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World Journal of Clinical Cases 2025年第3期13卷 42-49页

作者： Na Li Yue-Yue Ren Ying Tang Qi Yang tian-tian Meng Song Li Jing Zhang Stomatological Hospital and College Anhui Medical UniversityHefei 230032Anhui ProvinceChina Department of Endodontics The Affiliated Stomatological Hospital of Xuzhou Medical UniversityXuzhou 221000Jiangsu ProvinceChina

BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in *** SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical *** the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival ***-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival *** This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.

关键词： Complicated crown-root fracture Multiple root fracture Spontaneous healing Cone-beam computed tomography Long-term follow-up Case report

New Insights into Divide-and-Conquer Attacks on the Round-Reduced Keccak-MAC

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Chinese Journal of Electronics 2019年第4期28卷 698-705页

作者： YE Chendong tian tian National Digital Switching System Engineering and Technological Research Center

Keccak is the final winner of SHA-3 competition and it can be used as message authentic codes as well. The basic and balanced divide-and-conquer attacks on Keccak-MAC were proposed by Dinur et *** Eurocrypt 2015. The idea of cube attacks is used in the two attacks to divide key bits into small portions. By carefully analysing the mappings used in Keccak-MAC, it is found that some cube variables could divide key bits into smaller portions and so better divide-and-conquer attacks are obtained. In order to evaluate the resistance of Keccak-MAC against divide-and-conquer attacks based on cubes, we theoretically analyse the lower bounds of the complexities of divide-and-conquer attacks. It is shown that the lower bounds of the complexities are still not better than those of the conditional cube tester proposed by Senyang Huang et al.. This indicates that KeccakMAC can resist the divide-and-conquer attack better than the conditional cube tester. We hope that these techniques still could provide some new insights on the future cryptanalysis of Keccak.

关键词： Keccak-MAC Divide-and-conquer attacks Cube attacks

A Low-Complexity Key-Recovery Attack on 6-Round Midori64

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Journal of Systems Science & Complexity 2023年第4期36卷 1738-1756页

作者： XIE Xiaofeng tian tian Information Engineering University Zhengzhou 450001China

In EUROCRYPT 2017,a new structure-difference property,say“a-multiple-of-8”was proposed on 5-round *** by the idea,yoyo attacks and mixture differential attacks were proposed yielding new records on data and computational complexities for key-recovery attacks against 5-round *** this paper,the authors attempt to apply the idea of mixture differential cryptanalysis to *** is a lightweight block cipher proposed at ASIACRYPT *** the structure of Midori is similar to AES,the MixColumn matrix of Midori is not *** on this observation,the authors present a class of deterministic differential trails on 2-round *** combined with the yoyo trick,a new type of 4-round retracing boomerang distinguishers is obtained on *** on the new 4-round distinguishers,a key-recovery attack on 6-round Midori64 is given that requires only 2^(27)computational complexity,2^(29)chosen plaintexts,2^(20)adaptively chosen *** key-recovery attack has been experimentally verified.

关键词： Boomerang attack Midori mixture differential attack yoyo attack

A New Method for Searching Cubes and Its Application to 815-Round Trivium

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Journal of Systems Science & Complexity 2023年第5期36卷 2234-2254页

作者： LIU Chen tian tian QI Wenfeng PLA Strategic Support Force Information Engineering University Zhengzhou 450001China

The cube attack proposed by Dinur and Shamir is one of the most important key-recovery attacks against *** division property based cube attacks have been extensively studied and significantly *** particular,the MILP modeling technique for the three-subset division property without unknown subset proposed by Hao,et *** EUROCRYPT 2020 and the new technique with nested monomial predictions proposed by Hu,et *** ASIACRYPT 2021 are best techniques to recover exact superpolies in division property based cube ***,at this state of the art,whether a superpoly can be recovered in division property based cube attacks is mainly decided by the scale of the superpoly,that is,the number of *** the choice for proper cubes corresponding to low-complexity superpolies is more critical *** effective cube construction methods were proposed for experimental cube attacks,but not applicable to division property based cube *** this paper,the authors propose a heuristic cube criterion and a cube sieve algorithm,which can be combined with the three-subset division property to recover a number of *** to815-round Trivium,the authors recovered 417 superpolies from 441 cubes obtained by our algorithm of sizes between 41 and *** success rate is 94.56%.There are 165 non-constant superpolies with degree less than *** order to demonstrate the significance of the new algorithm,the authors tested the best superpoly recovery technique at EUROCRYPT 2020 using random cubes of similar sizes on 815-round *** experimental result shows that no cube could be completely recovered within a given period of time because the superpolies for random cubes are too complex.

关键词： Cube attacks division property key-recovery attacks trivium

Differential Fault Attack on the Stream Cipher LIZARD

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Chinese Journal of Electronics 2021年第3期30卷 534-541页

作者： MA Zhen tian tian QI Wenfeng National Digital Switching System Engineering Technological Research Center

In this paper, we try to give a security evaluation of LIZARD stream cipher in regard to fault attacks, which, to the best of our knowledge, is the first fault analysis on LIZARD. We design a differential engine of LIZARD to track the differential trail of the keystreams. It is shown that the distributions of the keystream differences are heavily biased. Utilizing this characteristic, we propose an improved method to identify the fault location for LIZARD whose success probability approaches 1. Then we use the fault-free keystream and faulty keystreams to generate system of equations in internal state variables and solve it by SAT solver. The result shows that with 100 keystream bits, only 6 different faults are needed to recover the internal state. Finally,the comparison between LIZARD and Grain v1 shows that LIZARD is more resistable than Grain v1 in regard to fault attacks.

关键词： cryptography fault tolerant computing probability keystream differences faulty keystreams differential fault attack LIZARD stream cipher fault attacks fault analysis differential trail fault-free keystream fault location differential engine stream cipher LIZARD

Interactive Effect and Spatial Characteristics of Agricultural Development Level and Transport Superiority Degree in Main Grain-producing Areas of the Central Jilin Province,China

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Chinese Geographical Science 2022年第4期32卷 643-664页

作者： tian tian MA Yanji Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

To investigate the spatial synergy between agricultural development level and transport superiority degree in grain-producing areas of the central Jilin Province and the driving mechanism between them,22 counties in the central Jilin Province were used as the research units to calculate agricultural development level and transport superiority degree using the entropy weighting method,weighted travel time and raster cost *** spatial econometric model was used to analyze the mechanism of the mutual influence between the *** main conclusions are as follows.1)Agricultural development level around Changchun,the provincial capital city,and in the areas of Changchun-Jilin and Changchun-Gongzhuling is high,whereas the development level of the counties in the southwest is low.2)Transport superiority degree of each county has improved,the overall connectivity of the road networks has been optimized,and the level of transportation accessibility has shown the development trend of‘centralization’,exhibiting the characteristics of proximity diffusion.3)Locally,there is spatial heterogeneity in the mutual driving effects of the two,with six main patterns.4)The theoretical conditions of von Thunen’s agricultural location have changed under the conditions of market economy due to the improvement of the transport networks,the new model of agricultural development,and the changes of the market system.

关键词： main grain-producing areas agricultural development level transport superiority degree coordination spatial and temporal differentiation

A Note on Determine the Greatest Common Subfamily of Two NFSRs by Grbner Basis

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Journal of Systems Science & Complexity 2015年第5期28卷 1231-1242页

作者： WANG Zhongxiao QI Wenfeng tian tian Luoyang University of Foreign Language State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Information Science and Technology Institute

For nonlinear feedback shift registers(NFSRs), their greatest common subfamily may be not unique. Given two NFSRs, the authors only consider the case that their greatest common subfamily exists and is unique. If the greatest common subfamily is exactly the set of all sequences which can be generated by both of them, the authors can determine it by Grbner basis theory. Otherwise, the authors can determine it under some conditions and partly solve the problem.

关键词： Greatest common subfamily Grbner basis nonlinear feedback shift register stream cipher

A New Distinguishing Attack on Grain-V1 with 111 Initialization Rounds

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Journal of Systems Science & Complexity 2019年第3期32卷 970-984页

作者： MA Zhen tian tian QI Wenfeng National Digital Switching System Engineering & Technological Research Center

The Grain-v1 stream cipher has been selected in the eSTREAM hardware finalists. In this paper, the authors derive a new distinguishing attack on Grain-v1 with 111 initialization rounds in a single-key setting. To achieve this goal, the authors present two delicate strategies targeting an obvious distinguishing probability of the output difference of reduced Grain-v1. The authors show that conditional differential cryptanalysis of reduced Grain-v1 with 111 initialization rounds could mount a distinguishing attack with success probability about 0.8281 for all secret keys. It is also shown that when the attacking round further increases to 112 and 113, the distributions of the output differences are nearly random. Thus far, to the best of the authors' knowledge, the attack on Grain-v1 with 111 initialization rounds is the best single-key cryptanalytic result for reduced versions of Grain-vl in terms of the number of attacking rounds.

关键词： Cryptanalysis differential cryptanalysis distinguishing attack Grain-v1 stream cipher

On Characteristic Functions of De Bruijn Sequences

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Chinese Journal of Electronics 2016年第2期25卷 304-311页

作者： TANG Zhenwei QI Wenfeng tian tian Department of Applied Mathematics Zhengzhou Information Science and Technology Institute

In 1982, H. Fredricksen presented the upper and lower bounds of the number of ones in the truth table of characteristic functions of de Bruijn sequences. In this paper, the distribution of ones in the truth table of characteristic functions of de Bruijn sequences is further studied. We provide the upper and lower bounds of the number of ones in the partial truth table of characteristic functions of de Bruijn sequences. Furthermore, the two bounds are tight.

关键词： Nonlinear feedback shift registers De Bruijn sequences Weight of the truth table

Evolutionary Generation Approach of Test Data for Multiple Paths Coverage of Message-passing Parallel Programs

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Chinese Journal of Electronics 2014年第2期23卷 291-296页

作者： tian tian GONG Dunwei School of Information and Electrical Engineering China University of Mining and Technology

Test data generation, the premise of software testing, has attracted scholars in the software engineering community in recent years. Influenced by task partitioning, process scheduling, and network delays, parallel programs are executed in a non-deterministic way, which makes test data generation of parallel programs different from that of serial programs in essence. This paper investigated the problem of generating test data for multiple paths coverage of message-passing parallel programs. A mathematical model of the above problem was built based on each given path and its equivalent ones. It was solved by using a genetic algorithm to generate all desired data in one run. The proposed method was applied to five benchmark programs, and compared with the existing *** experimental results show that the proposed method greatly shortens the number of iterations and time consumption without reducing the coverage rate.

关键词： Software testing Parallel program Multiple paths Test data Genetic algorithm