Prime+Count: Novel Cross-world Covert Channels on ARM TrustZone

Haehyun Cho, Penghui Zhang, Donguk Kim, Jinbum Park, Choong Hoon Lee, Ziming Zhao, Adam Doupé, Gail Joon Ahn

Research output: Chapter in Book/Report/Conference proceedingConference contribution

30 Scopus citations


The security of ARM TrustZone relies on the idea of splitting system-on-chip hardware and software into two worlds, namely normal world and secure world. In this paper, we report cross-world covert channels, which exploit the world-shared cache in the TrustZone architecture. We design a Prime+Count technique that only cares about how many cache sets or lines have been occupied. The coarser-grained approach significantly reduces the noise introduced by the pseudo-random replacement policy and world switching. Using our Prime+Count technique, we build covert channels in single-core and cross-core scenarios in the TrustZone architecture. Our results demonstrate that Prime+Count is an effective technique for enabling cross-world covert channels on ARM TrustZone.

Original languageEnglish (US)
Title of host publicationProceedings of the 3rd International Workshop on Advanced Interconnect Solutions and Technologies for Emerging Computing Systems, AISTECS 2018
PublisherAssociation for Computing Machinery
Number of pages12
ISBN (Electronic)1595930361, 9781450364430
StatePublished - Jan 22 2018
Event34th Annual Computer Security Applications Conference, ACSAC 2018 - San Juan, United States
Duration: Dec 3 2018Dec 7 2018

Publication series

NameACM International Conference Proceeding Series


Conference34th Annual Computer Security Applications Conference, ACSAC 2018
Country/TerritoryUnited States
CitySan Juan


  • ARM TrustZone
  • Cache side-channel
  • Covert channels

ASJC Scopus subject areas

  • Software
  • Human-Computer Interaction
  • Computer Vision and Pattern Recognition
  • Computer Networks and Communications


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