Dining Cryptographers Networks: Praktikable Werkzeuge zur Wahrung der Anonymität?

Die vorliegende Arbeit beschäftigt sich mit einer speziellen Technik zur Wahrung von Anonymität in Rechnernetzen den sogenannten 'Dining Cryptographers Networks' (DC-Netze). Diese Netze haben im Vergleich zu anderen anonymisierenden Mechanismen die besondere Eigenschaft, daß ihre Sicherheit kompexitätstheoretisch mit nur wenigen Annahmen bewiesen werden kann. Neben der Betrachtung der Algorithmen und Protokolle wird gleichzeitig eine freie prototypische Implementierung mit Namen 'GnuDCN' bereitgestellt, um die praktische Relevanz solcher DC-Netze zu klären. Das System ist trotz seines enormen Kommunikationsaufwands in sensiblen Umgebungen mit kleinem Teilnehmerkreis durchaus einsetzbar.The available work concerns itself with a special technology for the keeping of anonymity in computer networks the so-called 'Dining Cryptographers Networks' (DC nets). These nets have the special characteristic compared with other anonymizating mechanisms that their security can be proven with only few assumptions. Apart from the view of the algorithms and protocols a free prototypic implementation with name 'GnuDCN' is made available at the same time, in order to clarify the practical relevance of such DC nets. The system is quite applicable despite its enormous communication expenditure in sensitive environments with small participant circle

Dining Cryptographers Networks: Praktikable Werkzeuge zur Wahrung der Anonymität?

Die vorliegende Arbeit beschäftigt sich mit einer speziellen Technik zur Wahrung von Anonymität in Rechnernetzen den sogenannten 'Dining Cryptographers Networks' (DC-Netze). Diese Netze haben im Vergleich zu anderen anonymisierenden Mechanismen die besondere Eigenschaft, daß ihre Sicherheit kompexitätstheoretisch mit nur wenigen Annahmen bewiesen werden kann. Neben der Betrachtung der Algorithmen und Protokolle wird gleichzeitig eine freie prototypische Implementierung mit Namen 'GnuDCN' bereitgestellt, um die praktische Relevanz solcher DC-Netze zu klären. Das System ist trotz seines enormen Kommunikationsaufwands in sensiblen Umgebungen mit kleinem Teilnehmerkreis durchaus einsetzbar.The available work concerns itself with a special technology for the keeping of anonymity in computer networks the so-called 'Dining Cryptographers Networks' (DC nets). These nets have the special characteristic compared with other anonymizating mechanisms that their security can be proven with only few assumptions. Apart from the view of the algorithms and protocols a free prototypic implementation with name 'GnuDCN' is made available at the same time, in order to clarify the practical relevance of such DC nets. The system is quite applicable despite its enormous communication expenditure in sensitive environments with small participant circle

Efficient electronic gambling: An extended implementation of the toolbox for mental card games

Abstract: There are many wonderful protocols in cryptography which are still waiting for their realization. Here we consider efficient solutions for secure electronic card games. Our contribution seems to be the first known practical implementation that requires no trusted third-party and simultaneously keeps the players ’ strategies confidential. The provided open source library LibTMCG can be used for creating secure peer-to-peer games and furthermore for some unusual applications, e.g., secure multiparty computation or simple electronic voting schemes

Dining Cryptographers Networks: Praktikable Werkzeuge zur Wahrung der Anonymität?

Die vorliegende Arbeit beschäftigt sich mit einer speziellen Technik zur Wahrung von Anonymität in Rechnernetzen den sogenannten 'Dining Cryptographers Networks' (DC-Netze). Diese Netze haben im Vergleich zu anderen anonymisierenden Mechanismen die besondere Eigenschaft, daß ihre Sicherheit kompexitätstheoretisch mit nur wenigen Annahmen bewiesen werden kann. Neben der Betrachtung der Algorithmen und Protokolle wird gleichzeitig eine freie prototypische Implementierung mit Namen 'GnuDCN' bereitgestellt, um die praktische Relevanz solcher DC-Netze zu klären. Das System ist trotz seines enormen Kommunikationsaufwands in sensiblen Umgebungen mit kleinem Teilnehmerkreis durchaus einsetzbar.The available work concerns itself with a special technology for the keeping of anonymity in computer networks the so-called 'Dining Cryptographers Networks' (DC nets). These nets have the special characteristic compared with other anonymizating mechanisms that their security can be proven with only few assumptions. Apart from the view of the algorithms and protocols a free prototypic implementation with name 'GnuDCN' is made available at the same time, in order to clarify the practical relevance of such DC nets. The system is quite applicable despite its enormous communication expenditure in sensitive environments with small participant circle

On Oleshchuk\u27s Public Key Cryptosystem

This paper revisits a public key cryptosystem which is based on finite Church-Rosser string-rewriting systems. We consider some ideas for cryptanalysis and discuss issues concerning practical usage. It turns out that without changing crucial details of key generation this cryptosystem does not offer acceptable cryptographic security. We also provide the source code of our rudimentary implementation, if someone would like to use it for further cryptanalysis

Completion Attacks and Weak Keys of

Abstract. This paper revisits a public key cryptosystem which is based on finite string-rewriting systems. We consider a new approach for cryptanalysis of such proposals—the so-called completion attack. If a particular kind of weak key is generated, then a passive adversary is able to retrieve secret messages with a significant probability. Our idea can be applied to other rewriting based cryptosystems as well. Finally we discuss issues concerning the practical usage and present some experimental results. The described vulnerabilities lead to the conclusion that at least the key generation of Oleshchuk’s cryptosystem has to be revised