排序方式: 共有45条查询结果,搜索用时 796 毫秒
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A new, vectorial approach to fast correlation attacks on binary memoryless combiners is proposed. Instead of individual input sequences or their linear combinations, the new attack is targeting subsets of input sequences as a whole thus exploiting the full correlation between the chosen subset and the output sequence. In particular, the set of all the input sequences can be chosen as the target. The attack is based on a novel iterative probabilistic algorithm which is also applicable to general memoryless combiners over finite fields or finite rings. To illustrate the effectiveness of the introduced approach, experimental results obtained for random balanced combining functions are presentedMost of this work was done while he was with Rome CryptoDesign Center, Gemplus, Italy 相似文献
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The motion of a holonomic scleronomic non-conservative mechanicalsystem with minimal dissipation is considered. As applicationsof the theory several problems are studied in detail. 相似文献
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Marvin RG Wolford JL Kidd MJ Murphy S Ward J Que EL Mayer ML Penner-Hahn JE Haldar K O'Halloran TV 《Chemistry & biology》2012,19(6):731-741
Dynamic fluxes in the concentration of ions and small molecules are fundamental features of cell signaling, differentiation, and development. Similar roles for fluxes in transition metal concentrations are less well established. Here, we show that massive zinc fluxes are essential in the infection cycle of an intracellular eukaryotic parasite. Using single-cell quantitative imaging, we show that growth of the blood-stage Plasmodium falciparum parasite requires acquisition of 30 million zinc atoms per erythrocyte before host cell rupture, corresponding to a 400% increase in total zinc concentration. Zinc accumulates in a freely available form in parasitophorous compartments outside the food vacuole, including mitochondria. Restriction of zinc availability via small molecule treatment causes a drop in mitochondrial membrane potential and severely inhibits parasite growth. Thus, extraordinary zinc acquisition and trafficking are essential for parasite development. 相似文献
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A Mukherjee M Dasgupta DJ Hinde CR Morton AC Berriman RD Butt JO Newton H Timmers 《Pramana》2001,57(1):195-198
Fusion cross-sections for the 7Li + 12C reaction have been measured at energies above the Coulomb barrier by the direct detection of evaporation residues. The heavy
evaporation residues with energies below 3 MeV could not be separated out from the α-particles in the spectrum and hence their
contribution was estimated using statistical model calculations. The present work indicates that suppression of fusion cross-sections
due to the breakup of 7Li may not be significant for 7Li + 12C reaction at energies around the barrier. 相似文献
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The alternating step generator is a well-known keystream generator consisting of two stop/go clocked LFSRs, LFSR1 and LFSR2, whose clocks are controlled by another LFSR, LFSR3, which is clocked regularly. A probabilistic analysis of this generator is conducted which shows that the posterior probabilites of individual bits of the first derivatives of the regularly clocked LFSR1 and LFSR2 sequences, when conditioned on a given segment of the first derivative of the keystream sequence, can be computed efficiently in a number of probabilistic models of interest. The expected values of these probabilities, for a random keystream sequence, are derived by an approximate theoretical analysis and are also verified by systematic computer experiments. It is pointed out that these posterior probabilities can be enhanced in a resynchronization scenario and thus used for a low-complexity fast correlation attack on the two LFSRs. More generally, it is argued that even without resynchronization these probabilities may be significantly different from one half for fast correlation attacks based on iterative decoding algorithms to be successful, although with incresead complexity. A related method for computing the posterior probabilities of individual bits of the LFSR3 sequence, when conditioned on both the keystream sequence and the LFSR1 and LFSR2 sequences, is also developed. As these posterior probabilities are much more different from one half, they can be used for a low-complexity fast correlation attack on LFSR3, provided that the initial states of LFSR1 and LFSR2 are previously reconstructed. 相似文献
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