TMO: A new class of attack on cipher misusing test infrastructure

Sk Subidh Ali, Ozgur Sinanoglu

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


We present a new class of scan attack on hardware implementation of ciphers. The existing scan attacks on ciphers exploit the Design for Testability (DfT) infrastructure of the implementation, where an attacker applies cipher inputs in the functional mode and then by switching to the test mode retrieves the secret key in the form of test responses. These attacks can be thwarted by applying a reset operation when there is a switch of mode. However, the mode-reset countermeasure can be thwarted by using only the test mode of a secure chip. In this work we show how a Test-Mode-Only (TMO) attack can overcome the constraints imposed by a mode-reset countermeasure and demonstrate TMO attacks on private key as well as public key ciphers.

Original languageEnglish (US)
Title of host publicationProceedings - 2015 IEEE 33rd VLSI Test Symposium, VTS 2015
PublisherIEEE Computer Society
ISBN (Electronic)9781479975976
StatePublished - Jun 1 2015
Event2015 33rd IEEE VLSI Test Symposium, VTS 2015 - Napa, United States
Duration: Apr 27 2015Apr 29 2015

Publication series

NameProceedings of the IEEE VLSI Test Symposium


Other2015 33rd IEEE VLSI Test Symposium, VTS 2015
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering


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