It's confirmed, Apple's Feb14 security whitepaper states: "The encrypted chunks of the file are stored, without any user-identifying information, using third-p

It's confirmed, Apple's Feb14 security whitepaper states: "The encrypted chunks of the file are stored, without any user-identifying information, using third-party storage services, such as Amazon S3 and Windows Azure." But, as far as I know, they don't use Azure/Amazon for any non-storage functionality.