Should I use the same Apple ID for iCloud and the iTunes store?
My immediate assumption was "sure, of course, keep it simple", but today I read the following recommendation:
One potential problem that users of Apple’s iCloud and other services can easily fall into is the overuse of a single account across the services used on their devices—for example, using the same Apple ID for both iCloud and the iTunes store. The iTunes store links your credit card data to your Apple ID for music and application purchases, as well as in-app purchases. It stores your contact information and address as well. So it’s a potential source of even bigger headaches if it’s exposed along with your iCloud account.
… with the obvious implication that you should not use the same Apple ID for both iCloud and the iTunes store. So, what is the best practice? What are the tradeoffs?
Related: Are there disadvantages to using different Apple IDs for iCloud and Store purchases?; Is it a bad idea to have a shared Apple ID for purchases that also is used for iCloud?; How many Apple IDs should one household have?. However, those questions do not address security concerns.
Best Answer
In any of the common scenarios in which you store your Store credentials on devices under the control of others, it makes good security sense to have those be different from the ones you use for iCloud.
For example, it is common to share music among family members by using an Apple ID for purchases on all of the family's machines. If that Apple ID were the same as the one you used for iCloud, then (unless you can be sure that all family members have secured their machines) anyone who got his hands on one of those machines could potentially gain access to your e-mail, calendar, and documents (and, in typical configurations, could even log on to your machine if he had access to it).