Apple logging Messages contacts


The Intercept:

Every time you type a number into your iPhone for a text conversation, the Messages app contacts Apple servers to determine whether to route a given message over the ubiquitous SMS system, represented in the app by those déclassé green text bubbles, or over Apple's proprietary and more secure messaging network, represented by pleasant blue bubbles, according to the document. Apple records each query in which your phone calls home to see who's in the iMessage system and who's not.

Reportedly Apple regularly stores this metadata for 30 days, and could extend that if requested. This information would be subject to warrant requests from law enforcement. It's also important to know that the actual messages are encrypted using end-to-end encryption. This involves details around who you're contacting only while using Messages.

It's understandable what's going here since there needs to be a lookup to make Messages work. The sender device needs to know whether to send a message to Messages or SMS, and likely too gather keys to make the encryption to work.

The odd part is that Apple retains this information for a extended length of time. I'd guess, given the huge volume of Messages, Apple is caching this information to ease the load on their lookup servers. You can see this in action as messages to known contacts are instantly identified as a Messages user, while first time contacts take a bit to resolve to Messages.