No. Most proper cryptographic hash systems (e.g. used for verifying files, rather than data structures) never have collisions.
Try to find a SHA256 collision.
Anywhere, ever, in the history of mankind.
This isn't for lack of looking. A lot of very smart people have looked for them. If you find one, I bet you'll be eligible for a tenured faculty slot at a good university, if not more. A whole world of secure systems would need to be re-engineered.
Hypothetical collisions of course exist, by the pigeonhole principle, just not in the real world.
Apple is claiming to have a visual equivalent to a cryptographic hash -- one which won't change with a single byte, but only if the image is substantially different.
At least their security analysis relies on that.
From their whitepaper: "The threshold is selected to provide an extremely low (1 in 1 trillion) probability of incorrectly flagging a given account"
If your claim is that their hash algorithm isn't cryptographic, their security analysis is incorrect.
It's trivial to cause a neural hash non-match-- either imperceptibly with a little noise, or by adding an overlay on the image.
If you downsample and quantize an image before sha256ing it you get a bit of robustness to accidental false-negatives. While both schemes are trivially bypassable.
Yes, absolutely. It's technically possible to find SHA256 collisions accidentally, but it's so unlikely, that if you found one, it would merit serious investigation. People would not believe your statement that you found them accidentally, and "oh, I guess mlajtos really just found the colliding pair by chance" wouldn't be declared until after a very thorough investigation. In the meantime, major stakeholders (e.g. Bitcoin) would probably move away to another hash function, just in case.
Dwyer calculated 1431168 NeuralHashes and found two collisions. Humanity collectively calculates over 120000000000000000000 SHA-256 hashes every second. Still, we're reasonably sure that this immense brute-force search will not lead to any collisions in any reasonable amount of time.
Try to find a SHA256 collision.
Anywhere, ever, in the history of mankind.
This isn't for lack of looking. A lot of very smart people have looked for them. If you find one, I bet you'll be eligible for a tenured faculty slot at a good university, if not more. A whole world of secure systems would need to be re-engineered.
Hypothetical collisions of course exist, by the pigeonhole principle, just not in the real world.