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Physical attacks can compromise the security of cryptographic devices. Depending on the attack’s requirements, adversaries might need to (i) place probes in the proximity of the integrated circuits (ICs) package, (ii) create physical connections between their probes/wires and the system’s PCB, or (iii) physically tamper with the PCB’s components, chip’s package, or substitute the entire PCB to prepare the device for the attack. While tamper-proof enclosures prevent and detect physical access to the system, their high manufacturing cost and incompatibility with legacy systems make them unattractive for many low-cost scenarios. In this paper, inspired by methods known from the field of power integrity analysis, we demonstrate how the impedance characterization of the system’s power distribution network (PDN) using on-chip circuit-based network analyzers can detect various classes of tamper events. We explain how these embedded network analyzers, without any modifications to the system, can be deployed on FPGAs to extract the frequency response of the PDN. The analysis of these frequency responses reveals different classes of tamper events from board to chip level. To validate our claims, we run an embedded network analyzer on FPGAs of a family of commercial development kits and perform extensive measurements for various classes of PCB and IC package tampering required for conducting different side-channel or fault attacks. Using the Wasserstein Distance as a statistical metric, we further show that we can confidently detect tamper events. Our results, interestingly, show that even environment-level tampering activities, such as the proximity of contactless EM probes to the IC package or slightly polished IC package, can be detected using on-chip impedance sensing.
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Electrons Vs. Photons: Assessment of Circuit’s Activity Requirements for E-Beam and Optical Probing Attacks
Contactless probing methods through the chip backside have been demonstrated to be powerful attack techniques in the field of electronic security. However, these attacks typically require the adversary to run the circuit under specific conditions, such as enforcing the switching of gates or registers with certain frequencies or repeating measurements over multiple executions to achieve an acceptable signal-to-noise ratio (SNR). Fulfilling such requirements may not always be feasible due to challenges such as low-frequency switching or inaccessibility of the control signals. In this work, we assess these requirements for contactless electron- and photon-based probing attacks by performing extensive experiments. Our findings demonstrate that E-beam probing, in particular, has the potential to outperform optical methods in scenarios involving static or low-frequency circuit activities.
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- Award ID(s):
- 2150123
- PAR ID:
- 10476812
- Publisher / Repository:
- ASM International
- Date Published:
- Page Range / eLocation ID:
- 339 to 345
- Format(s):
- Medium: X
- Location:
- Phoenix, Arizona, USA
- Sponsoring Org:
- National Science Foundation
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