The iOS Security Model

Apple has incorporated four layers of security in iOS to protect the user and their data.
Device Security
Techniques to prevent an unauthorized individual from using the device.
Data Security
Techniques to protect the data stored on the device, even if the device is stolen.
Network Security
Tools to encrypt data while it is in transit across a network.
Application Security
Mechanisms to secure the operating system and isolate applications while they are running.

All security in iOS i start learning from Hacking and Securing iOS Application E-Book.

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