Remarks on breaking the Vigenère autokey cipher

Abstract

It has been mentioned by Shannon that a Vigenère autokey ciphertext can be transformed into a Vigenère ciphertext, provided the length of the priming key is known. We revisit this transformation and argue that combining it with the Friedman test, in fact, allows revealing of the length of the priming key. Thus, Shannon’s transformation together with the Friedman test allow transforming a Vigenère autokey ciphertext into a Vigenère ciphertext without any prior information. This allows an adversary to solve a Vigenère autokey ciphertext as if it was a Vigenère ciphertext. In addition, we show that the same method can be used to solve a modification of the Vigenère autokey cipher used in the Russian Civil War in 1917–1922.     

Neural networks for modelling and fault detection of the inter-stand strip tension of a cold tandem mill

This paper deals with the multilayered approach of the high-order neural network applied in a robust fault detection scheme. To introduce dynamic properties in these networks, a dynamic high-order neural unit is presented. It is shown that these networks can approximate any function with less parameters than in the case of multi-layer perceptron neural network. Such networks have good modelling properties, which make them useful for designing residuals in fault detection of dynamic processes. A method of computing a variable threshold derived from the confidence interval prediction is applied in order to obtain robustness in the fault detection process. Application of these networks for system identification and robust fault detection of the inter-stand strip tension of a continuous five stands cold mill is presented in the final part.     

Optimierung des Betoniervorgangs und der Mindestbewehrung einer massiven Bodenplatte

Optimisation of Concrete Casting Procedure and the Minimum Reinforcement of a Massive Foundation Slab The early age behaviour of a massive, joint less and watertight foundation slab was investigated in detail. The investigation was performed using a numerical model considering endogenous and exogenous effects, and it was complemented by in‐situ measurements. The results showed a significant influence of in‐situ climatic conditions during concreting on the necessary reinforcement content. The deformation measurements indicate a low degree of fixity of the slab. Also, the minimum reinforcement favours a better distribution of stresses as built‐in by internal deformation gradients in the slab.     

Characterization of some plant extracts by GC-MS

Different types of herbs often used in pharmaceutical, cosmetic and food industry were extracted and then analyzed by gas chromatography and gas chromatography-mass spectrometry. The method validation parameters showed good linearity, precision and recovery for a standard mixture. Herbs from different zones of Romania were studied: melissa (Melissa officinalis), nettle (Urtica dioica, Lamium album), camomile (Matricaria chamomilla). The study was applied for fingerprint chromatograms to characterize the flavors extracted from herb plants of different sources. The identity and quantity of the measured active compounds was correlated with the expected therapeutic effects. The active principles content was determined for the same herb, and different amounts of the active principles were determined for plants of different origin.     

Fragment Formal Concept Analysis Accurately Classifies Compounds with Closely Related Biological Activities

Fragment formal concept analysis (FragFCA) for compound classification: Signature fragment combinations for compound classes with closely related biological activity were identified using FragFCA. These combinations are used to accurately classify active test compounds on the basis of fragment mapping. FragFCA can extract class‐specific fragment combinations from compounds active against different target families that have signature character and practical utility in compound classification and database searching.

     

Mikroskopisch-f?rberischer Nachweis von Weizen-, Roggen-und Kartoffelst?rke nebeneinander

Zusammenfassung 1. Das Wesentliche der neuen Mehlfärbung besteht in der Metachromasie des Safranins durch die einzelnen Stärkearten.2. Carbollösung ist ein unentbehrliches Hilfsmittel zur Deutlichmachung der Strukturunterschiede.3. Im Gegensatz zu den bisher gebotenen Möglichkeiten, Kartoffelstärke einerseits von Weizen- und Roggenstärke andererseits färberisch zu unterscheiden, versetzt uns die neue Mehlfärhung in die Lage, Kartoffel-, Weizen- und Roggenstärke nebeneinander zu bestimmen.4. Eine hinreichend genaue quantitative Bestimmung der drei genannten Stärkearten nebeneinander ist damit gegeben.5. Die Beyerinck'sche Hypothese über einen chemischen Unterschied zwischen dem sogenannten Kartoffelmantel und der übrigen Substanz des Kartoffelstärkekorns erfährt eine wesentliche Unterstützung.     

Structural and rheological investigation of low density polyethylenes

Some low density polyethylenes (LDPE) with different melt flow index (MFI) or produced by different producers have been examined in detail by solvent gradient fractionation, ¹³C NMR analysis, FTIR spectroscopy and melt rheological measurements. It was found that the distribution curves of the samples resemble Wesslau's logarithmic-normal model. From branching analyses it can be concluded that the branching content in the analyzed LDPEs is independent from the molecular weight. Relations between viscosity curve parameters and molecular structure have been investigated. It has been found that the dependence of the first normal stress difference on the shear stress is influenced by polydispersity as well as by the character of samples branching.