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A Random PRESENT Encryption Algorithm Based on Dynamic S-box
Zhiying Tang,Jie Cui,Hong Zhong,Mingyong Yu 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.3
S-box mainly plays the role of confusion in the encryption process as an important component. For the new encryption algorithm PRESENT proposed in 2007, S-box impacts on the security of the encryption algorithm directly. This paper briefly describes the process of PRESENT algorithm and proposes an improved S-box to solve the problem that the original PRESENT S-box has anti-fixed point. Then a random PRESENT encryption algorithm based on dynamic S-box is proposed. The dynamic multiple S-boxes technology is used to implement random PRESENT algorithm, to enhance the security of the cryptographic algorithm. Finally, the security analysis is done, and it suggests that dynamic S-box has a superior ability to resist differential attack and linear attack. By comparison to the diffusion rate of original PRESENT S-box, our dynamic S-box has better avalanche effect.
Qiantang Fu,Chaoqiong Li,Mingyong Tang,Yan-Bin Tao,Bang-Zhen Pan,Lu Zhang,Longjian Niu,Huiying He,Xiulan Wang,Zeng-Fu Xu 한국식물생명공학회 2015 Plant biotechnology reports Vol.9 No.6
Jatropha curcas is considered a potential biodiesel feedstock crop. Currently, the value of J. curcas is limited because its seed yield is generally low. Transgenic modification is a promising approach to improve the seed yield of J. curcas. Although Agrobacterium-mediated genetic transformation of J. curcas has been pursued for several years, the transformation efficiency remains unsatisfying. Therefore, a highly efficient and simple Agrobacterium-mediated genetic transformation method for J. curcas should be developed. We examined and optimized several key factors that affect genetic transformation of J. curcas in this study. The results showed that the EHA105 strain was superior to the other three Agrobacterium tumefaciens strains for infecting J. curcas cotyledons, and the supplementation of 100 mM acetosyringone slightly increased the transient transformation frequency. Use of the appropriate inoculation method, optimal kanamycin concentration and appropriate duration of delayed selection also improved the efficiency of stable genetic transformation of J. curcas. The percentage of b-glucuronidase positive J. curcas shoots reached as high as 56.0 %, and 1.70 transformants per explant were obtained with this protocol. Furthermore, we optimized the root-inducing medium to achieve a rooting rate of 84.9 %. Stable integration of the T-DNA into the genomes of putative transgenic lines was confirmed by PCR and Southern blot analysis. Using this improved protocol, a large number of transgenic J. curcas plantlets can be routinely obtained within approximately 4 months. The detailed information provided here for each step of J. curcas transformation should enable successful implementation of this transgenic technology in other laboratories.