Clock-modulation based watermark for protection of embedded processors

Jedrzej Kufel, Peter Wilson, Stephen Hill, Bashir Al-Hashimi, Paul N. Whatmough, James Myers

Research output: Contribution to conferencePaperpeer-review

2 Citations (SciVal)
223 Downloads (Pure)


This paper presents a novel watermark generation technique for the protection of embedded processors. In previous work, a load circuit is used to generate detectable watermark patterns in the ASIC power supply. This approach leads to hardware area overheads. We propose removing the dedicated load circuit entirely, instead to compensate the reduced power consumption the watermark power pattern is emulated by reusing existing clock gated sequential logic as a zero-overhead load circuit and modulating the clock-gating enable signal with the watermark sequence. The proposed technique has been validated through experiments using two ASICs in 65nm CMOS, one with an ARM Cortex-M0 microcontroller and one with a Cortex-A5 microprocessor. Silicon measurement results verify the viability of the technique for embedded processors. Furthermore, the proposed clock modulation technique demonstrates a significant area reduction, without compromising the detection performance. In our experiments an area overhead reduction of 98$% was achieved. Through reuse of existing logic and reduction of watermark hardware implementation costs, the proposed clock modulation technique offers an improved robustness against removal attacks
Original languageEnglish
Pages1 - 6
Number of pages6
Publication statusPublished - 2014
EventDesign, Automation and Test in Europe Conference and Exhibition (DATE), 2014 - Germany, Dresden, Germany
Duration: 24 Mar 201428 Mar 2014


ConferenceDesign, Automation and Test in Europe Conference and Exhibition (DATE), 2014


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