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> "Should the government be able to access citizen's digital data with a court order? And if so, how can that be enabled without compromising the general securi

> "Should the government be able to access citizen's digital data with a court order? And if so, how can that be enabled without compromising the general security of the device? IMO yes and here is how I'd implement this given a secure enclave: 1) Have Apple generate a device specific key that unlocks the device without pass code. 2) The key gets encrypted with an Apple held master key and printed on the inside of the device, e.g. a sticker on the chipset. Note that at this point, the device is as secure as before if we assume that someone who gets the Apple certifier key can exchange the secure enclave software at will. 3) Apple should ensure that the unencrypted key gets deleted from all of their systems after it was printed, to ensure plausible deniability. 4) The process for accessing the data on a specific device becomes simple - law enforcement needs to be in possession of (A) the device and (B) a court order. Apple will decrypt the key if forced by court order.

imrehg 11y ago
And if the Apple master key is ever revealed or stolen, everyone's phone can be decrypted. So yeah, this plan still compromises the general security of the device.
- m_mueller 11y ago
  As is the case with Apple's software certifier key. AFAIK this is what we currently have to assume since Apple doesn't specify how the update process for the secure enclave works. If this is the case it doesn't change anything, the certifier key is already like a master key.
  - pfg 11y ago
    Replacing the firmware (Secure Enclave or not) with a version that doesn't include rate-limits and auto-wipe isn't the same as having a crypto backdoor. Right now, your data is still protected by the complexity of your passphrase. This is not true for your scenario.
danieldk 11y ago
4) The process for accessing the data on a specific device becomes simple - law enforcement needs to be in possession of (A) the device and (B) a court order. Apple will decrypt the key if forced by court order. I think, we can assume that up till now, Apple has its private keys protected on some disconnected machine in a HSM, perhaps multiple HSMs, that are only accessible with very restricted access. When there is a gold iOS build, some of the key personal will go through a security procedure to get the build signed. Now suppose that such a procedure is put in place. And you get requests from US courts and Western European courts[1]. Once it's there, there will probably be hundreds, perhaps thousands of daily requests. It suddenly becomes undoable to keep the same security procedures. More people need access to the master key to handle all the requests for which there is a court order. Or even worse: there has to be an semi-automated procedure to handle such requests. In any case, any such procedure will weaken the security of iOS devices significantly. Since Apple's master key is so extremely valuable, it will be an extremely attractive target for attacks (in the semi-automatic scenario); or it's easier to find a corrupt person to leak the keys. Since people store anything from personal photos, access to bank accounts, to business plans on their phones, we should move into the direction of making crypto systems stronger, not intentionally weakening them. [1] Let's avoid the slippery slope that this would trigger for not-so-nice regimes for a moment. Although, once such a backdoor is there, it will happen.
- m_mueller 11y ago
  I concede, these are good points. I'd like to add though, that it would be better overall to have a solution that at least tries to limit access to specific devices, rather than Apple being forced by the government to build in general backdoors. But I can't really think of a better solution. Maybe have a hierarchy of keys, one per some serial number suffix, each in different servers in different buildings and accessed by different people, so if one gets lost it at least only affects a fraction of devices on the market?
  - danieldk 11y ago
    I think that we as a society (though I am not American) should decide first whether we think backdoors for court orders are worth the risk at all. Let's be honest with ourselves, the chance to be killed by terrorists is minuscule compared to other factors that are under human control (air pollution, traffic incidents, homicides). If you are looking at non-terrorist criminal activity, one has to wonder if you don't have more serious problems than unlocking a bunch of iPhones when your homicide rates[1] or traffic-related deaths[2] are higher than nearly any other Western country. Terrorism and crime are just easy distractions to get more power. [1] https://en.wikipedia.org/wiki/List_of_countries_by_intentional_homicide_rate https://en.wikipedia.org/wiki/List_of_countries_by_intention... [2] https://en.wikipedia.org/wiki/List_of_countries_by_traffic-related_death_rate https://en.wikipedia.org/wiki/List_of_countries_by_traffic-r...
yaur 11y ago
No. Whatever backdoor you enable for the US government can be used by other governments. When traveling internationally I would rather just deal with the minuscule increase in terrorism risk in exchange for a phone that can't be decrypted by anyone but me.

imrehg 11y ago

And if the Apple master key is ever revealed or stolen, everyone's phone can be decrypted. So yeah, this plan still compromises the general security of the device.

m_mueller 11y ago
As is the case with Apple's software certifier key. AFAIK this is what we currently have to assume since Apple doesn't specify how the update process for the secure enclave works. If this is the case it doesn't change anything, the certifier key is already like a master key.
- pfg 11y ago
  Replacing the firmware (Secure Enclave or not) with a version that doesn't include rate-limits and auto-wipe isn't the same as having a crypto backdoor. Right now, your data is still protected by the complexity of your passphrase. This is not true for your scenario.

danieldk 11y ago

4) The process for accessing the data on a specific device becomes simple - law enforcement needs to be in possession of (A) the device and (B) a court order. Apple will decrypt the key if forced by court order. I think, we can assume that up till now, Apple has its private keys protected on some disconnected machine in a HSM, perhaps multiple HSMs, that are only accessible with very restricted access. When there is a gold iOS build, some of the key personal will go through a security procedure to get the build signed. Now suppose that such a procedure is put in place. And you get requests from US courts and Western European courts[1]. Once it's there, there will probably be hundreds, perhaps thousands of daily requests. It suddenly becomes undoable to keep the same security procedures. More people need access to the master key to handle all the requests for which there is a court order. Or even worse: there has to be an semi-automated procedure to handle such requests. In any case, any such procedure will weaken the security of iOS devices significantly. Since Apple's master key is so extremely valuable, it will be an extremely attractive target for attacks (in the semi-automatic scenario); or it's easier to find a corrupt person to leak the keys. Since people store anything from personal photos, access to bank accounts, to business plans on their phones, we should move into the direction of making crypto systems stronger, not intentionally weakening them. [1] Let's avoid the slippery slope that this would trigger for not-so-nice regimes for a moment. Although, once such a backdoor is there, it will happen.

m_mueller 11y ago
I concede, these are good points. I'd like to add though, that it would be better overall to have a solution that at least tries to limit access to specific devices, rather than Apple being forced by the government to build in general backdoors. But I can't really think of a better solution. Maybe have a hierarchy of keys, one per some serial number suffix, each in different servers in different buildings and accessed by different people, so if one gets lost it at least only affects a fraction of devices on the market?
- danieldk 11y ago
  I think that we as a society (though I am not American) should decide first whether we think backdoors for court orders are worth the risk at all. Let's be honest with ourselves, the chance to be killed by terrorists is minuscule compared to other factors that are under human control (air pollution, traffic incidents, homicides). If you are looking at non-terrorist criminal activity, one has to wonder if you don't have more serious problems than unlocking a bunch of iPhones when your homicide rates[1] or traffic-related deaths[2] are higher than nearly any other Western country. Terrorism and crime are just easy distractions to get more power. [1] https://en.wikipedia.org/wiki/List_of_countries_by_intentional_homicide_rate https://en.wikipedia.org/wiki/List_of_countries_by_intention... [2] https://en.wikipedia.org/wiki/List_of_countries_by_traffic-related_death_rate https://en.wikipedia.org/wiki/List_of_countries_by_traffic-r...

yaur 11y ago

No. Whatever backdoor you enable for the US government can be used by other governments. When traveling internationally I would rather just deal with the minuscule increase in terrorism risk in exchange for a phone that can't be decrypted by anyone but me.