Complex systems are of vast importance in the practical world as well as presenting many theoretical challenges. The measurement of system complexity is still imprecise. For many systems, their modular construction brings challenges in understanding how modules form and the emergent behavior...

This text was written as part of the project Modelling of Complex Systems for Public Policy. It reviews the classical authors who jointly contributed to establish the elements of what could constitute a “science of complexity”. Based on the original writings of these authors, the text...

The security of Fridrich's algorithm against brute-force attack, statistical attack, known-plaintext attack and select-plaintext attack is analyzed by investigating the properties of the involved chaotic maps and diffusion functions. Based on the given analyses, some means are proposed to...

Current trends indicate that IT security measures will need to greatly expand to counter the ever increasingly sophisticated, well-funded and/or economically motivated threat space. Traditional risk management approaches provide an effective method for guiding courses of action for assessment,...

The problem of sharing manufacturing, inventory, or capacity to improve performance is applicable in many decentralized operational contexts. However, the solution of such problems commonly requires an intermediary or a broker to manage information security concerns of individual participants....

In der Arbeit soll die Wirtschaftlichkeit von Zertifizierungsstellen in Deutschland untersucht werden. Es erfolgt eine kurze Einführung in die technischen Grundlagen von Zertifizierungsstellen und Zertifikaten, die neben kryptographischen Verfahren der Verschlüsselung und Signatur die im...

We explore the consequences of the assumptions used in modern cryptographywhen applied to repeated games with public communication. Technically speaking, we model agents by polynomial Turing machinesand assume the existence of a trapdoor function. Under these conditions, we prove a Folk Theorem...