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Apple Explains How Secure iMessage Is

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Re: Apple Explains How Secure iMessage Is

#81

Post by rpdillon »

redthrowaway wrote: post #57
lawnchair_larry wrote: post #8

Author isn't very clever about crypto attacks. Sending device grabs all of the recipients public keys (as well as all of their own keys for other devices, which allows the conversation to be replicated on all of their own devices as well) hosted by Apple. Sending device has no way to verify those keys belong to the intended recipient . User has no way to verify which, or how many devices they are sending to. User doe…

>Apple wants to read your messages? They drop one of their public keys in the list. Apple gets a warrant? They drop the FBI's key in the list. If they were doing this, it would come out real quick. You'd just send a message to a different account you control then see how many keys you're getting/encrypted messages you're sending. Someone like Applebaum, who knows he's under surveillance and has the crypto/networking…

GP's point is sound: the weakness in public key crypto is key exchange. Unless you can independently verify that the keys you're getting from Apple belong to the intended recipient, the system doesn't work. You don't even have to add a key to the pool, you simply replace a key in the pool with a key generated by Apple, and when the message arrives on the server, it's decrypted and sent to anyone at all, and then re-encrypted with the recipient's key and sent along as normal. Even signatures aren't really a barrier in this case, since Apple can MITM your public key (used to verify the signature) to the recipient, as well.

Any crypto system whose security is predicated on a trusted server might as well be compromised. It's way too easy for servers to be subverted, either technologically or (il)legally.

Re: Apple Explains How Secure iMessage Is

#82

Post by rpdillon »

sjwright wrote: post #35

Obviously this system has limitations and entirely relies on your ability to trust Apple. But there's quite a few things to consider here: * Text messages and most other chat protocols require that you trust multiple hardware vendors, multiple software vendors, and multiple telcos. By comparison, iMessage only requires that you trust a single company, Apple. * As long as the operating system and messaging software is…

Among other things, the system requires you to not only trust Apple, but the hardware of the device itself. In particular, the random number generator in the iPhone/iPad, since the keys are generated on the device.

Re: Apple Explains How Secure iMessage Is

#84

Post by jsz0 »

lawnchair_larry wrote: post #8

Author isn't very clever about crypto attacks. Sending device grabs all of the recipients public keys (as well as all of their own keys for other devices, which allows the conversation to be replicated on all of their own devices as well) hosted by Apple. Sending device has no way to verify those keys belong to the intended recipient . User has no way to verify which, or how many devices they are sending to. User doe…

At a certain point people who are worried about the 'much else' part have to take personal responsibility for their paranoia. Apple cannot prove they aren't reading your iMessages. Maybe they are beaming them into deep space because they want to help aliens come get you. Who knows? It's hard to disprove. Anyone who reaches that level of paranoia should not be using these services.

Re: Apple Explains How Secure iMessage Is

#86

Post by iratedev »

aryastark wrote: post #73
Geee wrote: post #67

Earlier quoted context omitted.

Security is as strong as the weakest link. If there is a weak link there's no security. So, it is boolean.

Any more fuzzy platitudes for us, Geee? The best encryption we have today is still bound to time and technology. Without a threat model, it's pointless to discuss security. To the NSA, not much of anything is secure on the Internet. There is a lot you can do when you have total visibility into all traffic. But your psychotic girl/boyfriend who barely understands what Wi-Fi is? They probably won't be eavesdropping on…

They might be looking at your iMessages of your unlocked phone or your gmail account on the computer that you left yourself logged in on.

Again, the weakest point of any security is the human in the loop (read: you) that doesn't believe it can happen to them, regardless of how your data is accessed.

Re: Apple Explains How Secure iMessage Is

#88

Post by snotrockets »

kevinchen wrote: post #74
MBCook wrote: post #40

Earlier quoted context omitted.

It's still way better than SMS, and Facebook loves to use that kind of information to sell ads. This is actually more secure than I expected.

And it's far better than other messaging services where messages can be read by the server (e.g. Google talk). If they/the government wanted to read your messages, at last they'd have to jump through some hoops.

A single, very easily jumpable hoop: sending a lawyer to the nearest friendly judge, asking him/her to sign a warrant.

Re: Apple Explains How Secure iMessage Is

#89

Post by snotrockets »

pwnna wrote: post #4

They don't have to have your private key to pull off a MITM. In reality, it is probably secure enough against most adversaries. State level adversaries is a different story.. That you need OTR and key verification in person.

If the above reports of not Apple not pinning their certificate, then this isn't secure enough against any adversary that can compel or hack a CA to issue you a certificate in Apple's name. The latter appears to be not as hard as you might imagine.

And the recent fail in their SSL/TLS library means you don't even need the help of a CA to create a certificate Apple software would consider valid.

Re: Apple Explains How Secure iMessage Is

#90

Post by icebraining »

jsz0 wrote: post #84
lawnchair_larry wrote: post #8

Author isn't very clever about crypto attacks. Sending device grabs all of the recipients public keys (as well as all of their own keys for other devices, which allows the conversation to be replicated on all of their own devices as well) hosted by Apple. Sending device has no way to verify those keys belong to the intended recipient . User has no way to verify which, or how many devices they are sending to. User doe…

At a certain point people who are worried about the 'much else' part have to take personal responsibility for their paranoia. Apple cannot prove they aren't reading your iMessages. Maybe they are beaming them into deep space because they want to help aliens come get you. Who knows? It's hard to disprove. Anyone who reaches that level of paranoia should not be using these services.

Apple cannot prove they aren't reading your iMessages.

Sure they could. They could change the protocol and UI so that the users could verify and pin keys, and they could publish the iMessage source[1] to allow people to check it and compile it themselves.

Whether they should be expected to do these things is a different issue, but they could.

[1] not necessarily under a liberal license - for example, PGP was proprietary but allowed people to download its sources

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