Apple Platform Security
- Welcome
- Intro to Apple platform security
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- Encryption and Data Protection overview
- Passcodes and passwords
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- Data Protection overview
- Data Protection
- Data Protection classes
- Keybags for Data Protection
- Protecting keys in alternate boot modes
- Protecting user data in the face of attack
- Sealed Key Protection (SKP)
- Activating data connections securely in iOS and iPadOS
- Role of Apple File System
- Keychain data protection
- Digital signing and encryption
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- Services security overview
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- Apple Pay security overview
- Apple Pay component security
- How Apple Pay keeps users’ purchases protected
- Payment authorization with Apple Pay
- Paying with cards using Apple Pay
- Contactless passes in Apple Pay
- Rendering cards unusable with Apple Pay
- Apple Card security
- Apple Cash security
- Tap to Pay on iPhone
- Secure Apple Messages for Business
- FaceTime security
- Glossary
- Document revision history
- Copyright

Express Cards with power reserve
If iOS isn’t running because iPhone needs to be charged, there may still be enough power in the battery to support Express Card transactions. Supported iPhone devices automatically support this feature with:
A payment or transit card designated as the Express Transit card
Student ID cards with Express Mode turned on
Car keys with Express Mode turned on
Home keys with Express Mode turned on
Hospitality or Corporate access cards with Express Mode turned on
Pressing the side button (or on iPhone SE 2nd generation, the Home button) displays the low-battery icon as well as text indicating that Express Cards are available to use. The NFC controller performs Express Card transactions under the same conditions as when iOS is running, except that transactions are indicated only with haptic notification (no visible notification is shown). On iPhone SE 2nd generation, completed transactions may take a few seconds to appear on screen. This feature isn’t available when a standard user-initiated shutdown is performed.