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This is a difficult argument to counter; for instance, are you sure that signal can't decrypt your messages? If so, do you remain sure knowing that they can upd

This is a difficult argument to counter; for instance, are you sure that signal can't decrypt your messages? If so, do you remain sure knowing that they can update the app? As a security person I really can't think of any service (or piece of hardware) which I think satisfies the threat model where the provider is both clever and truly hostile.

tptacek 7y ago
Yes, you're pretty sure about Signal, because it's end-to-end encrypted; you can verify what the binary you're running is actually doing (you have to have the expertise to do so, but then, even if Signal was written entirely in browser Javascript, you'd still need the cryptography expertise to verify it). By design, Signal doesn't depend on its serverside deployment for cryptographic security. That's not true of G Suite.
- stubish 7y ago
  You can verify what the binary did while you were watching. You can't verify what it did before, or what it will do next. OP said hostile and clever, and part of clever is only being hostile when nobody is watching. Apps that don't snoop constantly, delay transmissions, and hide transmissions in existing and expected communication channels are much harder to catch.
  - tptacek 7y ago
    No, I'm saying, you can crack open the binary and see what it's capable of doing. If Signal wanted, it could obfuscate itself in various ways to make that hard, but (1) you'd notice that pretty quickly (that the code was hinky) and (2) Signal does not in fact want to do that. You personally might not be able to do that (but then, you personally might not be able to spot a defective authenticated key exchange either), but people can. Once someone spots the "Signal Backdoor", that's it for Signal. There's a lot of incentive to do that legwork. In contrast, G Suite could be comprehensively backdoored, and you'd have no way of knowing, no matter what your level of systems programming competence. I'm not saying they are backdoored; I rather doubt that they are, and I myself trust G Suite more than most other applications I use. But the point is, the trust you have to have in G Suite is different and more demanding than the trust you have to have in Signal.
    - stubish 7y ago
      This assumes that everyone gets the same binary, and the binary doesn't get updated. There is no reason that the binary delivered to your phone by the Google Play Store needs to be the same as the binary delivered to a reporter's phone. Even if we can trust the binary (and I agree, with Signal as the example we probably can), the application distribution mechanism and the underlying OS and its update mechanisms are still a problem.
      - kaoD 7y ago
        There are still mechanisms to mitigate reliance on trust. If you truly cared you wouldn't download it from Play Store and you wouldn't use a stock Android ROM. Of course that moves the problem up to the firmware level but the attack space is getting narrower. With G Suite you rely on trust from the ground up.
      - pvg 7y ago
        There is no reason that the binary delivered to your phone by the Google Play Store needs to be the same as the binary delivered to a reporter's phone. That's moving the goalposts to individual targeting, though. The individual targeting scenario is not that interesting because, as the winged quote from the technical literature goes, "YOU’RE STILL GONNA BE MOSSAD’ED UPON".
Wowfunhappy 7y ago
> As a security person I really can't think of any service (or piece of hardware) which I think satisfies the threat model where the provider is both clever and truly hostile. ...I can. Disconnect from the internet. It's a pain, and it won't be useful advice in many cases, but if you're a newsroom doing sensitive investigations on powerful individuals? I could make a case for it. Although, you'd want to ditch G Suite. (You can certainly think up clever attacks that work without internet, but disconnecting really does remove most vectors.)
dwighttk 7y ago
It may be that we never can say "Google employees aren't randomly snooping on your files." We shouldn't start saying it for things that prove nearby but entirely different things just because we won't ever be able to say it definitively.
millstone 7y ago
The threat model does not need to be that the provider as a whole is truly hostile. It could be "a rogue employee went snooping" or "the server got hacked" or "there was an access control bug." Instead of "trust us to keep your data", what if Google said "we don't have your data." That would give me more confidence, since it both makes the hostile actor's job much harder and it's also easier to verify.

tptacek 7y ago

Yes, you're pretty sure about Signal, because it's end-to-end encrypted; you can verify what the binary you're running is actually doing (you have to have the expertise to do so, but then, even if Signal was written entirely in browser Javascript, you'd still need the cryptography expertise to verify it). By design, Signal doesn't depend on its serverside deployment for cryptographic security. That's not true of G Suite.

stubish 7y ago
You can verify what the binary did while you were watching. You can't verify what it did before, or what it will do next. OP said hostile and clever, and part of clever is only being hostile when nobody is watching. Apps that don't snoop constantly, delay transmissions, and hide transmissions in existing and expected communication channels are much harder to catch.
- tptacek 7y ago
  No, I'm saying, you can crack open the binary and see what it's capable of doing. If Signal wanted, it could obfuscate itself in various ways to make that hard, but (1) you'd notice that pretty quickly (that the code was hinky) and (2) Signal does not in fact want to do that. You personally might not be able to do that (but then, you personally might not be able to spot a defective authenticated key exchange either), but people can. Once someone spots the "Signal Backdoor", that's it for Signal. There's a lot of incentive to do that legwork. In contrast, G Suite could be comprehensively backdoored, and you'd have no way of knowing, no matter what your level of systems programming competence. I'm not saying they are backdoored; I rather doubt that they are, and I myself trust G Suite more than most other applications I use. But the point is, the trust you have to have in G Suite is different and more demanding than the trust you have to have in Signal.
  - stubish 7y ago
    This assumes that everyone gets the same binary, and the binary doesn't get updated. There is no reason that the binary delivered to your phone by the Google Play Store needs to be the same as the binary delivered to a reporter's phone. Even if we can trust the binary (and I agree, with Signal as the example we probably can), the application distribution mechanism and the underlying OS and its update mechanisms are still a problem.
    - kaoD 7y ago
      There are still mechanisms to mitigate reliance on trust. If you truly cared you wouldn't download it from Play Store and you wouldn't use a stock Android ROM. Of course that moves the problem up to the firmware level but the attack space is getting narrower. With G Suite you rely on trust from the ground up.
    - pvg 7y ago
      There is no reason that the binary delivered to your phone by the Google Play Store needs to be the same as the binary delivered to a reporter's phone. That's moving the goalposts to individual targeting, though. The individual targeting scenario is not that interesting because, as the winged quote from the technical literature goes, "YOU’RE STILL GONNA BE MOSSAD’ED UPON".

Wowfunhappy 7y ago

> As a security person I really can't think of any service (or piece of hardware) which I think satisfies the threat model where the provider is both clever and truly hostile. ...I can. Disconnect from the internet. It's a pain, and it won't be useful advice in many cases, but if you're a newsroom doing sensitive investigations on powerful individuals? I could make a case for it. Although, you'd want to ditch G Suite. (You can certainly think up clever attacks that work without internet, but disconnecting really does remove most vectors.)

dwighttk 7y ago

It may be that we never can say "Google employees aren't randomly snooping on your files." We shouldn't start saying it for things that prove nearby but entirely different things just because we won't ever be able to say it definitively.

millstone 7y ago

The threat model does not need to be that the provider as a whole is truly hostile. It could be "a rogue employee went snooping" or "the server got hacked" or "there was an access control bug." Instead of "trust us to keep your data", what if Google said "we don't have your data." That would give me more confidence, since it both makes the hostile actor's job much harder and it's also easier to verify.