A Comprehensive Test Pattern Generation Approach Exploiting SAT Attack for Logic Locking

The need for reducing manufacturing defect escape in today's safety-critical applications requires increased fault coverage. However, generating a test set using commercial automatic test pattern generation (ATPG) tools that lead to zero-defect escape is still an open problem. It is challenging to detect all stuck-at faults to reach 100% fault coverage. In parallel, the hardware security community has been actively involved in developing solutions for logic locking to prevent IP piracy. Locks (e.g., XOR gates) are inserted in different locations of the netlist so that an adversary cannot determine the secret key. Unfortunately, the Boolean satisfiability (SAT) based attack, introduced in [1], can break different logic locking schemes in minutes. In this paper, we propose a novel test pattern generation approach using the powerful SAT attack on logic locking. A stuck-at fault is modeled as a locked gate with a secret key. Our modeling of stuck-at faults preserves the property of fault activation and propagation. We show that the input pattern that determines the key is a test for the stuck-at fault. We propose two different approaches for test pattern generation. First, a single stuck-at fault is targeted, and a corresponding locked circuit with one key bit is created. This approach generates one test pattern per fault. Second, we consider a group of faults and convert the circuit to its locked version with multiple key bits. The inputs obtained from the SAT tool are the test set for detecting this group of faults. Our approach is able to find test patterns for hard-to-detect faults that were previously failed in commercial ATPG tools. The proposed test pattern generation approach can efficiently detect redundant faults present in a circuit. We demonstrate the effectiveness of the approach on ITC'99 benchmarks. The results show that we can achieve a perfect fault coverage reaching 100%.Comment: 12 pages, 7 figures, 5 table

G9a Is Essential for EMT-Mediated Metastasis and Maintenance of Cancer Stem Cell-Like Characters in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a particularly aggressive cancer with poor prognosis, largely due to lymph node metastasis and local recurrence. Emerging evidence suggests that epithelial-to-mesenchymal transition (EMT) is important for cancer metastasis, and correlated with increased cancer stem cells (CSCs) characteristics. However, the mechanisms underlying metastasis to lymph nodes in HNSCC is poorly defined. In this study, we show that E-cadherin repression correlates with cancer metastasis and poor prognosis in HNSCC. We found that G9a, a histone methyltransferase, interacts with Snail and mediates Snail-induced transcriptional repression of E-cadherin and EMT, through methylation of histone H3 lysine-9 (H3K9). Moreover, G9a is required for both lymph node-related metastasis and TGF-β-induced EMT in HNSCC cells since knockdown of G9a reversed EMT, inhibited cell migration and tumorsphere formation, and suppressed the expression of CSC markers. Our study demonstrates that the G9a protein is essential for the induction of EMT and CSC-like properties in HNSCC. Thus, targeting the G9a-Snail axis may represent a novel strategy for treatment of metastatic HNSCC

Evidence for e+e−→γχc1,2e^+e^-\to\gamma\chi_{c1, 2} at center-of-mass energies from 4.009 to 4.360 GeV

Using data samples collected at center-of-mass energies of $\sqrt{s}$ = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process $e^+e^-\to\gamma\chi_{cJ}$ $(J = 0, 1, 2)$ and find evidence for $e^+e^-\to\gamma\chi_{c1}$ and $e^+e^-\to\gamma\chi_{c2}$ with statistical significances of 3.0$\sigma$ and 3.4$\sigma$, respectively. The Born cross sections $\sigma^{B}(e^+e^-\to\gamma\chi_{cJ})$, as well as their upper limits at the 90% confidence level are determined at each center-of-mass energy.Comment: 8 pages, 7 figures, 3 table

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Complexity Analysis of the SAT Attack on Logic Locking

Due to the adoption of horizontal business models following the globalization of semiconductor manufacturing, the overproduction of integrated circuits (ICs) and the piracy of intellectual properties (IPs) can lead to significant damage to the integrity of the semiconductor supply chain. Logic locking emerges as a primary design-for-security measure to counter these threats, where ICs become fully functional only when unlocked with a secret key. However, Boolean satisfiability-based attacks have rendered most locking schemes ineffective. This gives rise to numerous defenses and new locking methods to achieve SAT resiliency. This paper provides a unique perspective on the SAT attack efficiency based on conjunctive normal form (CNF) stored in SAT solver. First, we show how the attack learns new relations between keys in every iteration using distinguishing input patterns and the corresponding oracle responses. The input-output pairs result in new CNF clauses of unknown keys to be appended to the SAT solver, which leads to an exponential reduction in incorrect key values. Second, we demonstrate that the SAT attack can break any locking scheme within linear iteration complexity of key size. Moreover, we show how key constraints on point functions affect the SAT attack complexity. We explain why proper key constraint on AntiSAT reduces the complexity effectively to constant 1. The same constraint helps the breaking of CAS-Lock down to linear iteration complexity. Our analysis provides a new perspective on the capabilities of SAT attack against multiplier benchmark c6288, and we provide new directions to achieve SAT resiliency

AFIA: ATPG-Guided Fault Injection Attack on Secure Logic Locking

The outsourcing of the design and manufacturing of integrated circuits has raised severe concerns about the piracy of Intellectual Properties and illegal overproduction. Logic locking has emerged as an obfuscation technique to protect outsourced chip designs, where the circuit netlist is locked and can only be functional once a secure key is programmed. However, Boolean Satisfiability-based attacks have shown to break logic locking, simultaneously motivating researchers to develop more secure countermeasures. In this paper, we present a novel fault injection attack to break any locking technique that relies on a stored secret key, and denote this attack as AFIA, ATPG-guided Fault Injection Attack. The proposed attack is based on sensitizing a key bit to the primary output while injecting faults at a few other key lines that block the propagation of the targeted key bit. AIFA is very effective in determining a key bit as there exists a stuck-at fault pattern that detects a stuck-at 1 (or stuck-at 0) fault at any key line. The average complexity of number of injected faults for AFIA is linear with the key size and requires only |K| test patterns to determine a secret key, K. AFIA requires a fewer number of injected faults to sensitize a bit to the primary output, compared to 2|K|-1 faults for the differential fault analysis attack [26].Comment: arXiv admin note: text overlap with arXiv:2007.1051

Effects of soluble soybean polysaccharide as filling agent on the properties of leathers

Content: Soluble soybean polysaccharide (SSPS) is good in emulsification, and stable emulsion may be formed with the addition of SSPS in fatliquoring agents. In this paper, with wet blues as raw materials, after being retanned and neutralized, fatliquoring and filling up with SSPS were carried out at the same time, with different amounts of SSPS, i.e., 1%, 3%, 5%,7% in weight. The leather samples were dried at room temperature. The effects of SSPS amounts on the thickness, air permeability and water vapor permeability of the crust leather were studied. The tensile properties of the leathers filled by SSPS were analyzed. The results indicated that with increasing the amounts of SSPS, the thickness and the water vapor permeability of the leathers increase, while the air permeability decreases slightly. The maximum stress-strain capacity of leathers decreases with increasing the SSPS amount. At the SSPS amount of 3%, the leather is good in softness, as well as in physical and mechanical properties. Take-Away: 1.SSPS from soybean dregs is an acidic polysaccharide, which is rich in raw materials and low in cost. 2.Leathers filled with SSPS have good performance

Effects of soluble soybean polysaccharide as filling agent on the properties of leathers

Content: Soluble soybean polysaccharide (SSPS) is good in emulsification, and stable emulsion may be formed with the addition of SSPS in fatliquoring agents. In this paper, with wet blues as raw materials, after being retanned and neutralized, fatliquoring and filling up with SSPS were carried out at the same time, with different amounts of SSPS, i.e., 1%, 3%, 5%,7% in weight. The leather samples were dried at room temperature. The effects of SSPS amounts on the thickness, air permeability and water vapor permeability of the crust leather were studied. The tensile properties of the leathers filled by SSPS were analyzed. The results indicated that with increasing the amounts of SSPS, the thickness and the water vapor permeability of the leathers increase, while the air permeability decreases slightly. The maximum stress-strain capacity of leathers decreases with increasing the SSPS amount. At the SSPS amount of 3%, the leather is good in softness, as well as in physical and mechanical properties. Take-Away: 1.SSPS from soybean dregs is an acidic polysaccharide, which is rich in raw materials and low in cost. 2.Leathers filled with SSPS have good performance

Effects of soluble soybean polysaccharide as filling agent on the properties of leathers

Content: Soluble soybean polysaccharide (SSPS) is good in emulsification, and stable emulsion may be formed with the addition of SSPS in fatliquoring agents. In this paper, with wet blues as raw materials, after being retanned and neutralized, fatliquoring and filling up with SSPS were carried out at the same time, with different amounts of SSPS, i.e., 1%, 3%, 5%,7% in weight. The leather samples were dried at room temperature. The effects of SSPS amounts on the thickness, air permeability and water vapor permeability of the crust leather were studied. The tensile properties of the leathers filled by SSPS were analyzed. The results indicated that with increasing the amounts of SSPS, the thickness and the water vapor permeability of the leathers increase, while the air permeability decreases slightly. The maximum stress-strain capacity of leathers decreases with increasing the SSPS amount. At the SSPS amount of 3%, the leather is good in softness, as well as in physical and mechanical properties. Take-Away: 1.SSPS from soybean dregs is an acidic polysaccharide, which is rich in raw materials and low in cost. 2.Leathers filled with SSPS have good performance

Highly Stabilized Ni-Rich Cathode Material with Mo Induced Epitaxially Grown Nanostructured Hybrid Surface for High-Performance Lithium-Ion Batteries

Capacity fading induced by unstable surface chemical properties and intrinsic structural degradation is a critical challenge for the commercial utilization of Ni-rich cathodes. Here, a highly stabilized Ni-rich cathode with enhanced rate capability and cycling life is constructed by coating the molybdenum compound on the surface of LiNi 0.815 Co 0.15 Al 0.035 O 2 secondary particles. The infused Mo ions in the boundaries not only induce the Li 2 MoO 4 layer in the outermost but also form an epitaxially grown outer surface region with a NiO-like phase and an enriched content of Mo 6+ on the bulk phase. The Li 2 MoO 4 layer is expected to reduce residential lithium species and promote the Li + transfer kinetics. The transition NiO-like phase, as a pillaring layer, could maintain the integrity of the crystal structure. With the suppressed electrolyte-cathode interfacial side reactions, structure degradation, and intergranular cracking, the modified cathode with 1% Mo exhibits a superior discharge capacity of 140 mAh g -1 at 10 C, a superior cycling performance with a capacity retention of 95.7% at 5 C after 250 cycles, and a high thermal stability