Fingerprint Confidential

Q:

I want to buy an iPhone 5s, but how can I disable the fingerprint-recognition feature so it doesn’t send my prints over the Internet where somebody might steal them?

A:

First of all, the fingerprint-recognition feature, which allows you to unlock your phone with just a touch instead of a password, is off by default. Unless you turn it on and then train it to recognize your fingers, it doesn’t operate and you can just keep typing in a password, or use no lock method at all.

Secondly, Apple says the fingerprint data never leaves your phone, never goes onto the Internet and never even is backed up to the cloud. Instead, Apple says, it is stored in a secure area of the phone’s processor chip, and the scanner checks with this stored data — not with any online database — to decide whether your finger matches the stored parameters.

Q:

I notice that on the new iPhone operating system, the phone downloads many more emails at one time, making it much more difficult to mark them as read. Is there a way around this?

A:

Yes. In a mailbox, or the combined inbox, you just tap “Edit” at the upper right, then tap “Mark All” at the lower left. Then choose “Mark As Read” from the pop-up menu and all your messages should be marked as read.

Q:

Is the new iPhone 5s compatible with Ford’s Sync system for music and phone calling in the car?

A:

I asked a Ford spokesman and he said: “Ford expects to provide our Apple customers with full compatibility for Sync v3.6.” And I can report that, while I don’t own a Ford, the iPhone 5s I tested was able to make and receive phone calls, stream music over Bluetooth or via a cable, and transmit text messages to my new-model car.

Write to Walt at mossberg@wsj.com.