Wednesday, September 9, 2015

Apple Tangles With U.S. Over iMessage Data Access

Matt Apuzzo, et al. (via Christopher Soghoian):

With Apple, the encryption and decryption are done by the phones at either end of the conversation; Apple does not keep copies of the message unless one of the users loads it into iCloud, where it is not encrypted. (In the drug and gun investigation this summer, Apple eventually turned over some stored iCloud messages. While they were not the real-time texts the government most wanted, officials said they saw it as a sign of cooperation.)

What they mean here is that iCloud backups, which are enabled by default, are not encrypted. So, as I’ve said, it’s pretty much irrelevant that the iMessage communications themselves are encrypted end-to-end. Unlike with USB syncing, there is no way to make an encrypted cloud backup of an iPhone. Nor is there a way to do a cloud backup that excludes iMessage data.

Matthew Green:

It’s a vague headline that manages to obscure the real thrust of the story, which is that according to reporters at the Times, Apple has not been forced to backdoor their popular encrypted iMessage system. This flies in the face of some rumors to the contrary.


While it seems pretty obvious that Apple could in theory substitute keys and thus enable eavesdropping, in practice it may require substantial changes to Apple’s code. And while there are a few well-known cases in which the government has forced companies to turn over keys, changing the operation of a working system is a whole different ball of wax.

Ben R.

Apple controls iPhones. They have root access, you don’t. It’s the future that Richard Stallman predicted in The Right To Read, except he thought it would be Microsoft. In this kind of situation, why would you even mention key substitution attacks? It’s like speculating about the owners of an Internet café implementing a TLS MITM attack in their own network’s router in order to spy on HTTPS connections originating from their own machines. Why bother when you’re root?

Update (2015-09-12): Bruce Schneier:

The rumor I am hearing is not about access to a particular user and his communications. It is about general access to iOS data and communications. And it’s in the FISA court, which means that it’s not a domestic criminal matter.

1 Comment RSS · Twitter

"In this kind of situation, why would you even mention key substitution attacks?"

It's even worse than that. With a NSL, Apple would be legally gagged from mentioning it, even if they did want to for whatever unimaginable reason.

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