If you use Passbook frequently on your iPhone, you may have noticed that certain passes use your location in order to give you easy access on your lock screen to a specific pass when you're within the vicinity. Some of those passes may contain personal information or allow for someone to charge an item to a gift card or account.

If you'd like to prevent unauthorized access to your passes, you can easily do so within Passbook. Follow along and we'll show you how.

If you've got a passcode set on your iPhone, Siri and Passbook will still work by default on your lock screen. This means that anyone who wants to talk to Siri or use one of your passes will still be able to. While it's convenient, it can be a bit unsafe. If you prefer having to use your passcode in order to access them, you can do so easily with a simple settings change.

Here's how.