A lightweight hardware implementation of CRYSTALS-Kyber

The security of cryptographic algorithms based on integer factorization and discrete logarithm will be threatened by quantum computers in future.Since December 2016,the National Institute of Standards and Technology(NIST)has begun to solicit post-quantum cryptographic(PQC)algorithms worldwide.CRYSTALS-Kyber was selected as the standard of PQC algorithm after 3 rounds of evaluation.Meanwhile considering the large resource consumption of current implementation,this paper presents a lightweight architecture for ASICs and its implementation on FPGAs for prototyping.In this implementation,a novel compact modular multiplication unit(MMU)and compression/decompression module is proposed to save hardware resources.We put forward a specially optimized schoolbook polynomial multiplication(SPM)instead of number theoretic transform(NTT)core for polynomial multiplication,which can reduce about 74%SLICE cost.We also use signed number representation to save memory resources.In addition,we optimize the hardware implementation of the Hash module,which cuts off about 48%of FF consumption by register reuse technology.Our design can be implemented on Kintex-7(XC7K325T-2FFG900I)FPGA for prototyping,which occupations of 4777/4993 LUTs,2661/2765 FFs,1395/1452 SLICEs,2.5/2.5 BRAMs,and 0/0 DSP respective of client/server side.The maximum clock frequency can reach at 244 MHz.As far as we know,our design consumes the least resources compared with other existing designs,which is very friendly to resource-constrained devices.

High Thermoelectric Performance of Cu-Doped PbSe-PbS System Enabled by High-Throughput Experimental Screening

Recent advances in high-throughput(HTP)computational power and machine learning have led to great achievements in exploration of new thermoelectric materials.However,experimental discovery and optimization of thermoelectric materials have long relied on the traditional Edisonian trial and error approach.Herein,we demonstrate that ultrahigh thermoelectric performance in a Cu-doped PbSe-PbS system can be realized by HTP experimental screening and precise property modulation.Combining the HTP experimental technique with transport model analysis,an optimal Se/S ratio showing high thermoelectric performance has been efficiently screened out.Subsequently,based on the screened Se/S ratio,the doping content of Cu has been subtly adjusted to reach the optimum carrier concentration.As a result,an outstanding peak zT~1:6 is achieved at 873 K for a 1.8 at%Cu-doped PbSe_(0.6)S_(0.4) sample,which is the superior value among the n-type Te-free lead chalcogenides.We anticipate that current work will stimulate large-scale unitization of the HTP experimental technique in the thermoelectric field,which can greatly accelerate the research and development of new high-performance thermoelectric materials.

A general strategy for high-throughput experimental screening of promising bulk thermoelectric materials

High-throughput(HTP)experiments play key roles in accelerating the discovery of advanced materials,but the HTP preparation and characterization,especially for bulk samples,are extremely difficult.In this work,we developed a novel and general strategy for HTP screening of high-performance bulk thermoelectric materials.The performed fullchain HTP experiments cover rapid synthesis of the bulk sample with quasi-continuous composition,microarea phase identification and structure analysis,and measurement of the spatial distribution of the sample composition,electrical and thermal transport properties.According to our experiments,bulk Bi_(2-x)Sb_(x)Te_(3)(x=1-2)and Bi_(2)Te_(3-x)Se_(x)(x=0-1.5)samples with quasi-continuous compositions have been rapidly fabricated by this HTP method.The target thermoelectric materials with the best Sb/Bi and Te/Se ratios are successfully screened out based on subsequent HTP characterization results,demonstrating that this HTP technique is effective in speeding up the exploration of novel high-performance thermoelectric materials.