This means nothing without the full source code to prove it.
Apple Explains How Secure iMessage Is
31–40 of 126 posts
Re: Apple Explains How Secure iMessage Is
#32The way Apple could "read" the messages is by sending a keybag down to the person sending the messages with another public key, one that Apple holds the private key for. For example if you have 3 devices (iPhone, iPad, MBP) and someone goes to send you a message, they have to re-encrypt the message three times because Apple would have sent them three public keys. Now if Apple were evil because of a government order,…
Lawful intercept isn't evil.
When there are secret courts and laws, it is evil. It is indistinguishable from the surveillance state.
Re: Apple Explains How Secure iMessage Is
#33Author 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…
Well, classic key distribution problem is classic. You have to anchor your trust somewhere. And whatever you choose, somebody will complain.
Cue web of trust PSA.
Re: Apple Explains How Secure iMessage Is
#34More so that its rivals, Apple has consistently put forth a greater effort to explain their technology to its customers. Apple has remained keen to point out the difficulties of hardware and software development. Perhaps this is one reason why people outside of the technology sector perceive Apple products as superior. People think Apple has gone the extra mile.
Re: Apple Explains How Secure iMessage Is
#35Obviously 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 closed source, it would be impossible to eliminate the requirement to trust Apple anyway. If you really need serious security, you shouldn't be relying on any closed source third party systems, period.
* This is about as secure as it could ever get without requiring users to be educated about security principles. Given that iMessage is foremost a seamless alternative to text messages, it's difficult to imagine how they could make it more secure without compromising utility.
* The implementation details mean that any Government snooping must be done with Apple's knowledge, and will require the blessing of Apple's legal department. This might not be a particularly high bar to cross, but it does mean that Governments aren't running rampant, analyzing every message sent.
* The United States government isn't the only bad actor out there. The level of security appears to be extremely good against entities that hold no sway with Apple's legal team. It's also presumably impervious to a hostile network, or hostile foreign governments.
Re: Apple Explains How Secure iMessage Is
#36It's worth re-reading this post by Matthew Green, "Can Apple read your iMessages?" [1]
For one, if you back up your device with iCloud, then yes, Apple can read your iMessages. This has been verified by experiment.
Second, Apple operates a central directory of iMessage public keys mapped to accounts, and this enables various kinds of MiTM attacks. Contrast this with the way TextSecure / RedPhone does contact discovery using blinded signature queries [2].
Third, iMessage and iOS are closed source. Ultimately, closed source can do whatever the heck it wants. Not just what they're telling you it does.
All the same, we now have some new details on iMessage from Apple [3], and I'm looking forward to hearing the crypto experts pick it apart.
[1] http://blog.cryptographyengineering.com/2013/06/can-apple-re...
[2] https://whispersystems.org/blog/contact-discovery/
[3] http://images.apple.com/iphone/business/docs/iOS_Security_Fe...
Re: Apple Explains How Secure iMessage Is
#37Author 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…
Well, classic key distribution problem is classic. You have to anchor your trust somewhere. And whatever you choose, somebody will complain. Cue web of trust PSA.
Well, maybe not. Web of Trust has serious scaling issues.
https://bitcointalk.org/oldSiteFiles/byzantine.html
Blockchain based key distribution may let you anchor trust to a decentralized process.
Re: Apple Explains How Secure iMessage Is
#38Earlier quoted context omitted.
Users get both a push notification and email when a new device is added to the key bag. So additionally this step would need to be maliciously skipped.
That would only be the case if someone does it by logging in to your iCloud account, which applies to none of these attack scenarios. Even then, it only notifies the owner of that account, not the party who is sending messages to unverified keys. If you're spoofing the keyserver, it's invisible to Apple. If you're the FBI and serving a warrant on Apple, Apple does not send the message telling you that "FBI's MacBook…
Pardon my ignorance not being a security expert, but given that all endpoints here (software and hardware) are Apple-controlled, just how trivial is spoofing a keyserver? Genuinely curious.
Re: Apple Explains How Secure iMessage Is
#39Earlier quoted context omitted.
Actually, is it not possible to do a count on the key bag?
A custom-written third party client could theoretically do this (and mitigate most of the other attacks here). What Apple provides won't help with this though. Think of an SSH client that never verifies host keys and never warns you when they change. That's basically what iMessage is.
Even a custom-written third party client still doesn't eliminate the requirement to trust Apple. They're delivering your closed source operating system, which could very easily include hostile behaviors like key logging and screen recording.
At least with iMessage, the entire ecosystem is managed by one company, so you only have to trust one company.
Re: Apple Explains How Secure iMessage Is
#40It's worth re-reading this post by Matthew Green, "Can Apple read your iMessages?" [1] For one, if you back up your device with iCloud, then yes, Apple can read your iMessages. This has been verified by experiment. Second, Apple operates a central directory of iMessage public keys mapped to accounts, and this enables various kinds of MiTM attacks. Contrast this with the way TextSecure / RedPhone does contact discover…
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.