Hierarchical functional obfuscation of integratec circuits using a mode-based approach

Sandhya Koteshwara, Chris H. Kim, Keshab K. Parhi

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

4 Scopus citations


Hardware obfuscation has been proposed as a hardware security measure against reverse engineering, intellectual property (IP) piracy and integrated circuits (IC) overbuilding. In this paper, we present a novel method of obfuscation using a hierarchical approach. In the design flow, IP vendors obfuscate their designs using a set of keys and provide these keys to the design house. The design house then integrates all the IPs and adds its own keys to create a complete obfuscated system. This prevents both misuse of IPs and illegal use of ICs since only secure parties have access to the correct keys. The obfuscation at each level is performed using a mode-based approach in which the design can operate in meaningful and non-meaningful modes. The design is functionally correct in only one mode. An attacker needs to work through different levels of the design to correctly decipher its operation and correct working mode. Since each of the IPs can work in multiple meaningful modes, the attack becomes more difficult as the number of IPs increases. These ideas are demonstrated using a convolution architecture with fast Fourier transform (FFT) blocks. With only about 13% area and 15% power overhead over an unobfuscated design, it is shown that the proposed design has the flexibility to be obfuscated with different key sizes and overheads depending on the level of security.

Original languageEnglish (US)
Title of host publicationIEEE International Symposium on Circuits and Systems
Subtitle of host publicationFrom Dreams to Innovation, ISCAS 2017 - Conference Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781467368520
StatePublished - Sep 25 2017
Event50th IEEE International Symposium on Circuits and Systems, ISCAS 2017 - Baltimore, United States
Duration: May 28 2017May 31 2017

Publication series

NameProceedings - IEEE International Symposium on Circuits and Systems
ISSN (Print)0271-4310


Other50th IEEE International Symposium on Circuits and Systems, ISCAS 2017
Country/TerritoryUnited States

Bibliographical note

Funding Information:
This research has been supported in part by the National Science Foundation under grant number CNS-1441639 and the Semiconductor Research Corporation under contract number 2014-TS-2560

Publisher Copyright:
© 2017 IEEE.


  • Hardware obfuscation
  • Hardware security
  • Hierarchical obfuscation
  • Reverse engineering


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