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Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

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Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#71

Post by soheil »

Dylan16807 wrote: post #40
koolba wrote: post #35

Full disk encryption (FDE) is a UX issue, not a technical one. You don't need a secure cryptographic processor, but the UX sucks without one. A simple, working, FDE setup would be something like LUKS running at boot: 1. Turn on phone 2. Phone loads up initial bootstrap OS 3. Phone prompts user for master key 4. Master key is used to unlock volume 5. Regular OS boot continues If the master key has enough entropy, brut…

On the other hand, phones do not need to be rebooted often. And if I'm upgrading my OS the stupid thing is going to make me wait 20 minutes while it precompiles every app, so screw it I don't care if I have to spend 40 seconds inputting a password.

Sometimes collection agencies rotate their phone numbers when they call you so you can't block them, the only way to turn off the phone.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#72

Post by shawnz »

soheil wrote: post #71
Dylan16807 wrote: post #40

Earlier quoted context omitted.

On the other hand, phones do not need to be rebooted often. And if I'm upgrading my OS the stupid thing is going to make me wait 20 minutes while it precompiles every app, so screw it I don't care if I have to spend 40 seconds inputting a password.

Sometimes collection agencies rotate their phone numbers when they call you so you can't block them, the only way to turn off the phone.

You could turn off notifications, or use airplane mode.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#73

Post by ComodoHacker »

koolba wrote: post #35

Full disk encryption (FDE) is a UX issue, not a technical one. You don't need a secure cryptographic processor, but the UX sucks without one. A simple, working, FDE setup would be something like LUKS running at boot: 1. Turn on phone 2. Phone loads up initial bootstrap OS 3. Phone prompts user for master key 4. Master key is used to unlock volume 5. Regular OS boot continues If the master key has enough entropy, brut…

>Full disk encryption (FDE) is a UX issue, not a technical one.

Most of the secutity is pretty much a UX issue. Otherwise century-old one-time pad would fit all.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#74

Post by snassar »

616c wrote: post #52

So out of curiosity, as someone who has a nontrivial passcode on his Android device that people constantly mock, how many characters are we talking to be safe. I have known for a long time 4 digit numeric PINs are stupid. Sadly the San Bernadino case, for all the wrong reasons, taught me all the alternative auth methods are just as risky. Should I be worried? I don't know. But as a long time Android enthusiast and po…

A friend saw me entering my longish, non-trivial passphrase into my android phone and commented that I must not have many friends if I have to enter this passphrase every time to use my phone.

For a moment I was torn between being proud in my passphrase and sad at my lack of friends.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#75

Post by laginimaineb »

pdimitar wrote: post #55
laginimaineb wrote: post #8

Earlier quoted context omitted.

I'll definitely try and get around to it sometime soon. However, I wouldn't be surprised if the situation is the same... After all, the KeyMaster module was initially only meant to keep encryption keys on the device, not to safeguard FDE.

Sorry for an extremely nooby question, but your comment makes me wonder: Are Snapdragon and Exynos architectures that alike? I mean, do you have any preliminary idea how easy it would be to apply your Snapdragon method to an Exynos SoC?

Actually, I would imagine they are nothing like one another.

However, Exynos uses a TrustZone TEE implementation to implement the KeyMaster module, just like Qualcomm's Snapdragon. This means that unless that TEE implementation uses a hardware key which is not software accessible, the same issue would be present. Of course, reverse-engineering a new TEE implementation would take a long time... But it sounds like it could be fun.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#76

Post by Pxtl »

wyldfire wrote: post #69
Pxtl wrote: post #57

Earlier quoted context omitted.

A ring or bracelet with an NFC tag in it. Well, a ring is probably too small for a proper NFC tag, but either way: NFC jewellery.

They absolutely make rings w/NFC tags. At least men's rings, I assume they may do it for women's too.

Neat. Does android support NFC for the bootup FDE decrypt?

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#78

Post by ysleepy »

nickik wrote: post #64

I would use a longer password. But currently the unlock and the encryption password are always the same. That one of the issue I would like to see changed. I would also like to have more fine grained rules on when I can unlock with a fingerprint, when pin and when I should be forced to put in the encryption password. Additionally I would like to use U2F NFC token on my keychain as a second factor for unlock (if I hav…

You can make it use long FDE passwords and a pattern by hackery. Some sqlite fiddling necessary. See XDA.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#79

Post by gcr »

snassar wrote: post #74
616c wrote: post #52

So out of curiosity, as someone who has a nontrivial passcode on his Android device that people constantly mock, how many characters are we talking to be safe. I have known for a long time 4 digit numeric PINs are stupid. Sadly the San Bernadino case, for all the wrong reasons, taught me all the alternative auth methods are just as risky. Should I be worried? I don't know. But as a long time Android enthusiast and po…

A friend saw me entering my longish, non-trivial passphrase into my android phone and commented that I must not have many friends if I have to enter this passphrase every time to use my phone. For a moment I was torn between being proud in my passphrase and sad at my lack of friends.

You bring up an interesting UX issue.

If I need to be constantly available to my friends, "number of seconds to a text reply" is something that I need to minimize.

Longer passphrases prevent me from sending quick replies.

Re: Extracting Qualcomm's KeyMaster Keys – Breaking Android Full Disk Encryption

#80

Post by Zigurd »

haikuginger wrote: post #53
kyrra wrote: post #44

Earlier quoted context omitted.

For what it's worth, the "optimizing apps" thing is going away in Android N. https://developer.android.com/preview/api-overview.html#jit_...

I do find it somewhat amusing that Android went from Dalvik precompiled to Dalvik JIT, to ART precompiled, to ART JIT.

Dalvik interpreted was the first step. You could sort of call it "precompiled" if you call dex a precompiler.
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