comment
Ongoing related threads: Apple defends anti-child abuse imagery tech after claims of ‘hash collisions’ - https://news.ycombinator.com/item?id=28225706 - Aug 2021 (401 comments)…
dang on HN