4 ms·

No, it is not. The hash is computed on the client, but hash comparison happens on the server, using some cryptographic magic that only reveals a “visual derivat

No, it is not. The hash is computed on the client, but hash comparison happens on the server, using some cryptographic magic that only reveals a “visual derivative” if enough images match. It’s fairly complex and I don’t recall the details, but the library of “bad” hashes is not accessible.

tsimionescu 5y ago
No, the entire premise of NeuralHash is that no information about your pictures leaves your system unless it has been flagged as 'potentially CSAM'. NeuralHash itself is basically a DB of CSAM hashes encoded as an artificial neural network. In your example, each picture on your phone (that you are trying to upload to iCloud) would be hashed, and the hash would be sent to Apple. This is exactly the opposite of what they are promising with NeuralHash. Edit: I am almost entirely wrong, see the comment reply from krisoft. Apologies!
- krisoft 5y ago
  > In your example, each picture on your phone (that you are trying to upload to iCloud) would be hashed, and the hash would be sent to Apple. This is exactly the opposite of what they are promising with NeuralHash. No. You are wrong. They do hash each image and they do upload the hash derived safety voucher always. Here is the Apple technical paper: https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni... There is a fairly complicated cryptographic algorithm which, according to apple, lets them open the safety voucher only if there is a match with the database. The user devices only have a cryptographicaly blinded version of the hash database which they can’t turn back to real hashes without apple’s private key. This means that the plain neuralhashes are not available to the end users.
  - tsimionescu 5y ago
    Thank you for the actual citation, I edited my comment to avoid misleading others!
    - krisoft 5y ago
      Thank you!

tsimionescu 5y ago

No, the entire premise of NeuralHash is that no information about your pictures leaves your system unless it has been flagged as 'potentially CSAM'. NeuralHash itself is basically a DB of CSAM hashes encoded as an artificial neural network. In your example, each picture on your phone (that you are trying to upload to iCloud) would be hashed, and the hash would be sent to Apple. This is exactly the opposite of what they are promising with NeuralHash. Edit: I am almost entirely wrong, see the comment reply from krisoft. Apologies!

krisoft 5y ago
> In your example, each picture on your phone (that you are trying to upload to iCloud) would be hashed, and the hash would be sent to Apple. This is exactly the opposite of what they are promising with NeuralHash. No. You are wrong. They do hash each image and they do upload the hash derived safety voucher always. Here is the Apple technical paper: https://www.apple.com/child-safety/pdf/CSAM_Detection_Technical_Summary.pdf https://www.apple.com/child-safety/pdf/CSAM_Detection_Techni... There is a fairly complicated cryptographic algorithm which, according to apple, lets them open the safety voucher only if there is a match with the database. The user devices only have a cryptographicaly blinded version of the hash database which they can’t turn back to real hashes without apple’s private key. This means that the plain neuralhashes are not available to the end users.
- tsimionescu 5y ago
  Thank you for the actual citation, I edited my comment to avoid misleading others!
  - krisoft 5y ago
    Thank you!