On: Law Enforcement Is Accessing Locked Devices

[mcphage]

> I thought iPhone's will lock you out for a certain amount of time after a certain amount of failed attempts.

One of the techniques used is, copying the memory from your phone onto another phone, and then testing passwords on that. When it locks up, wipe it and recopy. I don't know if that is still used, however.

[Shivetya → mcphage]

(out of my league here)

why not copy memory to another device and run a crack against a segment of the memory known to hold specific values until you match? I am not sure if they can block taking encrypted data off a device.

So my question is, case intrusion. Can this be detected in various forms in order to render the contents of the device useless? The safety factor to the owner is that they would have backed up the device to a trusted source before they voluntarily submitted a phone to being physically opened. you would need to not only check for separation but drilling through either side.

[jmt_ → mcphage]

Conceptually that makes sense to me but if you're already locked out of the phone how would you access the memory in the first place?

[WJW → jmt_]

Open up the phone, solder leads to the memory bus?

EDIT: If you can access the real time clock chip and set the clock to a point in the future where the lockout has elapsed, that might work as well.

[dboreham → WJW]

No. The memory in question is inside a special chip designed explicitly for the purpose of not allowing easy access.

[WJW → dboreham]

Not allowing "easy" access is not the same as "no" access though. I could easily imagine a radar/MRI imaging system generating instructions for a cnc drilling rig that would make micrometer accurate holes through the chip packaging, then inserting extremely precise probes directly into the wires inside the package.

I could also imagine a team of 5-10 engineers making such a system in a year (total costs <10 million), with 20-50 million in off-the-shelf hardware costs as a pessimistic estimate. As a company, you then "only" have to amortize this cost over 20 countries each wishing to crack the phones of 5 phones of high-profile criminals and/or dissidents each to get to an average cost of 600k per phone. It would easily be worth that much to the US to crack the phone of a high profile drug lord.

Long story short, private companies (even with as much resources as Apple) either need watertight mathematical proofs of security or accept that they stand no chance at all against nation state adversaries.