2-Bromo-1-phenyl­ethanone

The title compound, C8H7BrO, is a halogenated derivative of acetophenone. The mol­ecule shows noncrystallographic Cs symmetry. The intra­cyclic C—C—C angles cover the range 118.8 (2)–120.4 (3)°. In the crystal structure, C—H⋯O contacts connect the mol­ecules into undulating sheets perpendicular to the crystallographic c axis

Design, Evaluation and Optimization of Physical Unclonable Functions based on Transient Effect Ring Oscillators

International audienceThis paper proposes a theoretical study and a full overview of the design, evaluation and optimization of a PUF based on transient element ring oscillators (TERO-PUF). We show how, by following some simple design rules and strategies, designers can build and optimize a TERO-PUF with state of the art PUF characteristics in a standard CMOS technology. To this end, we analyzed the uniqueness, steadiness and randomness of responses generated from 30 test chips in a CMOS 350nm process in nominal and corner voltage and temperature conditions. Response generation schemes are proposed and discussed to optimize the PUF performances and reduce its area without noticeable loss in its output quality. In particular, we show that the large area of the basic blocks in the TERO-PUF is balanced by the high level of entropy extracted in each basic block. Guidelines are provided to balance reliability and randomness of the responses and the design area

Enhanced TERO-PUF design and characterization with FPGA

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Enhanced TERO-PUF Implementations and Characterization on FPGAs

International audiencePhysical unclonable functions (PUF) are a promising approach in design for trust and security. A PUF derives a unique identifier using physical characteristics of different dies containing an identical circuit, so it can be used to authenticate chips and for identification. The transient effect ring oscillator (TERO) PUF is based on the extraction of entropy due to process variations by comparing TERO cells characteristics. The TERO cell is designed and implemented with a symmetric structure that requires special selection of the gates used and the delays of all connections inside the cell. Implementing this cell in FPGAs is challenging because the structure of FPGAs does not automatically allow designers to choose connections between elements. However, by manually specifying constraints and using specific features of the target FPGA family, the symmetry of the TERO cell can be established and reproduced in larger designs. In this work, the design of the TERO cell is described for two different FGPA technologies (45nm Xilinx Spartan 6 and 28nm Altera Cyclone V). The statistical characterization of the TERO-PUF with the two targeted FPGAs has resulted in a uniqueness of 48.46% with Spartan 6 and 47.62% with Cyclone V. The result for the steadiness is 2.63% with Spartan 6 and 1.8% with Cyclone V. These results are close to the results obtained by several works that use ring oscillator RO-PUF which are considered the best candidate for PUF implementation on FPGAs. However, TERO-PUF is less sensitive to electromagnetic analysis than RO-PUF. Additionally, unlike RO-PUF, TERO-PUF is able to generate multiple bits per challenge (from one to three) and we have shown during the statistical characterization that the TERO-PUF provides from 0.85 to 1 bits of entropy per response bit.As a conclusion, our work clearly shows that TERO-PUF is an serious alternative to RO-PUF for PUF implementation on FPGAs with strong statistical characteristics and more security than RO-PUF

Design and Characterization of the TERO-PUF on SRAM FPGAs

International audiencePhysical unclonable functions (PUF) are a promising approach in design for trust and security. A PUF derives a unique identifier for different similar dies using some of their physical characteristics, so it can be used to authenticate chips and to fight against counterfeiting and theft of devices. The transient effect ring oscillator (TERO) PUF is based on the extraction of the entropy of the process variations by comparison between TERO cells characteristics. This TERO cell needs to be carefully designed in order to construct a PUF. This task needs to be done with precision, especially in the size of used gates and in the delays of all connections inside the cell. This is particularly challenging in FPGA. This paper presents the design of TERO cells in two FPGA families: Xilinx Spartan 6 and Altera Cyclone V. Additionally, results of the characterization of the TEROPUF are presented and compared for the two technologies. The reproducibility of experimental results are guaranteed by the online access to all design files

Area-oriented comparison of lightweight block ciphers implemented in hardware for the activation mechanism in the anti-counterfeiting schemes

International audienceOver the past 10 years, the multitude of highly constrained applications such as radio-frequency identification and sensor networks has led to a new trend in the development of cryptographic primitives. Many algorithms categorized as lightweight cryptographic algorithms have been developed specifically for these new applications. Comparing them is very important but also very challenging because every application has its own constraints. This fact leads to a different choice of design strategies, and the best algorithm for one application is not necessarily the best for all applications. Moreover, the definition of what is lightweight is not always the same because lightweight covers a reduction in power and energy consumption just as well as a reduction in area for hardware. This article proposes and compares lightweight hardware implementations of four recent block ciphers (Klein, Led, Lilliput, and Ktantan). This work is included in a large project that aims to protect the hardware against cloning and counterfeiting. The main constraint in this field is the area required by the protection scheme. As a result, we chose to target only the smallest possible area for each selected algorithm. Consequently, two strategies are presented: full width and serial hardware implementations. All results were generated and verified for Xilinx Spartan-6 and Spartan-3 field-programmable gate arrays and also for application-specific integrated circuit. Additionally, all the design files are available online

2H-Chromen-4(3H)-one

In the title compound, C9H8O2, a benzo-annulated heterocyclic ketone, the non-aromatic six-membered ring adopts an E2 conformation. In the crystal, C—H...O contacts connect the molecules into double sheets perpendicular to the crystallographic a axis. The centroid–centroid distance for two π-systems is 3.7699 (6) Å

Ultra-Lightweight Implementation in Area of Block Ciphers

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