XART

From The Apple Wiki

eXtendable Anti-Replay Tokens. Stylized as xART.


Introduction

https://en.wikipedia.org/wiki/Replay_attack https://papers.put.as/papers/ios/2019/blackhat-2019-crlmhg-v4.pdf


Use in Apple Processors

  • T2 (A10 base) has xART in sideband data
  • A11 and higher have on-package EEPROM for anti-replay
  • mART in iOS 12 and prior, xART in iOS 13 and up

Interfacing with xART

In recovery the xART can be reset with `xartutil`