Apple informs us that iMessages are encrypted and anonymous—and as far as we know, that’s true. But it may not tell the whole story: iMessages may create a log of phone numbers, including ones you never actually message.
According to a document obtained by The Intercept, typing a number into an iPhone for a text conversation causes the Messages app to contact Apple servers. This is to determine when the message will take place over SMS or Apple’s proprietary network (green bubble vs. blue bubble). But that data log also includes the date and time a user entered the number as well as their IP address. And Apple may turn this data over in response to court orders.
This data is recorded even if you never actually message that contact. You only need to enter the full number to ping Apple’s servers with your information.
Apple says this data is only stored for 30 days, but still—it’s a little worrying that so much private data is being logged on Apple servers while using a platform designed to be secure and anonymous.