The NSA have hooks in various data centers and internet backbones. They collect the intel indirectly giving the companies plausible deniability.
However the private keys have to deployed, on scale. So if as someone here is suggesting the NSA has infiltrated those companies, they could have got those keys and just decrypt the stream.
I wouldn’t bet my money on that… but it’s more likely than breaking the encryption, and if they can get military secrets, I guess they could get the keys.
Also those companies could have just volunteered them—that’s where the emphasis on ‘direct’ access comes in.
The suggestion that the companies actually gave them the keys and this explains the "direct access" phrase makes a lot of sense!
I mean Apple only got added in 2011. If what you're saying is true then what does this date refer to?
Well, if they are intercepting data through backbones, and much of that data is encrypted, they need to defeat the encryption in a durable way to get a clear feed. While I don't suggest that this is what was going on, if it was, there would be know reason that each provider would necessarily be broken at the same time; there would likely both be prioritization of resources directed at each provider, differences in the security of each provider, and chance involved as to when each was broken.
Growing popularity and usage of icloud and apple's own messaging system? iirc, before icloud, Apple didn't have that much user data.