This book constitutes the refereed proceedings of the 12th International Conference on Applied Cryptography and Network Security, ACNS 2014, held in Lausanne, Switzerland, in June 2014. The 33 revised full papers included in this volume were carefully reviewed and selected from 147 submissions. They are organized in topical sections on key exchange; primitive construction; attacks (public-key cryptography); hashing; cryptanalysis and attacks (symmetric cryptography); network security; signatures; system security; and secure computation.

The First International Workshop on Traffic Monitoring and Analysis (TMA 2009) was an initiative from the COST Action IC0703 "Data Traffic Monitoring and Analysis: Theory, Techniques, Tools and Applications for the Future Networks" (www.cost-tma.eu). The COST program is an intergovernmental framework for European Cooperation in Science and Technology, allowing the coordination of nationally funded research on a European level. Each COST Action contributes to reducing the fragmentation in research and opening the European Research Area to cooperation worldwide. Traffic monitoring and analysis (TMA) is now an important research topic within the field of networking. It involves many research groups worldwide that are coll- tively advancing our understanding of the Internet. The importance of TMA research is motivated by the fact that modern packet n- works are highly complex and ever-evolving objects. Understanding, developing and managing such environments is difficult and expensive in practice. Traffic monitoring is a key methodology for understanding telecommunication technology and improving its operation, and the recent advances in this field suggest that evolved TMA-based techniques can play a key role in the operation of real networks. Moreover, TMA offers a basis for prevention and response in network security, as typically the det- tion of attacks and intrusions requires the analysis of detailed traffic records. On the more theoretical side, TMA is an attractive research topic for many reasons.

The 1999 International Workshop on Interactive Distributed Multimedia Sys tems and Telecommunication Services (IDMS) in Toulouse is the sixth in a se ries that started in 1992. The previous workshops were held in Stuttgart in 1992, Hamburg in 1994, Berlin in 1996, Darmstadt in 1997, and Oslo in 1998. The area of interest of IDMS ranges from basic system technologies, such as networking and operating system support, to all kinds of teleservices and distributed multimedia applications. Technical solutions for telecommunications and distributed multimedia systems are merging and quality-of-service (QoS) will play a key role in both areas. However, the range from basic system tech nologies to distributed mutlimedia applications and teleservices is still very broad and we have to understand the implications of multimedia applications and their requirements for middleware and networks. We are challenged to develop new and more fitting solutions for all distributed multimedia systems and telecom munication services to meet the requirements of the future information society."