A New Paradigm in Split Manufacturing: Lock the FEOL, Unlock at the BEOL

Split manufacturing was introduced as an effective countermeasure against hardware-level threats such as IP piracy, overbuilding, and insertion of hardware Trojans. Nevertheless, the security promise of split manufacturing has been challenged by various attacks, which exploit the well-known working principles of physical design tools to infer the missing BEOL interconnects. In this work, we advocate a new paradigm to enhance the security for split manufacturing. Based on Kerckhoff's principle, we protect the FEOL layout in a formal and secure manner, by embedding keys. These keys are purposefully implemented and routed through the BEOL in such a way that they become indecipherable to the state-of-the-art FEOL-centric attacks. We provide our secure physical design flow to the community. We also define the security of split manufacturing formally and provide the associated proofs. At the same time, our technique is competitive with current schemes in terms of layout overhead, especially for practical, large-scale designs (ITC'99 benchmarks).Comment: DATE 2019 (https://www.date-conference.com/conference/session/4.5

Concerted Wire Lifting: Enabling Secure and Cost-Effective Split Manufacturing

Here we advance the protection of split manufacturing (SM)-based layouts through the judicious and well-controlled handling of interconnects. Initially, we explore the cost-security trade-offs of SM, which are limiting its adoption. Aiming to resolve this issue, we propose effective and efficient strategies to lift nets to the BEOL. Towards this end, we design custom "elevating cells" which we also provide to the community. Further, we define and promote a new metric, Percentage of Netlist Recovery (PNR), which can quantify the resilience against gate-level theft of intellectual property (IP) in a manner more meaningful than established metrics. Our extensive experiments show that we outperform the recent protection schemes regarding security. For example, we reduce the correct connection rate to 0\% for commonly considered benchmarks, which is a first in the literature. Besides, we induce reasonably low and controllable overheads on power, performance, and area (PPA). At the same time, we also help to lower the commercial cost incurred by SM.Comment: Published in Proc. Asia South Pac. Des. Autom. Conf. (ASPDAC) 201

Rethinking Split Manufacturing: An Information-Theoretic Approach with Secure Layout Techniques

Split manufacturing is a promising technique to defend against fab-based malicious activities such as IP piracy, overbuilding, and insertion of hardware Trojans. However, a network flow-based proximity attack, proposed by Wang et al. (DAC'16) [1], has demonstrated that most prior art on split manufacturing is highly vulnerable. Here in this work, we present two practical layout techniques towards secure split manufacturing: (i) gate-level graph coloring and (ii) clustering of same-type gates. Our approach shows promising results against the advanced proximity attack, lowering its success rate by 5.27x, 3.19x, and 1.73x on average compared to the unprotected layouts when splitting at metal layers M1, M2, and M3, respectively. Also, it largely outperforms previous defense efforts; we observe on average 8x higher resilience when compared to representative prior art. At the same time, extensive simulations on ISCAS'85 and MCNC benchmarks reveal that our techniques incur an acceptable layout overhead. Apart from this empirical study, we provide---for the first time---a theoretical framework for quantifying the layout-level resilience against any proximity-induced information leakage. Towards this end, we leverage the notion of mutual information and provide extensive results to validate our model.Comment: Published in Proc. International Conference On Computer Aided Design (ICCAD) 2017; [v2] minor fix Fig 11: avg area overhead for g-type2 was miscalculated; [v3] added DOI to PDF foote

Nonmonotonic energy harvesting efficiency in biased exciton chains

We theoretically study the efficiency of energy harvesting in linear exciton chains with an energy bias, where the initial excitation is taking place at the high-energy end of the chain and the energy is harvested (trapped) at the other end. The efficiency is characterized by means of the average time for the exciton to be trapped after the initial excitation. The exciton transport is treated as the intraband energy relaxation over the states obtained by numerically diagonalizing the Frenkel Hamiltonian that corresponds to the biased chain. The relevant intraband scattering rates are obtained from a linear exciton-phonon interaction. Numerical solution of the Pauli master equation that describes the relaxation and trapping processes, reveals a complicated interplay of factors that determine the overall harvesting efficiency. Specifically, if the trapping step is slower than or comparable to the intraband relaxation, this efficiency shows a nonmonotonic dependence on the bias: it first increases when introducing a bias, reaches a maximum at an optimal bias value, and then decreases again because of dynamic (Bloch) localization of the exciton states. Effects of on-site (diagonal) disorder, leading to Anderson localization, are addressed as well.Comment: 9 pages, 6 figures, to appear in Journal of Chemical Physic

Early cretaceous palynomorphs from the zuata area, eastern Venezuela

Este trabalho é baseado em estudos palinológicos e petrográficos do testemunho de um poço (MARAVEN, S. A.) situado na área de Zuata, Venezuela. Os palinomorfos recuperados são atribuídos a 19 gêneros e 33 espécies de esporos e 9 gêneros e 26 espécies de pólen. A idade indicada é, mais provavelmente, ?Aptiano-Albiano médio inferior. São feitas comparações com modelos já estabelecidos de províncias microflorísticas do Cretáceo Inferior (BRENNER, 1976; HERNGREEN, 1976, 1981) e as implicações discutidas. Estudos palinológicos e sedimentológicos sugerem um ambiente de deposição fluvial, sob condições áridas, numa região topograficamente pouco movimentadaThis report is based on palynological and petrographical studies of a core from a Zuata área well (MARAVEN, S. A.). Palynomorphs encountered have been assigned to 19 genera and 33 species of spores and 9 genera and 26 species of pollen grains. The most probable age is ?Aptian-Early Middle Albian. A comparison with previously published Early Cretaceous microfloral province concepts (BRENNER, 1976; HERNGREEN, 1976, 1981) has been made and implications are discussed. Palynological and sedimentological studies suggest a fluvial environment in arid conditions on a flat topograph

Graph Neural Networks for Hardware Vulnerability Analysis -- Can you Trust your GNN?

The participation of third-party entities in the globalized semiconductor supply chain introduces potential security vulnerabilities, such as intellectual property piracy and hardware Trojan (HT) insertion. Graph neural networks (GNNs) have been employed to address various hardware security threats, owing to their superior performance on graph-structured data, such as circuits. However, GNNs are also susceptible to attacks. This work examines the use of GNNs for detecting hardware threats like HTs and their vulnerability to attacks. We present BadGNN, a backdoor attack on GNNs that can hide HTs and evade detection with a 100% success rate through minor circuit perturbations. Our findings highlight the need for further investigation into the security and robustness of GNNs before they can be safely used in security-critical applications.Comment: Will be presented at 2023 IEEE VLSI Test Symposium (VTS