Introduction to Public Key Infrastructures

The introduction of public key cryptography (PKC) was a critical advance in IT security. In contrast to symmetric key cryptography, it enables confidential communication between entities in open networks, in particular the Internet, without prior contact. Beyond this PKC also enables protection techniques that have no analogue in traditional cryptography, most importantly digital signatures which for example support Internet security by authenticating software downloads and updates. Although PKC does not require the confidential exchange of secret keys, proper management of the private and public keys used in PKC is still of vital importance: the private keys must remain private, and the public keys must be verifiably authentic. So understanding so-called public key infrastructures (PKIs) that manage key pairs is at least as important as studying the ingenious mathematical ideas underlying PKC.

In this book the authors explain the most important concepts underlying PKIs and discuss relevant standards, implementations, and applications. The book is structured into chapters on the motivation for PKI, certificates, trust models, private keys, revocation, validity models, certification service providers, certificate policies, certification paths, and practical aspects of PKI.

This is a suitable textbook for advanced undergraduate and graduate courses in computer science, mathematics, engineering, and related disciplines, complementing introductory courses on cryptography. The authors assume only basic computer science prerequisites, and they include exercises in all chapters and solutions in an appendix. They also include detailed pointers to relevant standards and implementation guidelines, so the book is also appropriate for self-study and reference by industrial and academic researchers and practitioners.

Johannes A. Buchmann has been a Professor of Computer Science and Mathematics at the Technische Universitat Darmstadt since 1996. He received his PhD in Mathematics from the Universitat zu Koln in 1982, and his Habilitation in Mathematics from the Universitat Dusseldorf in 1988. He was a Professor of Computer Science at the Universitat des Saarlandes from 1988 to 1996. Among many awards he received a Feodor Lynen Fellowship from the Alexander von Humboldt Foundation, the Leibniz Award of the German Science Foundation (Deutsche Forschungsgemeinschaft), the Karl Heinz Beckurts Prize, and the IT Security Prize of the Horst Gortz Foundation. He has advised companies such as Siemens, Hitachi, Sony, NTT, Schenck, Microsoft, and Lufthansa, and the BSI, the German Federal Office for Information Security. He is a member of the German Academy of Sciences and Literature, Mainz; the German National Academy of Sciences, Leopoldina; Acatech, the German Academy of Science and Engineering, Munich; and the Berlin-Brandenburg Academy of Sciences and Humanities, Berlin. He has chaired related cryptology conferences and was a board member of the Journal of Cryptology from 1990 to 2009. Among his key book publications are the textbook "Introduction to Cryptography" (Springer, 2004, 2nd ed.), and he has supervised 57 Ph.D. students and lectured on information security, cryptology, and related mathematical methods.

Evangelis Karatsiolis obtained his PhD in 2007 from the Technische Universitat Darmstadt for his thesis "Flexible Certificate Management in Public Key Infrastructures"; he works for FlexSecure GmbH in Darmstadt.

Alexander Wiesmaier obtained his PhD in 2008 from the Technische Universitat Darmstadt for his thesis "Secure Private Key Management in Adaptable Public Key Infrastructures". He is a lead security architect at AGT Group (R&D) GmbH in Darmstadt, working on critical infrastructure protection, safety, and security.