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its not because a naive implementation of privacy enhanced APT would fail that all implementations would failt at protecting privacy. Concatenating all the pack

its not because a naive implementation of privacy enhanced APT would fail that all implementations would failt at protecting privacy. Concatenating all the packages and a variable length noise string together, should go a long way. It would be more fruitful to discuss the different ways an attacker might deduce what software was installed from a naive implementation: download sizes, download date (i.e. new update available for package P, then a substantial fraction of users who were downloading from the server that day were probably installing P etc... In theory an onion router might substantially improve the situation if the attacker has a hard time identifying which server the user is talking to, and thus making it hard to identify if the user is even installing anything at all... sadly I don't trust TOR as long as I can't exclude a specific attack scenario I have always suspected about TOR but never actually known to be present...

brazzy 8y ago
> its not because a naive implementation of privacy enhanced APT would fail that all implementations would failt at protecting privacy. Concatenating all the packages and a variable length noise string together, should go a long way. Sure, but then you are not talking about "just use HTTPS", you're talking about creating your own protocol and requiring all APT packet sources to speak that protocol, requiring a specialized server software, where currently they can just use whatever HTTP server they want. Switching the whole infrastructure and installed base over to that would be a massive multi-year project, not just a handful code and configuration changes.
- DoctorOetker 8y ago
  Note I use the phrase "naive implementation" and was never talking about nor clamoring for "just use HTTPS". The real discussion is not "blindly use HTTPS, or leave it like it is", for me the real interesting question is: can we design a package distribution system that preserves privacy against nation state level actors? can we virtually force those to attack the ATP servers themselves? could we use oblivious transfer ? could we design a fresh minimalist onion router (as opposed to bloated TOR) for package distribution?
  - marcosdumay 8y ago
    > can we design a package distribution system that preserves privacy against nation state level actors? That's a great question. Also, can we do it on top of the current Debian infrastructure (HTTP and everything)? Or do we need to change anything?
    - brazzy 8y ago
      > Also, can we do it on top of the current Debian infrastructure (HTTP and everything)? I'm pretty sure that is not possible, because the current infrastructure is just plain old HTTP file servers (anything that can sling bits will do) run by whoever fancies being a part of it.
      - marcosdumay 8y ago
        If you create an onion layer like the GP proposes, I don't see any loss from it running over HTTP servers.
    - xorcist 8y ago
      It already exists. It's called tor. But the question here was why https isn't default in apt, not why tor isn't.
      - DoctorOetker 8y ago
        you're replying downstream of my comment containing "for me the real interesting question is:..." where I generalized the question away from the false dichotomy "keep apt as it is, or make https default in apt"
  - brazzy 8y ago
    > The real discussion is not "blindly use HTTPS, or leave it like it is", for me the real interesting question is: can we design a package distribution system that preserves privacy against nation state level actors? That is certainly an intersting theoretical question, but in practice there is also the question of the costs of something that requires you to change and complicate the whole distributed infrastructure vs. the benefits - are there actually real people who need privacy against "nation state level actors" specifically concerning the Linux packages they install?
mr__y 8y ago
> variable length noise Just thinking... could this be achieved by simply adding some extra response headers on the mirror side? That is the response could contain some headers like X-Unnecessary-Header-0: [random-string] X-Unnecessary-Header-1: [other-random-string] ... This could be enough to insert random-length noise without the need to invent any new protocol. Of course this would only be effective for smaller packages as I assume that headers size is limited and as a result this would significantly change the perceived download size only for smaller packages.
- DoctorOetker 8y ago
  that might work, and the larger packages might be sent as a sequence of parts, so that essentially all packages have the same size other things to keep in mind is the dependency graph, some large packages might be rather unique in total filesize downloaded

brazzy 8y ago

> its not because a naive implementation of privacy enhanced APT would fail that all implementations would failt at protecting privacy. Concatenating all the packages and a variable length noise string together, should go a long way. Sure, but then you are not talking about "just use HTTPS", you're talking about creating your own protocol and requiring all APT packet sources to speak that protocol, requiring a specialized server software, where currently they can just use whatever HTTP server they want. Switching the whole infrastructure and installed base over to that would be a massive multi-year project, not just a handful code and configuration changes.

DoctorOetker 8y ago
Note I use the phrase "naive implementation" and was never talking about nor clamoring for "just use HTTPS". The real discussion is not "blindly use HTTPS, or leave it like it is", for me the real interesting question is: can we design a package distribution system that preserves privacy against nation state level actors? can we virtually force those to attack the ATP servers themselves? could we use oblivious transfer ? could we design a fresh minimalist onion router (as opposed to bloated TOR) for package distribution?
- marcosdumay 8y ago
  > can we design a package distribution system that preserves privacy against nation state level actors? That's a great question. Also, can we do it on top of the current Debian infrastructure (HTTP and everything)? Or do we need to change anything?
  - brazzy 8y ago
    > Also, can we do it on top of the current Debian infrastructure (HTTP and everything)? I'm pretty sure that is not possible, because the current infrastructure is just plain old HTTP file servers (anything that can sling bits will do) run by whoever fancies being a part of it.
    - marcosdumay 8y ago
      If you create an onion layer like the GP proposes, I don't see any loss from it running over HTTP servers.
  - xorcist 8y ago
    It already exists. It's called tor. But the question here was why https isn't default in apt, not why tor isn't.
    - DoctorOetker 8y ago
      you're replying downstream of my comment containing "for me the real interesting question is:..." where I generalized the question away from the false dichotomy "keep apt as it is, or make https default in apt"
- brazzy 8y ago
  > The real discussion is not "blindly use HTTPS, or leave it like it is", for me the real interesting question is: can we design a package distribution system that preserves privacy against nation state level actors? That is certainly an intersting theoretical question, but in practice there is also the question of the costs of something that requires you to change and complicate the whole distributed infrastructure vs. the benefits - are there actually real people who need privacy against "nation state level actors" specifically concerning the Linux packages they install?

mr__y 8y ago

> variable length noise Just thinking... could this be achieved by simply adding some extra response headers on the mirror side? That is the response could contain some headers like X-Unnecessary-Header-0: [random-string] X-Unnecessary-Header-1: [other-random-string] ... This could be enough to insert random-length noise without the need to invent any new protocol. Of course this would only be effective for smaller packages as I assume that headers size is limited and as a result this would significantly change the perceived download size only for smaller packages.

DoctorOetker 8y ago
that might work, and the larger packages might be sent as a sequence of parts, so that essentially all packages have the same size other things to keep in mind is the dependency graph, some large packages might be rather unique in total filesize downloaded