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Apple's NeuralHash Algorithm Has Been Reverse-Engineered

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Apple’s NeuralHash algorithm—the one it’s using for client-side scanning on the iPhone—has been reverse-engineered.

Turns out it was already in iOS 14.3, and someone noticed:

Early tests show that it can tolerate image resizing and compression, but not cropping or rotations.

We also have the first collision: two images that hash to the same value.

The next step is to generate innocuous images that NeuralHash classifies as prohibited content.

This was a bad idea from the start, and Apple never seemed to consider the adversarial context of the system as a whole, and not just the cryptography.

Tags: algorithms, Apple, backdoors, cryptography, hashes, iOS, iPhone, reverse engineering

Posted on August 18, 2021 at 11:51 AM37 Comments

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