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> Since Apple uses a hashed prefix, Google cannot learn which website the user is trying to visit. Can anyone explain how this works? It isn't making sense to

> Since Apple uses a hashed prefix, Google cannot learn which website the user is trying to visit. Can anyone explain how this works? It isn't making sense to me. If the hash is unique enough to match in a database identifying malicious websites (without false positives), isn't it also unique enough to identify the website the user is trying to visit? At least to anyone with the hashing algorithm? Doesn't it have to be, in order to work at it's intended effect, to match a list of malicious websites?

jaegerpicker 6y ago
It's not about hiding the website you visit but about hiding the ip it was visited from. If Google can't tie your ip to the website request they can't use it to market to you. I'm not sure why the hash is made a big deal but hiding your ip is the real value here.
- lrem 6y ago
  So, you're saying that the URLs visited are not the important bit, just that "someone under this IP is browsing internet" is the most marketable bit?
  - jaegerpicker 6y ago
    No it's the combination of the two. If they tie the ip to the domain and then tie that ip to non-safe browsing websites that were visted by that same ip and they can easily start to identify the "safe" sites you visited. If you stop that IP from being identified (also stopping most if not all browser fingerprinting techniques) than it's MUCH harder to identify you as the person that visited those sites. It's the relationship that really matters. Apples proxy breaks that relationship. So does a good VPN setup.
gsnedders 6y ago
Occasionally, you download a list of hash prefixes. This local database is used to do a probabilistic match as to whether it might be a malicious website. If it might be, you send that hash prefix to Google, who respond with a list of full hashes with that prefix, and then you can go through that list (locally) and determine whether the computed hash is in the malicious set or not (without false positives). The important point is that the full hash is never sent over the wire from the end user: only a prefix (typically four ASCII-encoded hex bytes) is ever transmitted.
- jrochkind1 6y ago
  aha, thanks!
deleted 6y ago
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jaegerpicker 6y ago

It's not about hiding the website you visit but about hiding the ip it was visited from. If Google can't tie your ip to the website request they can't use it to market to you. I'm not sure why the hash is made a big deal but hiding your ip is the real value here.

lrem 6y ago
So, you're saying that the URLs visited are not the important bit, just that "someone under this IP is browsing internet" is the most marketable bit?
- jaegerpicker 6y ago
  No it's the combination of the two. If they tie the ip to the domain and then tie that ip to non-safe browsing websites that were visted by that same ip and they can easily start to identify the "safe" sites you visited. If you stop that IP from being identified (also stopping most if not all browser fingerprinting techniques) than it's MUCH harder to identify you as the person that visited those sites. It's the relationship that really matters. Apples proxy breaks that relationship. So does a good VPN setup.

gsnedders 6y ago

Occasionally, you download a list of hash prefixes. This local database is used to do a probabilistic match as to whether it might be a malicious website. If it might be, you send that hash prefix to Google, who respond with a list of full hashes with that prefix, and then you can go through that list (locally) and determine whether the computed hash is in the malicious set or not (without false positives). The important point is that the full hash is never sent over the wire from the end user: only a prefix (typically four ASCII-encoded hex bytes) is ever transmitted.

jrochkind1 6y ago
aha, thanks!

deleted 6y ago

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