Sachar Paulus | Mannheim University of Applied Sciences (original) (raw)

Papers by Sachar Paulus

Angewandte Wirtschaftsinformatik, 2018

Selected Areas in Cryptography, Aug 14, 2000

Cryptosystems based on the discrete logarithm problem in the infrastructure of a real quadratic n... more Cryptosystems based on the discrete logarithm problem in the infrastructure of a real quadratic number field [7],[19],[2] are very interesting from a theoretical point of view, because this problem is known to be at least as hard as, and when considering todays algorithms - as in [11] - much harder than, factoring integers. However it seems that the cryptosystems sketched in [2] have not been implemented yet and consequently it is hard to evaluate the practical relevance of these systems. Furthermore as [2] lacks any proofs regarding the involved approximation precisions, it was not clear whether the second communication round, as required in [7],[19], really could be avoided without substantial slowdown. In this work we will prove a bound for the necessary approximation precision of an exponentiation using quadratic numbers in power product representation and show that the precision given in [2] can be lowered considerably. As the highly space consuming power products can not be applied in environments with limited RAM, we will propose a simple (CRIAD1-) arithmetic which entirely avoids these power products. Beside the obvious savings in terms of space this method is also about 30% faster. Furthermore one may apply more sophisticated exponentiation techniques, which finally result in a ten-fold speedup compared to [2]. CRIAD is an abbreviation for Close Reduced Ideal and Approximated relative Distance

Mathematics of Computation, Oct 26, 2000

Wie Corona die Hochschullehre verändert, 2021

Communications in Computer and Information Science, 2013

ABSTRACT Cloud- and service-oriented computing paradigms are intrinopaque to their users, as they... more ABSTRACT Cloud- and service-oriented computing paradigms are intrinopaque to their users, as they cannot inspect providers’ implementations, and important concerns about aspects like security, compliance, dependability can arise. Therefore, users have to make trust decisions with respect to software providers, with the hope that there will not be any detrimental consequences. To contrast this situation, the paper proposes a framework to define, assess, monitor and make explicit the elements of a service that render it trustworthy. This paper relies on a number of recent scientific contributions, and aims at supporting informed decisions on obscure service implementations by machine-understandable statements about their objective (trustworthiness) characteristics. Such statements would innovate upon many aspects of service operations, from discovery to composition, deployment and monitoring. To demonstrate this, the paper presents a concept for a Trustworthy Service Marketplace.

International Conference on Information Security and Cryptology, Dec 1, 1998

We present a generalization of the Diffie-Hellman problem. It is based on the problem ofdetermini... more We present a generalization of the Diffie-Hellman problem. It is based on the problem ofdetermining coset representatives of group &amp;amp;quot;extensions&amp;amp;quot;. This generic one-way function allowsthe development of ElGamal-like encryption protocols where the decryption process is muchfaster than in existing protocols, while providing the same security. As examples, we presentand analyze protocols using ZZ=nZZ, using elliptic curves and using class groups

Digitalisierung in Unternehmen, 2018

The need for process improvement is an important target that does affect as well the government p... more The need for process improvement is an important target that does affect as well the government processes. Specifically in the public sector there are specific challenges to face .New technology approaches within government processes such as cloud services are necessary to address these challenges. Following the current discussion of "cloudification"of business processes all processes are considered similar in regards to their usability within the cloud. The truth is, that neither all processes have the same usability for cloud services not do they have the same importance for a specific company. The most comprehensive process within a company is the corporate value chain. In this article one key proposition is to use the corporate value chain as the fundamental structuring backbone for all business process analysis and improvement activities. It is a pre-requisite to identify the core elements of the value chain that are essential for the individual company's business...

Industrie 4.0 und Digitalisierung bedeuten insbesondere, dass Maschinen, Gerate und produzierte G... more Industrie 4.0 und Digitalisierung bedeuten insbesondere, dass Maschinen, Gerate und produzierte Guter mit „Intelligenz“ versehen und miteinander vernetzt werden. Die „Intelligenz“ wird durch ein Einsatz von Software realisiert; Software ist jedoch prinzipbedingt sehr leicht angreifbar – und die Vernetzung eroffnet viele neue Angriffswege. Die IT-Branche hat den Prozess der Vernetzung vor ca. 20 Jahren begonnen – und hat es bis heute trotz viel Forschung und grosen Investitionen nicht vollstandig geschafft, sichere Software herstellen zu konnen. Sichere Software zu entwickeln scheint daher nicht so einfach zu sein. Wie konnen Maschinen-Software-Hersteller das Wissensdefizit moglichst schnell aufholen?

Available from TIB Hannover: RR 1608(1996,8) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - T... more Available from TIB Hannover: RR 1608(1996,8) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Datenschutz Und Datensicherheit Dud, 2006

Datenschutz Und Datensicherheit Dud, 2011