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Why can't Apple decrypt your iPhone?

blog.cryptographyengineering.com

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Re: Why can't Apple decrypt your iPhone?

#61

Post by girvo »

abalone wrote: post #49

There's another technical surveillance method here that I feel more people should be talking about: monitoring iMessage communication. iMessage is extremely secure[1], except for the fact that Apple controls the device list for iCloud accounts. The method would simply be for Apple to silently add another device to a target's account which is under law enforcement's control. I say "silently" in that they would need to…

> by looking at how many devices iMessage is sending copies to when messaging the target

Is iMessage centralised? I'm pretty certain it is, and if that is the case then you couldn't find out if you were tapped or not; one message gets sent to the server (perhaps with a list of the devices you want to send it to) and the server under Apple/LEO control sends a copy to their "device".

Re: Why can't Apple decrypt your iPhone?

#62

Post by rietta »

philip1209 wrote: post #14

> (Apple pegs such cracking attempts at 5 1/2 years for a random 6-character password consisting of lowercase letters and numbers. PINs will obviously take much less time, sometimes as little as half an hour. Choose a good passphrase!) Do not use simple pin passwords on your phone. In particular, if you use fingerprint access, there is no reason not to have a long, complex password.

There is an argument against using the fingerprint access and that is that a user gives up the right of consent while in custody. If law enforcement gets a judicial order to forcibly press the prisoner's finger to the sensor to unlock the device, then he or she has little recourse as the right to remain silent is not implicated. One cannot be similarly physically compelled to disclose a code only held in his or her memory.

Re: Why can't Apple decrypt your iPhone?

#63

Post by girvo »

RexRollman wrote: post #54
jacquesm wrote: post #46

Earlier quoted context omitted.

That's quite possibly no longer a theoretical scenario at this point. It would really surprise me if you were the first person to think of that trick (it's pretty obvious) and that + gag orders would do nicely. Parallel construction to plug any holes in case someone wises up that this is already done in practice.

Parallel construction has to be one of the most unconstitutional things I have ever heard of. It's fraud and perjury.

But but but... they're criminals! The ends justify the means, right?

/s

Re: Why can't Apple decrypt your iPhone?

#64

Post by girvo »

rietta wrote: post #62
philip1209 wrote: post #14

> (Apple pegs such cracking attempts at 5 1/2 years for a random 6-character password consisting of lowercase letters and numbers. PINs will obviously take much less time, sometimes as little as half an hour. Choose a good passphrase!) Do not use simple pin passwords on your phone. In particular, if you use fingerprint access, there is no reason not to have a long, complex password.

There is an argument against using the fingerprint access and that is that a user gives up the right of consent while in custody. If law enforcement gets a judicial order to forcibly press the prisoner's finger to the sensor to unlock the device, then he or she has little recourse as the right to remain silent is not implicated. One cannot be similarly physically compelled to disclose a code only held in his or her m…

> One cannot be similarly physically compelled to disclose a code only held in his or her memory.

Are you sure? In the UK and I'm pretty sure in my native Australia, they definitely can, under pain of "contempt of court".

Re: Why can't Apple decrypt your iPhone?

#65

Post by exhilaration »

Spearchucker wrote: post #33
opendais wrote: post #30

Earlier quoted context omitted.

The problem is the attack surface for an app on a device vs. in the wild is much, much larger and much, much less secure. Once its on your phone, it can just screenshot things if nothing else.

I wrote myself a database that I use for passwords and the like. I get around this by masking text until I tap a button, and then waiting a random number of ticks before decrypting the value and progressively unmasking the text. It takes between ½ and two seconds. The problem I've yet to solve is hiding the text. Leaving it on-screen for, say 10 seconds before re-masking and encrypting is fine for now but sometimes t…

You should try 1Password: https://agilebits.com/onepassword

It's the most recommended password manager on Hacker News.

Re: Why can't Apple decrypt your iPhone?

#66

Post by rhino369 »

girvo wrote: post #64
rietta wrote: post #62

Earlier quoted context omitted.

There is an argument against using the fingerprint access and that is that a user gives up the right of consent while in custody. If law enforcement gets a judicial order to forcibly press the prisoner's finger to the sensor to unlock the device, then he or she has little recourse as the right to remain silent is not implicated. One cannot be similarly physically compelled to disclose a code only held in his or her m…

> One cannot be similarly physically compelled to disclose a code only held in his or her memory. Are you sure? In the UK and I'm pretty sure in my native Australia, they definitely can, under pain of "contempt of court".

In the US it depends. If they know you had child porn on your phone they can force it. If they just suspect you have child porn, they can't.

Re: Why can't Apple decrypt your iPhone?

#67

Post by dmishe »

giovannibajo1 wrote: post #19
tzs wrote: post #17

If someone obtains your phone, and prevents you from initiating a remote wipe (perhaps they have you in custody, or perhaps they have isolate the phone so that it cannot receive the wipe command), it sounds like this technology will do a good job of preventing them from decrypting your data from the phone if you have a decent passcode. They cannot throw GPUs or FPGAs or clusters or other custom hardware at the proble…

Yes, currently iCloud backups are not encrypted so they can be extracted by law enforcement, but on the other hand they are not mandatory, as Apple also offers a full local backup solution through iTunes (albeit, admittedly, they could make it work automatically like Time Machine, instead of manually; I guess they'll get there, now that they're using privacy in marketing). On the other hand, it is perfectly possible…

But Apple says "iCloud secures the content [backups] by encrypting it when sent over the Internet, storing it in an encrypted format, and using secure tokens for authentication"

Re: Why can't Apple decrypt your iPhone?

#68

Post by hwatson »

girvo wrote: post #61
abalone wrote: post #49

There's another technical surveillance method here that I feel more people should be talking about: monitoring iMessage communication. iMessage is extremely secure[1], except for the fact that Apple controls the device list for iCloud accounts. The method would simply be for Apple to silently add another device to a target's account which is under law enforcement's control. I say "silently" in that they would need to…

> by looking at how many devices iMessage is sending copies to when messaging the target Is iMessage centralised? I'm pretty certain it is, and if that is the case then you couldn't find out if you were tapped or not; one message gets sent to the server (perhaps with a list of the devices you want to send it to) and the server under Apple/LEO control sends a copy to their "device".

Each message is encrypted individually for each device that will be receiving the message. As a result, unless Apple slip a public key they have control over into the keys reported for the receiver, they cannot read your messages. (This is why abalone mentions that Apple do not have access to your old messages.)

http://blog.quarkslab.com/imessage-privacy.html goes into detail as to how the key exchange process works.

Re: Why can't Apple decrypt your iPhone?

#69

Post by yeukhon »

Two questions:

* Regarding the fixed 80ms timing: has there been study on the average time needed (aside from the WHY 80ms instead of 70ms or 90ms). I also want to ask for clarification: where is the entire PBKDF2-AES is done? On the AES engine (which I believe is part of the A7 chip)? On a TPM chip (which might be a NO based on unauthenticed source [1])?

* So this UID created in every device and stored in Secure Enclaved which there is a dedicated path between SE and AES engine. But can we conduct any side-channel attack? I am pretty noob with hardware security.

Re: Why can't Apple decrypt your iPhone?

#70

Post by josefonseca »

tptacek wrote: post #58
josefonseca wrote: post #56

> Apple doesn't use scrypt. Their approach is to add a 256-bit device-unique secret key called a UID to the mix, and to store that key in hardware where it's hard to extract from the phone. Apple claims that it does not record these keys nor can it access them. Technically, this is where it breaks down. As in "Trust me I don't store the keys." If that hypothesis is true(they don't store these keys), then they'll have…

Right. We'd instead be having a discussion about how Atmel can decrypt your phone.

It was just an example how you could detach the secret and the device made by Apple. I'm sure there are better ideas for that. The way this is configured now Apple can decrypt any phone, which voids the argument made in the OP. But I can understand why this will be the unpopular opinion here.
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