4 ms·

Like what? What's a practical vulnerability or leak?

deleted 5y ago
[deleted]
fulafel 5y ago
Let's say Eve was working at Google with access to the ciphertext and io traffic, and was a jealous lover to a iPhone user Alice. They could be interested in profiling IM app usage, to know about size profile of content (pictures?) were stored at what times to know about Alice's activity profile when out of sight. They could also be interested in fingerprinting apps used so they could be matched to for example different dating apps. It's not hard to imagine something business or government related in place of this of course. And do this analysis in aggregate and follow many people at once. Apple could and for all we know possibly has implemented countermeasures for many of these cases, eg to make it hard to distinquish users from the mass of ciphertext.
- manigandham 5y ago
  How are you going to figure out a specific user's content size (of a specific app or content type) from a sea of encrypted exabytes? What about this is practical?
  - fulafel 5y ago
    I'm just sketching something, I'm not claiming to have developed a vulnerability research result here from my arm chair. But there's a lot of terrain between "it's encrypted so there are no attack" and "you haven't presented a fully developed attack" especially about a system we don't know much about. Anyway, there are many scenarios that come to mind for knowing their IO sizes. Apps probably have IO fingerprints. Or you could send the set of suspected users differently sized files to probe them. Etc.
    - manigandham 5y ago
      Basic batching or partitioning of data before offloading to storage would defeat this analysis, and that’s assuming you can access and query so much data regularly. I asked for practical examples. I don’t need an in-depth report to see that this doesn’t qualify. Most of this crypto stuff is completely impractical risk, especially compared to some phishing emails.
      - fulafel 5y ago
        In security engineering we have the standard the other way around - the proponents of a design have the burden of responsibility to argue the system is secure beyond reasonable doubt, and address and elucidate any potential cracks in the security design. The subthread was about potential pitfalls even in presence of encryption.

deleted 5y ago

[deleted]

Let's say Eve was working at Google with access to the ciphertext and io traffic, and was a jealous lover to a iPhone user Alice. They could be interested in profiling IM app usage, to know about size profile of content (pictures?) were stored at what times to know about Alice's activity profile when out of sight. They could also be interested in fingerprinting apps used so they could be matched to for example different dating apps. It's not hard to imagine something business or government related in place of this of course. And do this analysis in aggregate and follow many people at once. Apple could and for all we know possibly has implemented countermeasures for many of these cases, eg to make it hard to distinquish users from the mass of ciphertext.

manigandham 5y ago
How are you going to figure out a specific user's content size (of a specific app or content type) from a sea of encrypted exabytes? What about this is practical?
- fulafel 5y ago
  I'm just sketching something, I'm not claiming to have developed a vulnerability research result here from my arm chair. But there's a lot of terrain between "it's encrypted so there are no attack" and "you haven't presented a fully developed attack" especially about a system we don't know much about. Anyway, there are many scenarios that come to mind for knowing their IO sizes. Apps probably have IO fingerprints. Or you could send the set of suspected users differently sized files to probe them. Etc.
  - manigandham 5y ago
    Basic batching or partitioning of data before offloading to storage would defeat this analysis, and that’s assuming you can access and query so much data regularly. I asked for practical examples. I don’t need an in-depth report to see that this doesn’t qualify. Most of this crypto stuff is completely impractical risk, especially compared to some phishing emails.
    - fulafel 5y ago
      In security engineering we have the standard the other way around - the proponents of a design have the burden of responsibility to argue the system is secure beyond reasonable doubt, and address and elucidate any potential cracks in the security design. The subthread was about potential pitfalls even in presence of encryption.